Search

Background: Analysis of binding patterns of biomolecules underpin new paradigms for trait engineering. One way of designing early flowering crops is to manipulate genes controlling flowering time. SOC1, a central integrator of flowering, is downregulated by SVP. In amphidiploid Brassica juncea, flowering is plausibly mediated by combinatorial interactions involving natural variants of SOC1 promoter and SVP protein homologs. Although fluctuating temperatures influence energetics of molecular interactions and phenotypes, mechanistic insights on these remain unknown. Herein, we report diversity in 50 homologs of SVP proteins from 25 Brassicaceae species. Materials and Methods and Results: Sequence and phylogenetic analysis of 9 natural variants of B. juncea SVP revealed differences in MIKC domains and sub-genome of origin. Generation and refinement of 15 SVP protein models (natural and hypothetical) using I-TASSER and ALPHAFOLD, and 3 SOC1 promoter fragments using 3D-DART, revealed structural diversity. Notwithstanding, binding affinity of 48 docked complexes analysed using HADDOCK and PreDBA were similar. Analysis of 27 docked complexes for distribution of shared or unique binding patterns and type of molecular contacts (π-π stacking, hydrophobic interactions, Van-der-Waals forces, H-bonds) using PyMOL, CCP4i, DNAproDB, PremPDI and DIMPLOT revealed extensive variation implicating compensatory mutations in preserving binding affinity. Yeast one-hybrid assays validated binding potential predicted in docked complexes. Conserved amino-acid and nucleotide residues involved in non-covalent interactions were identified. Computational alanine substitution established cruciality of amino-acid hotspots conferring stability to docked complexes. Conclusions: Our study is important as identification of crucial amino-acid hotspots is essential for rational protein design. Targeted mutagenesis resulting in modified binding spectrum of regulatory proteins suggests a way forward for trait engineering. [ABSTRACT FROM AUTHOR]

Plants have evolved sophisticated signaling networks to adjust flowering time, ensuring successful reproduction. Two crucial flowering regulators, FLOWERING LOCUS T (FT) and CONSTANS (CO), play pivotal roles in regulating flowering across various species. Previous studies have indicated that suppressing Gossypium hirsutum CONSTANS-LIKE 2 (GhCOL2), a homolog of Arabidopsis CO, leads to delayed flowering in cultivated cotton. However, the underlying regulatory mechanisms remain unknown. In this study, a yeast one-hybrid and dual-LUC expression assays were used to elucidate the molecular mechanism through which GhCOL2 regulates the transcription of GhHD3A. RT-qPCR was used to examine the expression of GhCOL2 and GhHD3A. Our findings reveal that GhCOL2 directly binds to CCACA cis-elements and atypical CORE (TGTGTATG) cis-elements in the promoter regions of HEADING DATE 3 A (HD3A), thereby activating GhHD3A transcription. Notably, GhCOL2 and GhHD3A exhibited high expression levels in the adult stage and low levels in the juvenile stage. Interestingly, the expression of GhCOL2 and GhHD3A varied significant between the two cotton varieties (Tx2094 and Maxxa). In summary, our study enhances the understanding of the molecular mechanism by which cotton GhCOL2-GhHD3A regulates flowering at the molecular level. Furthermore, it contributes to a broader comprehension of the GhCOL2-GhHD3A model in G. hirsutum. [ABSTRACT FROM AUTHOR]

Ethylene is a pivotal regulator of coffee anthesis, and 1-methylcyclopropene (1-MCP), an ethylene action inhibitor, offers a potential to manage flowering in coffee plants. This study aimed to identify the effect of 1-MCP on gene expression of ethylene receptors, and compare the interaction in silico between 1-MCP and different ethylene receptors to understand what could be associated with coffee anthesis promotion by this molecule. The study involved phenotypic characterization, ethylene quantification, RNA expression profiling, phylogenetic analysis, homology modeling, and molecular docking. Results revealed that 1-MCP accelerated floral bud development to anthesis within 12 days, contrasting with water treated floral buds which exhibited progress just after a rainfall event. Moreover, 1-MCP application notably increased ethylene levels in both leaves and floral buds. Gene expression analysis indicated that 1-MCP modulates ethylene related gene expression differently in leaves and floral buds. Decreasing the expression of signaling genes in floral buds (CaERS1-like, ETR2-like, ETR4-like and EIN4-like), increasing it in leaves (ETR1-like, ETR2-like, ETR4-like and CaCTR1-like); and increasing the expression of CaACO3-like (biosynthesis related gene) in floral buds. Molecular docking studies suggested that ethylene may exhibit a higher affinity for receptors with lower interaction energy with 1-MCP. In conclusion, 1-MCP could be a promising tool to promote anthesis in coffee trees by modulating ethylene related processes, as the interaction between 1-MCP and ethylene receptors may influence ethylene sensitivity through different modulation of gene expression in leaves and floral buds. [ABSTRACT FROM AUTHOR]

Flowering marks the critical transition from vegetative to reproductive growth in plants. In this work, three vascular plant one-zinc finger (VOZ) genes, namely, MiVOZ1A, MiVOZ1B and MiVOZ2, were identified from mango (Mangifera indica). The expression levels of the three MiVOZs increased after salt and drought treatment, increased during the vegetative period, and then decreased during the floral induction period. MiVOZ1A and MiVOZ1B were expressed mainly in adult stems, leaves and juvenile stems, but MiVOZ2 was mainly had high expression in juvenile buds and adult stems. The expression levels of CONSTANS (AtCO) and FLOWERING LOCUS T (AtFT) increased and that of FLOWERING LOCUS C (AtFLC) decreased in the MiVOZ transgenic Arabidopsis lines, resulting in an earlier flowering phenotype under long-day (LD) and short-day (SD) conditions. However, the overexpression of MiVOZ reduced the tolerance of the transgenic Arabidopsis to salt and drought stress. In addition, the interaction between MiVOZ proteins and CONSTANS-Like 16 (MiCOL16) proteins in mango was confirmed in vivo via yeast two-hybrid (Y2H) assays and bimolecular fluorescence complementation (BiFC). This work demonstrated the functions of MiVOZ1A, MiVOZ1B and MiVOZ2 and provided a basis for further research on the regulation of mango flowering and molecular genetic breeding.Key message: Three MiVOZs were isolated from mango, and the overexpression of MiVOZs promoted earlier flowering and reduced tolerance to abiotic stresses in transgenic Arabidopsis. All three MiVOZs interact with MiCOL16A and MiCOL16B in vivo. [ABSTRACT FROM AUTHOR]

In plants, flowering is crucial to reproductive success. Receiving limited attention in apple research is the function of WRKY transcription factors in regulating flowering time. We characterized a WRKY transcription factor, MdWRKY71, from red-fleshed apple in this study, and ectopically expressed it in Arabidopsis thaliana, which revealed its role in flowering. The sequence of MdWRKY71 exhibited similarity to that of AtWRKY71, and its protein comprised a WRKY domain and a C2H2 zinc finger-like motif, placing it within subgroup IIc of the WRKY family. The similar changing trends demonstrated a significant positive correlation between the expression level of MdWRKY71 and the key flower transition genes in apical buds of apple in flower transition stage. Overexpression of MdWRKY71 promoted the upregulation of certain flower transition genes in apple calli. The ectopic expression of MdWRKY71 in A. thaliana was observed to induce early flowering. Additionally, MdWRKY71 could bind to the promoters of several floral pathway integrators directly and interact with them to enhance their expression levels. These results contribute to our understanding of the molecular mechanism through which MdWRKY71 regulates the flowering process in fruit trees, such as red-fleshed apple. Key message: We identified a WRKY transcription factor MdWRKY71 from red-fleshed apple and expressed it ectopically in Arabidopsis Thaliana, revealing its role in flowering. [ABSTRACT FROM AUTHOR]

Cotton, as a natural fiber crop, plays a pivotal role in advancing global textile industry. Comparative transcriptome analyses of single-cell 'fiber' from wild and domesticated plant revealed the evolutionary selection of cell wall-associated profilin gene family during cotton domestication. However, the evolutionary significance of elevated transcript abundance of profilins (GhPRFs) in floral and fiber tissues, and their practical application in the field for improving crop yield remain poorly understood. In this study, the domestication-driven 402 bp long GhPRF1 gene (Pro35Sde:GhPRF1-pA) was constitutively overexpressed in cotton (Gossypium hirsutum L. cv. Coker 310FR) through Agrobacterium-mediated genetic transformation of 1513 cotyledonary explants undergoing somatic embryogenesis. Out of the 32 putative GhPRF1 transgenic overexpression (Ox) lines produced, 26 lines were successfully confirmed with independent transgene integrations. Compared with those of the untransformed wild type (WT), the cumulative abundance of GhPRF1 transcripts in the leaf tissues of GhPRF1 overexpressing lines Pf-CaOx7, Pf-CaOx14, and Pf-CaOx19 substantially increased (> 12-fold). These transgenic lines exhibited increased numbers of secondary branches, flower buds per branch, and trichome density on the abaxial surface of leaves compared to the WT plants. Despite comparable fiber lengths between the overexpression lines and the WT, the enhanced fiber yields in the overexpression lines were attributed to increased flower number and boll production per branch. Remarkably, GhPRF1 overexpression also manifested transcriptional biases specific to profilin homologs in vegetative, floral, and fiber tissues. This is primarily attributed to increased actin polymerization and the formation of dense F-actin bundles, which are especially evident in the vascular regions of overexpression lines compared to those of the WT. This study revealed novel phenotypic and genetic foundations influencing floral and fiber architecture in cotton and offers promising avenues for manipulating agronomic traits. [ABSTRACT FROM AUTHOR]

Phytohormones promote growth in the vegetative phase, flowering and fruit development. A novel class of PGR comprises brassinosteroids (BRs) and polyamines (PAs). In fruit crops, fruit drop at the maturity stage is controlled by the external application of BRs and PAs. BRs such as brassinolide, 24-epibrassinolide and 28-homobrassinolide and PAs such as putrescine, spermidine and spermine play significant roles in plant growth and development. Brassinolide provides tolerance against biotic and abiotic stresses. 24-Epibrassinolide promotes blossoming, fruit retention, fruit set and fruit growth. 28-homobrassinolide promotes cell division and cell elongation. Putrescine enhances seed germination and adventitious root formation in seedlings. Moreover, spermidine provides tolerance against drought and salinity. Furthermore, spermine promotes flowering and fruiting and competes with ethylene precursors. It would be beneficial to apply plant growth regulators such as BRs and PAs to increase fruit yield and quality. This review discusses how phytohormone (BR and PA) application can improve the productivity, quality, physiological, biochemical and postharvest aspects of some tropical, subtropical and temperate fruits and focuses on research areas such as the mode of action and stage of application of BRs and PAs which enhance the yield and quality of these perishable fruit crops. Article highlights: The newly emerged plant growth hormones brassinosteroids and polyamines are vital PGRs for the cultivation of horticulture commodities. BRs and PAs are environmentally safe phytohormones that improve the yield and quality of fruits. These materials are effectively utilized in both fruit production and postharvest management. [ABSTRACT FROM AUTHOR]

Background: Hydroxynitrile lyases (HNLs) are a class of hydrolytic enzymes from a wide range of sources, which play crucial roles in the catalysis of the reversible conversion of carbonyl compounds derived from cyanide and free cyanide in cyanogenic plant species. HNLs were also discovered in non-cyanogenic plants, such as Arabidopsis thaliana, and their roles remain unclear even during plant growth and reproduction. Methods and results: The pattern of expression of the HNL in A. thaliana (AtHNL) in different tissues, as well as under abiotic stresses and hormone treatments, was examined by real-time quantitative reverse transcription PCR (qRT-PCR) and an AtHNL promoter-driven histochemical β-glucuronidase (GUS) assay. AtHNL is highly expressed in flowers and siliques, and the expression of AtHNL was dramatically affected by abiotic stresses and hormone treatments. The overexpression of AtHNL resulted in transgenic A. thaliana seedlings that were more tolerance to mannitol and salinity. Moreover, transgenic lines of A. thaliana that overexpressed this gene were less sensitive to abscisic acid (ABA). Altered expression of ABA/stress responsive genes was also observed in hnl mutant and AtHNL-overexpressing plants, suggesting AtHNL may play functional roles on regulating Arabidopsis resistance to ABA and abiotic stresses by affecting ABA/stress responsive gene expression. In addition, the overexpression of AtHNL resulted in earlier flowering, whereas the AtHNL mutant flowered later than the wild type (WT) plants. The expression of the floral stimulators CONSTANS (CO), SUPPRESSOR OF OVER EXPRESSION OF CO 1 (SOC1) and FLOWERING LOCUS T (FT) was upregulated in plants that overexpressed AtHNL when compared with the WT plants. In contrast, expression of the floral repressor FLOWERING LOCUS C (FLC) was upregulated in AtHNL mutants and downregulated in plants that overexpressed AtHNL compared to the WT plants. Conclusion: This study revealed that AtHNL can be induced under abiotic stresses and ABA treatment, and genetic analysis showed that AtHNL could also act as a positive regulator of abiotic stress and ABA tolerance, as well as flowering time. [ABSTRACT FROM AUTHOR]

During the last decade, the hairy rose beetle, Tropinota squalida ssp. pilosa (Brulle) (Coleoptera: Scarabaeidae), represents a recrudescent subspecies in fruit orchards of Central west Tunisia. This pest destroys flowers of pome- and stone-fruit species by feeding on their reproductive organs. The main goal of this study was to provide fundamental information on the flight activity of this pest in an attempt to find and establish effective control methods against it. The study was conducted in apple orchards of Foussena, located in Central west Tunisia, during springs of the years 2017, 2021 and 2022. Water traps used in field experiments were placed between rows of trees to capture the beetles. The results showed that the activity of beetles was closely associated with the temperature rise and apple blossom onset. Over three years, we observed seven weeks of flight activity in the field. This activity commenced in early March within orchards featuring early varieties where it lasted for 4 to 5 weeks. Following that, the activity came to a close after 3 weeks by late April in apple orchards with autumnal varieties. The most significant captures (50%) occurred in the second half of March. The flight pattern exhibited only one peak in the third week of March, suggesting that T. squalida pilosa is a monovoltine species. [ABSTRACT FROM AUTHOR]

Crocussativus is a valuable plant due to the presence of apocarotenoids in its stigma. Considerable work has been done in the past to understand the apocarotenoid biosynthetic pathway in saffron. However, the reports on understanding the regulation of flowering at the post-transcriptional level are meagre. The study aimed to discover the candidate miRNAs, target genes, transcription factors (TFs), and apocarotenoid biosynthetic pathway genes associated with the regulation and transition of flowering in C. sativus. In the present investigation, miRNA profiling was performed in flowering and non-flowering corms of saffron, along with expression analysis of apocarotenoid genes and transcription factors involved in the synthesis of secondary metabolites. Significant modulation in the expression of miR156, miR159, miR166, miR172, miR395, miR396, miR399, and miR408 gene families was observed. We obtained 36 known miRNAs (26 in flowering and 10 in non-flowering) and 64 novel miRNAs (40 in flowering and 24 in non-flowering) unique to specific tissues in our analysis. TFs, including CsMADS and CsMYb, showed significant modulation in expression in flowering tissue, followed by CsHB. Additionally, the miRNAs were predicted to be involved in carbohydrate metabolism, phytohormone signalling, regulation of flower development, and response to stress, cold, and defence. The comprehensive study has enhanced our understanding of the regulatory machinery comprising factors like phytohormones, abiotic stress, apocarotenoid genes, transcription factors, and miRNAs responsible for the synthesis of apocarotenoids and developmental processes during and after flowering. [ABSTRACT FROM AUTHOR]

The Orchidaceae is a mega-diverse plant family with ca. 29,000 species with a large variety of life forms that can colonize transitory habitats. Despite this diversity, little is known about their flowering integrators in response to specific environmental factors. During the reproductive transition in flowering plants a vegetative apical meristem (SAM) transforms into an inflorescence meristem (IM) that forms bracts and flowers. In model grasses, like rice, a flowering genetic regulatory network (FGRN) controlling reproductive transitions has been identified, but little is known in the Orchidaceae. In order to analyze the players of the FRGN in orchids, we performed comprehensive phylogenetic analyses of CONSTANS-like/CONSTANS-like 4 (COL/COL4), FLOWERING LOCUS D (FD), FLOWERING LOCUS C/FRUITFULL (FLC/FUL) and SUPRESSOR OF OVEREXPRESSION OF CONSTANS 1 (SOC1) gene lineages. In addition to PEBP and AGL24/SVP genes previously analyzed, here we identify an increase of orchid homologs belonging to COL4, and FUL gene lineages in comparison with other monocots, including grasses, due to orchid-specific gene lineage duplications. Contrariwise, local duplications in Orchidaceae are less frequent in the COL, FD and SOC1 gene lineages, which points to a retention of key functions under strong purifying selection in essential signaling factors. We also identified changes in the protein sequences after such duplications, variation in the evolutionary rates of resulting paralogous clades and targeted expression of isolated homologs in different orchids. Interestingly, vernalization-response genes like VERNALIZATION1 (VRN1) and FLOWERING LOCUS C (FLC) are completely lacking in orchids, or alternatively are reduced in number, as is the case of VERNALIZATION2/GHD7 (VRN2). Our findings point to non-canonical factors sensing temperature changes in orchids during reproductive transition. Expression data of key factors gathered from Elleanthus auratiacus, a terrestrial orchid in high Andean mountains allow us to characterize which copies are actually active during flowering. Altogether, our data lays down a comprehensive framework to assess gene function of a restricted number of homologs identified more likely playing key roles during the flowering transition, and the changes of the FGRN in neotropical orchids in comparison with temperate grasses. [ABSTRACT FROM AUTHOR]

Key message: MsTFL1A is an important gene involved in flowering repression in alfalfa (Medicago sativa) which conditions not only above-ground plant shoot architecture but also root development and growth. Delayed flowering is an important trait for forage species, as it allows harvesting of high-quality forage for a longer time before nutritional values decline due to plant architecture changes related to flowering onset. Despite the relevance of delayed flowering, this trait has not yet been thoroughly exploited in alfalfa. This is mainly due to its complex genetics, sensitivity to inbreeding and to the fact that delayed flowering would be only advantageous if it allowed increased forage quality without compromising seed production. To develop new delayed-flowering varieties, we have characterized the three TERMINAL FLOWERING 1 (TFL1) family of genes in alfalfa: MsTFL1A, MsTFL1B and MsTFL1C. Constitutive expression of MsTFL1A in Arabidopsis caused late flowering and changes in inflorescence architecture, indicating that MsTFL1A is the ortholog of Arabidopsis TFL1. Overexpression of MsTFL1A in alfalfa consistently led to delayed flowering in both controlled and natural field conditions, coupled to an increase in leaf/stem ratio, a common indicator of forage quality. Additionally, overexpression of MsTFL1A reduced root development, reinforcing the role of MsTFL1A not only as a flowering repressor but also as a regulator of root development.We conclude that the precise manipulation of MsTFL1A gene expression may represent a powerful tool to improve alfalfa forage quality. [ABSTRACT FROM AUTHOR]

Key message: 111 PHD genes were newly identified in rye genome and ScPHD5’s role in regulating cold tolerance and flowering time was suggested. Plant homeodomain (PHD)-finger proteins regulate the physical properties of chromatin and control plant development and stress tolerance. Although rye (Secale cereale L.) is a major winter crop, PHD-finger proteins in rye have not been studied. Here, we identified 111 PHD genes in the rye genome that exhibited diverse gene and protein sequence structures. Phylogenetic tree analysis revealed that PHDs were genetically close in monocots and diverged from those in dicots. Duplication and synteny analyses demonstrated that ScPHDs have undergone several duplications during evolution and that high synteny is conserved among the Triticeae species. Tissue-specific and abiotic stress-responsive gene expression analyses indicated that ScPHDs were highly expressed in spikelets and developing seeds and were responsive to cold and drought stress. One of these genes, ScPHD5, was selected for further functional characterization. ScPHD5 was highly expressed in the spike tissues and was localized in the nuclei of rye protoplasts and tobacco leaves. ScPHD5-overexpressing Brachypodium was more tolerant to freezing stress than wild-type (WT), with increased CBF and COR gene expression. Additionally, these transgenic plants displayed an extremely early flowering phenotype that flowered more than two weeks earlier than the WT, and vernalization genes, rather than photoperiod genes, were increased in the WT. RNA-seq analysis revealed that diverse stress response genes, including HSPs, HSFs, LEAs, and MADS-box genes, were also upregulated in transgenic plants. Our study will help elucidate the roles of PHD genes in plant development and abiotic stress tolerance in rye. [ABSTRACT FROM AUTHOR]

SQUAMOSA promoter binding-like proteins (SPLs) are important transcription factors that influence growth phase transition and reproduction in plants. SPLs are targeted by miR156 but the SPL/miR156 module is completely unknown in oat. We identified 28 oat SPL genes (AsSPLs) distributed across all 21 oat chromosomes except for 4C and 6D. The oat- SPL gene family represented six of eight SPL phylogenetic groups, with no AsSPLs in groups 3 and 7. A novel oat miR156 (AsmiR156) family with 21 precursors divided into 7 groups was characterized. A total of 16 AsSPLs were found to be targeted by AsmiR156. Intriguingly, AsSPL3s showed high transcript abundance during early inflorescence (GS-54), as compared to the lower abundance of AsmiR156, indicating their role in reproductive development. Unravelling the SPL/miR156 regulatory hub and alterations in expression patterns of AsSPLs could provide an essential toolbox for genetic improvement in the cultivated oat. [ABSTRACT FROM AUTHOR]

Background: Dendrocalamus strictus (Roxb.) Nees, generally referred to as 'Male bamboo,' is a globally prevalent and highly significant species of bamboo. It is a versatile species and possesses notable industrial significance. However, despite its numerous applications, the production of this plant is insufficient to fulfill the worldwide demand. The challenges that impede the dissemination of D. strictus encompass the unpredictable blooming pattern (30–70 years), low seed production, and limited seed viability. Therefore, tissue culture presents a reliable and effective option for the mass production of standardized planting material. Methodology and results: This study investigated the effects of silver nanoparticles (AgNPs) at a concentration of 6.0 mg L− 1 in the Murashige and Skoog (MS) nutrient medium fortified with pre-optimized plant growth regulators (3.0 mg L− 1 6-benzylaminopurine + 0.5 mg L− 1 α-naphthalene acetic acid) on the induction of flowering in a controlled environment in D. strictus. The use of AgNPs in the media induced a maximum of 14 inflorescences per culture vessel, 9 flowers per inflorescence, and improved the performance of the micropropagated plantlets during acclimatization in the greenhouse and field. The ISSR and SCoT amplified polymorphic DNA analysis of the regenerants resulted in the formation of 49 bands (300 to 2000 bp size) and 36 scorable bands (350 to 2000 bp) respectively. All the PCR amplicons produced by SCoT and ISSR were monomorphic confirming the genetic uniformity of the tissue cultured plants of D. strictus with the mother plant. Conclusions: It can be inferred that the incorporation of AgNPs during the shoot proliferation phase has the potential to stimulate in vitro flowering in D. strictus. This finding could provide valuable insights into innovative strategies for enhancing crop productivity and genetic manipulation for accelerated breeding and agricultural advancement. Key message: The utilization of silver nanoparticles in the nutrient medium significantly induced flowering in Dendrocalamus strictus, demonstrating the potential for plant breeding, enhancing crop productivity, and agricultural advancement through tissue culture techniques. [ABSTRACT FROM AUTHOR]

The MIKCC-type MADS-box gene family is involved in the regulation of fower development. A total of 109 members of the MIKCC-type MADS-box gene family were identifed in blueberry. According to the phylogenetic tree, these 109 MIKCC-type MADS-box proteins were divided into 13 subfamilies, which were distributed across 40 Scafolds. The results of the conserved motif analysis showed that among 20 motifs, motifs 1, 3, and 9 formed the MADS-box structural domain, while motifs 2, 4, and 6 formed the K-box structural domain. The presence of 66 pairs of fragment duplication events in blueberry suggested that gene duplication events contributed to gene expansion and functional diferentiation. Additionally, the presence of cis-acting elements revealed that VcFLC2, VcAG3, and VcSVP9 might have signifcant roles in the endo-dormancy release of fower buds. Meanwhile, under chilling conditions, VcAP3.1 and VcAG7 might facilitate fower bud dormancy release. VcSEP11 might promote fowering following the release of endo-dormancy, while the elevated expression of VcAP1.7 (DAM) could impede the endo-dormancy release of fower buds. The efect of gibberellin (GA4+7) treatment on the expression pattern of MIKCC-type MADS-box genes revealed that VcAP1.4, VcAP1.6, VcAP3.1, VcAG3, and VcFLC2 might promote fower bud endo-dormancy release, while VcAP3.2, VcSEP11, and VcSVP9 might inhibit its endo-dormancy release. These results indicated that VcAP1.4, VcAP1.6, VcAP1.7 (DAM), VcAP3.1, VcAG3, VcAG7, VcFLC2, and VcSVP9 could be selected as key regulatory promoting genes for controlling the endo-dormancy of blueberry fower buds. [ABSTRACT FROM AUTHOR]

Key message: PnNAC2 positively regulates saponin biosynthesis by binding the promoters of key biosynthetic genes, including PnSS, PnSE, and PnDS. PnNAC2 accelerates flowering through directly associating with the promoters of FT genes. NAC transcription factors play an important regulatory role in both terpenoid biosynthesis and flowering. Saponins with multiple pharmacological activities are recognized as the major active components of Panax notoginseng. The P. notoginseng flower is crucial for growth and used for medicinal and food purposes. However, the precise function of the P. notoginseng NAC transcription factor in the regulation of saponin biosynthesis and flowering remains largely unknown. Here, we conducted a comprehensive characterization of a specific NAC transcription factor, designated as PnNAC2, from P. notoginseng. PnNAC2 was identified as a nuclear-localized protein with transcription activator activity. The expression profile of PnNAC2 across various tissues mirrored the accumulation pattern of total saponins. Knockdown experiments of PnNAC2 in P. notoginseng calli revealed a significant reduction in saponin content and the expression level of pivotal saponin biosynthetic genes, including PnSS, PnSE, and PnDS. Subsequently, Y1H assays, dual-LUC assays, and electrophoretic mobility shift assays (EMSAs) demonstrated that PnNAC2 exhibits binding affinity to the promoters of PnSS, PnSE and PnDS, thereby activating their transcription. Additionally, an overexpression assay of PnNAC2 in Arabidopsis thaliana witnessed the acceleration of flowering and the induction of the FLOWERING LOCUS T (FT) gene expression. Furthermore, PnNAC2 demonstrated the ability to bind to the promoters of AtFT and PnFT genes, further activating their transcription. In summary, these results revealed that PnNAC2 acts as a multifunctional regulator, intricately involved in the modulation of triterpenoid saponin biosynthesis and flowering processes. [ABSTRACT FROM AUTHOR]

Pigeon pea is an important protein-rich pulse crop. Identification of flowering master regulators in pigeon pea is highly imperative as indeterminacy and late flowering are impediments towards yield improvement. A genome-wide analysis was performed to explore flowering orthologous groups in pigeon pea. Among the 412 floral orthologs identified in pigeon pea, 148 genes belong to the meristem identity, photoperiod-responsive, and circadian clock–associated ortholog groups. Our comparative genomics study revealed purifying selection pressures (ka/ks) on floral orthologs, and duplication patterns and evolution through synteny with other model species. Phylogenetic analysis of floral genes substantiated a connection between pigeon pea plant architecture and flowering time as all the PEBP domain–containing genes belong to meristem identity floral networks of pigeon pea. Expression profiling of eleven major orthologs in contrasting determinate and indeterminate genotypes indicated that these orthologs might be involved in flowering regulation. Expression of floral inducer, FT, and floral repressor, TFL1, was non-comparable in indeterminate genotypes across all the developmental stages of pigeon pea. However, dynamic FT/TFL1 expression ratio detected in all tissues of both the genotypes suggested their role in floral transition. One TFL1 ortholog having high sequence conserveness across pigeon pea genotypes showed differential expression indicating genotype-dependent regulation of this ortholog. Presence of conserved 6mA-methylation patterns in light-responsive elements and in other cis-regulatory elements of FT and TFL1 across different plant genotypes indicated possible involvement of epigenetic regulation in flowering. [ABSTRACT FROM AUTHOR]

Phenophase durations, including the timing of flowering and ripeness, were characterized in 20 inbred lines of the maize Zea mays L. Expression of key flowering initiation genes (CONZ1, GIGZ1a, GIGZ1b, ZmFKF1a, and ZmFKF1b) under long-photoperiod conditions was studied in seedlings of six maize lines that differed in ripeness time. Significantly lower transcription levels of all of the five genes were found in early-ripening lines compared with late-ripening lines. Similar expression patterns were observed for the GIGZ1a and GIGZ1b paralogous genes, while ZmFKF1a significantly predominated in expression over its paralog ZmFKF1b. [ABSTRACT FROM AUTHOR]

Veronica nakaiana Ohwi is a Korean endemic species and has potential value as an ornamental and breeding resource of Veronica species. Therefore, it is necessary to determine the environmental factors for floral induction to manipulate flowering for the industrial application of this plant. This study was conducted to investigate the flowering response of V. nakaiana to cold temperatures and photoperiod treatments. In Expt. 1, six-week-old seedlings were treated with a cold temperature of 5 °C for from 0 to 12 weeks. After the artificial cold treatments, the plants were subjected to the following photoperiod treatments: 9/15, 12/12, 14/10, 16/8, or 24/0 (day/night) h. In Expt. 2, seven-month-old plants were transferred to an open field for natural cold treatments and the chilling hours were calculated to quantify the flowering response to cold temperatures. In Expt. 1, the photoperiod does not affect the percent flowering or flowering time. The plants flowered only after artificial cold treatments lasting for more than eight weeks. However, the average percent flowering was less than half. In Expt. 2, although flowering was also observed only after more than eight weeks of natural cold treatment, the percent flowering in Expt. 2 was higher than that in Expt. 1. In both experiments, the number of days to flowering significantly decreased with increasing the cold treatment period. These results indicated that V. nakaiana is a day-neutral plant and requires a prolonged period of cold temperatures. In addition, the cold requirement showed an age-dependent response on flowering. [ABSTRACT FROM AUTHOR]

Despite the great economic benefits, one of the major threats of introducing species into exotic ranges is their ability to regenerate and spread to novel environments. For example, Eucalyptus globulus plantations have been established in many parts of the world, using seedlings or clonal material, the latter often from advanced generation tree improvement programs. However, major concerns exist about this species' ability to invade non-native areas. Therefore, it is necessary to study whether breeding programs affect this species' reproductive biology to assess the risk of invasiveness of these improved trees. In this sense, this work compared the E. globulus phenological behaviour and reproductive structures production of three clonal and one seedling-based stand across two distinct climatic zones (mesic and xeric) in Portugal. Through binocular observation, four different stands (seedlings descending from open-pollinated crosses and three clonal-stands) were monitored every three weeks for different reproductive phenological stages, namely the presence of flowers and capsules. Clonal stands presented a shorter flowering season, less abundant reproductive structures, and higher phenological variability across sites than seedling-based stands. Phenological patterns and fructification abundance also varied between the three clonal stands. These results suggest that clones with decreased reproductive ability can be chosen during the breeding process, lowering the dispersal risk while enhancing productivity. Thus, understanding the phenological behaviour of E. globulus is critical to more sustainable agroforestry by reducing the spread risks. [ABSTRACT FROM AUTHOR]

Efforts to enrich the varietal wealth in litchi with desired cultivars have been attempted. At ICAR-NRCL hybridization efforts have been emphasized for the past decades. The observed characteristic features and constraints encountered during the period were identified and systematic observations were taken. Studies show that the low genetic variability, small window of flowering period and stigma receptivity, small flower size, panicle injury, high flower and fruit drop, low seed germination and survivability are the prime hurdle that needs to be addressed. On average, the flowering period reported is 10–14 days which is even shorter during periods of increasing weather temperature. Across cultivars, the effective pollination period is very narrow and coincidence of stigma receptivity among cultivars was observed making it very challenging to attempt a maximum number of crosses within a short period. It was also observed that large numbers of small-sized and delicate flowers are produced in a panicle which injure the panicles during thinning and emasculation. Less than 3% of pollinated flowers were observed to attain fruit set which also registered low fruit retention during subsequent fruit development. The attack of seed borer at both the early and mature stages of fruit growth was noted which rendered the seeds non-viable. Parent incompatibility and very low success rate of hybrid seedling establishment were also observed especially in crosses involving small seeded parents like 'Bedana'. Here we present findings from a decade of experimentation on hybridization in litchi and document hurdles that come in the way of developing hybrids in litchi. Such information will be crucial for devising strategies for an effective litchi breeding programme. [ABSTRACT FROM AUTHOR]

CUP-SHAPED COTYLEDON (CUC) transcription factors have a central regulatory function in plant growth and development. However, their involvement in kenaf (Hibiscus cannabinus L.) remains largely unexplored. In this study, we conducted a comprehensive analysis to identify six HcCUC genes in the kenaf genome. Through bioinformatic analysis, we found that the kenaf HcCUC genes share similar motifs and highly conserved gene structures. Phylogenetic analysis categorized the six HcCUC genes into two groups, that shared similarities with CUC2 or CUC3 genes from other species. Collinearity analysis revealed the formation of 6 syntenic gene pairs among the HcCUC genes, and 8 homologous gene pairs with three AtCUC genes from Arabidopsis. To investigate tissue-specific expression, we analyzed transcriptome data, that showed differential expression of HcCUC genes, particularly in leaves during the seedling stage, buds during the maturation stage, and anthers at the dual-core period. Functional characterization of HcCUC1 was achieved through its overexpression in Arabidopsis, resulting in elongated cotyledons, absent of petioles and increased number of rosette leaf and lateral branches. qRT-PCR analysis revealed that HcCUC1 potentially influences leaf and lateral branch development by up-regulating the expression of auxin-related genes (AtYUC2, AtYUC4, AtPIN1, AtPIN3, AtPIN4) and leaf shape-related genes (AtKNAT2, AtKNAT6). Notably, overexpression of HcCUC1 down-regulated the expression of flowering-related genes (AtFT, AtAP1, AtLFY, AtFUL), causing delayed flowering. Overall, our findings emphasize the pivotal role of HcCUC1 in regulating leaf and lateral branch growth, development, and flowering time, provide valuable insights into the function and genetic regulation of HcCUC genes. Key message: Six HcCUC genes were identified in the kenaf genome, with HcCUC1 playing a role in regulating leaf and lateral branch growth and development, as well as flowering time. [ABSTRACT FROM AUTHOR]

SWR1 chromatin remodeling complex (SWR1-C) plays a crucial role in gene regulation during growth and development of eukaryotes. ACTIN-RELATED PROTEIN 6 (ARP6), an essential subunit of SWR1-C, is implicated in flowering and stress response. However, the functions of pineapple ARP6 have not been investigated, which limits its potential use in molecular breeding. Here, pineapple ARP6 is functionally characterized and its role in flowering, salt stress, drought, nutrient deficiency and immunity is verified. Phylogenetic analysis showed that AcARP6 is homologous to ARP6 of rice and Arabidopsis. Expression analysis revealed that AcARP6 gets induced by salt, osmotic and nutrient deficiency. Additionally, ectopic expression of AcARP6 in Arabidopsis delayed flowering and increased tolerance to salinity, drought and nutrient deficiency, but displayed sensitivity against Sclerotinia sclerotiorum infection. Furthermore, AcARP6 complemented the phenotypic defects of the arp6 mutation in Arabidopsis. These results provide evidence for the involvement of AcARP6 in multiple stress responses and advocate that AcARP6 could be used as a potential candidate gene for improving tolerance against abiotic stresses. [ABSTRACT FROM AUTHOR]

The Arctic is warming at an alarming rate. While changes in plant community composition and phenology have been extensively reported, the effects of climate change on reproduction remain poorly understood. We quantified multidecadal changes in flower density for nine tundra plant species at a low- and a high-Arctic site in Greenland. We found substantial changes in flower density over time, but the temporal trends and drivers of flower density differed both between species and sites. Total flower density increased over time at the low-Arctic site, whereas the high-Arctic site showed no directional change. Within and between sites, the direction and rate of change differed among species, with varying effects of summer temperature, the temperature of the previous autumn and the timing of snowmelt. Finally, all species showed a strong trade-off in flower densities between successive years, suggesting an effective cost of reproduction. Overall, our results reveal region- and taxon-specific variation in the sensitivity and responses of co-occurring species to shared climatic drivers, and a clear cost of reproductive investment among Arctic plants. The ultimate effects of further changes in climate may thus be decoupled between species and across space, with critical knock-on effects on plant species dynamics, food web structure and overall ecosystem functioning. [ABSTRACT FROM AUTHOR]

MADS-box family genes play an important role in the development of plant reproductive growth, but there have been no genome-wide characterization reports on Isatis indigotica Fortune. In this study, eighty IiMADS genes were identified and clustered into 16 subgroups (3 type I and 13 type II) with reference to Arabidopsis MADS genes. Most IiMADS proteins in the same cluster had similar exon-intron and motif structures. Seventy-four IiMADS genes were randomly distributed among 7 chromosomes, and the remaining genes were contigs. The RNA-seq data showed that most IiMADS transcripts were highly enriched in roots, stems, flowers and fruits but rarely in leaves. Based on our phylogenetic and expression analyses, the IiSVP gene from I. indigotica was cloned and functionally characterized. qRT-PCR revealed that IiSVP is mainly expressed in stems, buds, flowers, and fruits. The IiSVP protein could interact with IiSOC1 and IiFLC, which was detected by BiFC and Y2H. The heterogeneous overexpression of IiSVP in Arabidopsis showed that it suppresses floral organ development, delays flowering and is significantly related to the expression of flowering genes such as FLC, SOC1 and GA20ox2. This study provided new information on the MADS family in I. indigotica and suggested that IiSVP is a key gene in suppressing flowering in I. indigotica. [ABSTRACT FROM AUTHOR]

Characterizing airborne pollen concentrations is crucial for supporting allergy and asthma management; however, pollen monitoring is labor intensive and, in the USA, geographically limited. The USA National Phenology Network (USA-NPN) engages thousands of volunteer observers in regularly documenting the developmental and reproductive status of plants. The reports of flower and pollen cone status contributed to the USA-NPN's platform, Nature's Notebook, have the potential to help address gaps in pollen monitoring by providing real-time, spatially explicit information from across the country. In this study, we assessed whether observations of flower and pollen cone status contributed to Nature's Notebook can serve as effective proxies for airborne pollen concentrations. We compared daily pollen concentrations from 36 National Allergy Bureau (NAB) stations in the USA with flowering and pollen cone status observations collected within 200 km of each NAB station in each year, 2009–2021, for 15 common tree taxa using Spearman's correlations. Of 350 comparisons, 58% of correlations were significant (p < 0.05). Comparisons could be made at the largest numbers of sites for Acer and Quercus. Quercus demonstrated a comparatively high proportion of tests with significant agreement (median ρ = 0.49). Juglans demonstrated the strongest overall coherence between the two datasets (median ρ = 0.79), though comparisons were made at only a small number of sites. For particular taxa, volunteer-contributed flowering status observations demonstrate promise to indicate seasonal patterns in airborne pollen concentrations. The quantity of observations, and therefore, their utility for supporting pollen alerts, could be substantially increased through a formal observation campaign. [ABSTRACT FROM AUTHOR]

The production of fertile inflorescences is essential to make crosses for the development of new varieties of sugarcane. Within the Saccharum species and commercial hybrids of sugarcane, there is a wide range in flowering times and some varieties rarely flower; this can make it impossible to achieve some desired crosses. While photoperiod houses can assist with inducing some varieties to flower or synchronise flowering, understanding the expression of genes within the flowering pathway could provide an explanation for such variation. To this end experiments were designed to assess the photoperiod conditions within a controlled environment facility and measure changes in expression of 18 genes associated with flowering during the initial four weeks of the floral induction period at three time points across the day-light cycle. Two sugarcane varieties were selected for their differences in flowering propensity, Q208 and Q183, flowering and non-flowering, respectively. The 18 genes examined were associated with photoperiod perception, the circadian clock, the floral pathway, and floral meristem identity. Of these, 16 were detected and showed differences in expression during the light cycle and over the 4 weeks under photoperiod induction in Q208. The assessment of a subset of those genes in Q183 showed higher expression levels of ShLHY, ShCO and ShTFL1 in Q183 than Q208. One of the genes, TFL1 is a known flowering inhibitor of the penultimate step prior to floral induction. These gene profiles build on the proposed sugarcane flowering pathway and highlight key genes for manipulation to promote and synchronise flowering to assist sugarcane breeding programmes. [ABSTRACT FROM AUTHOR]

In flowering plants, FLOWERING LOCUS T (FT) and TERMINAL FLOWER 1 (TFL1), members of the phosphatidylethanolamine-binding protein (PEBP) family, are key players in flowering control with antagonistic functions: FT promotes flowering, while TFL1 represses it. Here, we report the functional characterization of FT/TFL1-like (FTL) genes from Pinus densiflora (PdeFTL1 and PdeFTL2). Sequence analysis showed that both PdeFTL1 and PdeFTL2 had a conserved PEBP domain with several specific amino acid residues characteristic of TFL1 function, including Serine (S) at position 137, which is Tryptophan (W) in FT function. We generated a chimeric gene of PdeFTL1_S137W and tested its floral regulatory function by heterologous expression in tobacco and Arabidopsis. Our results showed that tobacco plants transiently expressing PdeFTL1_S137W significantly accelerate flowering time. Likewise, transgenic Arabidopsis overexpressing PdeFTL1_S137W produced flower buds at a very immature stage with only 3–5 true leaves, similar to 35S::AtFT plants. However, 35S::PdeFTL1 plants showed a mild delay in flowering compared to the control. Collectively, our molecular evolution study successfully demonstrated that substituting only one amino acid of the PdeFTL1 protein could completely change the biochemical activity of this protein to a floral activator. Therefore, this strategy can be utilized as a basis to modulate flowering time in conifers. [ABSTRACT FROM AUTHOR]

Adaptation to temporal stress can be achieved by modifying flowering time and lengthening the reproductive period. To identify genotypes, molecular markers, and genes related with these traits, a set of 94 soybeans were genotyped using 7125 SNPs and 6465 DArTs. The genotypes were grouped according to their duration cycle (cycle) and were analyzed, days from emergence to beginning bloom (E–R1), days from beginning bloom to beginning pod (R1–R3), and days from beginning pod to full seed (R3–R6), identifying fifty-six genotypes with short E–R1 (Sh.E–R1) and/or prolonged R1–R3 and R3–R6 (L.R1–R3 and L.R3–R6). The population structure determined with 14 SSR markers that best adjusted was K = 2. For a total of 203 markers associated with Sh.E–R1, L.R1–R3, and L.R3–R6, 1221 candidate genes were identified, of which 17 were previously cited and/or containing markers located in their sequence and were selected for future studies. Splitting the reproductive period in two phases allowed the detection of variability through it. It was verified the existence of genotypes with early bloom and/or prolonged reproductive period within germplasm with similar cycle. The genotypes identified, molecular markers, and associated genes can be used in breeding programs to extend the reproductive period in soybean. [ABSTRACT FROM AUTHOR]

In order to study the molecular regulation mechanism of floral transition in Phalaenopsis (Orchidaceae), especially in the hormone signal transduction pathway, the transcriptome of 5 flower developing stages in Phalaenopsis was sequenced, yielding 63 368 unigenes, including 28 339 differentially expressed genes (DEGs). In result, flowering genes were identified, including flower organ identity genes, floral integrator pathway genes, floral meristem identity genes, vernalization pathway genes, age pathway gene, gibberellin (GA) pathway genes, autonomous pathway genes and photoperiod pathway genes. The key genes in plant hormone signal transduction were screened and validated by qRT-PCR. Those genes, including AP1, PIF4X, FT, and TAA2, were highly expressed in the flower bud during the flower initiation and differentiation phases, while GA2ox and PIF4 had lower expression in the flower bud but high expression in the root. The expression of DELLA was up-regulated in the flower bud and down-regulated in the roots; by contrast, the expression of GA2ox was down-regulated in the flower bud and up-regulated in the roots. PIF4 gene expression was remarkably up-regulated in flower stalk, leaves, and roots after spray treatment with GA3 (8.66 × 10–4 mol/L), indicating that PIF4 may be a key gene that directly responds to gibberellin to promote flower initiation. [ABSTRACT FROM AUTHOR]

Biochar can affect plant growth and development, but how biochar affects flowering is unknown. To study the effects of biochar in soil on Arabidopsis (Arabidopsis thaliana L. (Heynh.)) flowering, rice husk biochar was prepared at three pyrolysis temperatures (350, 500, 650°C) and two residence times (1 and 2 h). Nutrient elements and organic compounds were measured in different biochars. Biochar leachates were also obtained. Arabidopsis flowering times, vegetative and reproductive growth, photoperiod pathway and the gibberellin 3 (GA3) pathway-related gene expression, and endogenous GA3 were measured. Different biochars had different types of nutrient elements and organic compounds. Compared without biochar, biochars prepared at higher pyrolysis temperatures (500 and 650°C) and a longer residence time (2 h) led to earlier flowering, increases in vegetative and reproductive growth, higher expression levels of photoperiod and GA3 pathway-related genes, and higher endogenous GA3 content. Arabidopsis treated with biochar prepared at 500°C for 2 h was the first to flower. Biochar leachates had slightly different effects from those of biochar, but those from biochar prepared at 350°C for 1 h and 500°C for 1 or 2 h also promoted flowering. The organic compounds contained in biochar can promote flowering in Arabidopsis. Biochar prepared under different conditions contained different organic compounds and therefore also had different influences on flowering. One of the reasonable mechanisms for biochar-promoted flowering in Arabidopsis was the upregulated expression of downstream gene APETALA1 (AP1) in the photoperiod and the GA3 pathways. [ABSTRACT FROM AUTHOR]

Impact of climate change affects chilling and heat accumulation that phenological development of plant needs, air temperature being determinant for flowering, pollination and fruit production, but few knowledges are available in the winter and spring climate of Tétouan. The physiological mechanisms of the reproductive cycle that controls pollen emission are related with temperature, and different environmental factors regulate strongly the reproductive phases of the plant's life cycle. However, from an empirical point of view, the alternance between endodormancy and ecodormancy is not well detectable. Our work focuses on determining the heat accumulation periods associated with the thermal balance needed to fulfill the chilling and heat required for budbreak and bloom timing. To evaluate Morus, Pistacia, Quercus and Olea response to changes in chill and heat accumulation rates, the Dynamic Model and the Growing Degree-Days Method were used. Regression analyses identified the chilling and forcing periods for these taxa. Over the past 12 years, chill accumulation during tree dormancy increased significantly for most of woody taxa studied, while heat accumulation decreased not significantly for all taxa. Heat accumulation was the main driver of bloom timing, with effects of variation in chill accumulation. [ABSTRACT FROM AUTHOR]

Key message: T-DNA and CRISPR/Cas9-mediated knockout of polyester synthase-like genes delays flowering time in Arabidopsis thaliana and Medicago sativa (alfalfa). Thus, we here present the first report of edited alfalfa with delayed flowering. [ABSTRACT FROM AUTHOR]

Flowering is a crucial phase for angiosperms to continue their species propagation and is highly regulated. In the current review, flowering in sugarcane and the associated mechanisms are elaborately presented. In sugarcane, flowering has two effects, wherein it is a beneficial factor from the breeder's perspective and crucial for crop improvement, but commercially, it depletes the sucrose reserves from the stalks; hence, less value is assigned. Different species of Saccharum genus are spread across geographical latitudes, thereby proving their ability to grow in multiple inductive daylengths of different locations according in the habituated zone. In general, sugarcane is termed an intermediate daylength plant with quantitative short-day behaviour as it requires reduction in daylength from 12 h 55 min to 12 h or 12 h 30 min. The prime concern in sugarcane flowering is its erratic flowering nature. The transition to reproductive stage which reverts to vegetative stage if there is any deviation from ambient temperature and light is also an issue. Spatial and temporal gene expression patterns during vegetative to reproductive stage transition and after reverting to vegetative state could possibly reveal how the genetic circuits are being governed. This review will also shed a light on potential roles of genes and/or miRNAs in flowering in sugarcane. Knowledge of transcriptomic background of circadian, photoperiod, and gibberellin pathways in sugarcane will enable us to better understand of variable response in floral development. [ABSTRACT FROM AUTHOR]

Flowering determines the yield of saffron, whereas synchronized sprouting determines plant fitness; thus, their regulation is of utmost importance. In saffron, corm sprouting is marked with the emergence of flowers and leaves simultaneously. PEBP genes have a conserved role in regulating flowering and vegetative growth in plants, but their role in saffron is confined due to the non-availability of genomic resources. In the present study, we isolated their homologues in saffron and examined their alleged role in promoting flowering. Here we report that at least 6 FTs (FLOWERING LOCUS T), 2 TFL1s (TERMINAL FLOWER 1), and 2 MFTs (MOTHER OF FT AND TFL1) genes are present in saffron. The sequence analysis suggests they possess a conserved structural genetic organization with other plant species gene members. Interestingly, two FT genes (CsatFT4 and CsatFT6) showed the presence of characteristic amino acids of TFL-like genes but were aligned in FT genes clade. Phylogenetic analysis divided them into FT-like, TFL1-like, and MFT-like clades. The expression of identified genes varied among different tissues. The spatial and temporal expressions during sprouting suggest that they might have different functions. Tissue and organ-specific expression profiling suggest that CsatFT3 might act locally in apical buds to promote flowering, while CsatFT1 and 2 are involved in promoting vegetative growth. Antagonistically, CsatTFL1-1 and CsatTFL1-2 might regulate vegetative growth and flowering, respectively. Additionally, comparative expression profiling between flowering competent (big) vs non-competent (small) corms affirm the specific role of CsatFT3 as a plausible flowering regulator. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the effects of various light qualities of light emitting diodes (LEDs) on the growth, quality, chlorophyll fluorescence, and phytohormones of tulip 'Lasergame' in a closed-type plant factory system. After planting the tulip bulbs, LEDs of red, green, blue, white, and red + green + blue mixed (RGB) light were used for cultivation. The growth and quality of cut flowers were investigated, and various parameters were calculated by examining the chlorophyll fluorescence response. In addition, the contents of gibberellic acid (GA), indole-3-acetic acid (IAA), and abscisic acid (ABA) in the stem were analyzed to investigate the changes in phytohormones according to various light qualities. Cut flower length and internode length were observed to be longer under green and blue light than under red or RGB light. The ratio of leaf length to width was higher under green and blue light than under other treatments. In particular, the ornamental value was higher as the leaves were more upright under green light than under other treatments. However, there were no significant differences between the treatments in terms of the number of leaves, stem diameter, and days to harvesting. In holding solution after harvesting cut flowers, the cut flower length was the shortest under red and RGB light treatments at full bloom. The vase life of cut flowers was not significantly affected by the light quality. In the OJIP curve based on LED light qualities, the values of FJ, FI, and FP were higher under green light than under other treatments. Additionally, the values of ABS/CS, TRo/CS, and ETo/CS fluorescence parameters were higher under green light than under other treatments, and the values of Fv/Fo, Fv/Fm, ETo/TRo, and ETo/ABS fluorescence parameters appeared lowest under red light. Fourteen days after bulb planting, the GA3 and IAA contents in the stem were higher under green light than under RGB light, and the ABA content was higher under RGB light than under green light. Therefore, in the tulip 'Lagergame', it was found that the photosynthetic apparatus of photosystem II was operating more efficiently under green light than under other LED lights through the observation of the chlorophyll fluorescence reaction. These results support the notion that green light in a closed-type plant factory system improves the growth of cut flowers by promoting the biosynthesis of GA3 and IAA while inhibiting ABA biosynthesis. [ABSTRACT FROM AUTHOR]

The phenological response to climate change differs among species. We examined the beginning of flowering of the common snowdrop (Galanthus nivalis) in connection with meteorological variables in Czechia in the period 1923–2021. The long-term series were analyzed from phenological and meteorological stations of the Czech Hydrometeorological Institute (CHMI). Temporal and spatial evaluation (using Geographic Information System) in timing of beginning of flowering (BBCH 61) of G. nivalis was investigated under urban and rural settings. Furthermore, the detailed analysis of selected meteorological variables to onset of G. nivalis flowering was performed. Moreover, the trends (using Mann–Kendall test) and Pearson's correlation coefficients between phenological phase and meteorological variable were calculated. The main finding of this study was that the trend of the beginning of flowering of the common snowdrop during the studied period (1923–2021) is negative, and it varies in urban and rural environments. The results showed most significant acceleration of the beginning of flowering of G. nivalis by − 0.20 day year−1 in urban area and by − 0.11 day year−1 in rural area. Above that, a major turning point occurred between 1987 and 1988 (both, in phenological observations and meteorological variables), and the variability of the beginning of flowering is significantly higher in the second period 1988–2021. On top of, the study proved that the beginning of flowering of G. nivalis closely correlated with number of days with snow cover above 1 cm (December–March) at both types of stations (urban and rural), and with mean air temperature in February, maximum air temperature in January, and minimum air temperature in March. The Mann–Kendall test showed a reduction in the number of days with snow cover above 1 cm (December–March) during 99 years period at Klatovy station (a long-term time series) by − 0.06 day year−1, i.e., by − 5.94 days per the whole period. Conversely, air temperatures increase (maximum and minimum air temperature by 0.03 °C year−1 (2.97 °C per the whole period) and average air temperature by 0.02 °C year−1 (1.98 °C per the whole period)). Thus, our results indicate significant changes in the beginning of flowering of G. nivalis in Czechia as a consequence of climate change. [ABSTRACT FROM AUTHOR]

Background: CO and FT, two major components in the photoperiod pathway, and FLOWERING LOCUS C (FLC), a MADS-box transcription factor of vernalization, play a pivotal role in controlling Arabidopsis flowering time. Many B-box-containing proteins have been reported to regulate flowering time through CO-dependence or independence.Here, we clarified that B-box transcription factor 29 (BBX29) interacts with CONSTANS (CO) and represses FLOWERING LOCUS T (FT) and SUPPRESSOR OF OVEREXPRESSION OF CO 1 (SOC1) expression. Overexpressing BBX29 showed a late-flowering phenotype in Arabidopsis by reducing the FT transcript level and enhancing FLC expression under long and short days. BBX29 does not affect CO transcription. The interaction of BBX29-CO may condense CO distribution in nuclei. The bbx29 mutants showed early flowering under long days but not short days. The early flowering was correlated with the upregulation of FT expression.Together with our data, BBX29 plays an essential role in photoperiod and FLC regulation. Our results should provide insight into BBX29 functions in the flowering of Arabidopsis.Results: CO and FT, two major components in the photoperiod pathway, and FLOWERING LOCUS C (FLC), a MADS-box transcription factor of vernalization, play a pivotal role in controlling Arabidopsis flowering time. Many B-box-containing proteins have been reported to regulate flowering time through CO-dependence or independence.Here, we clarified that B-box transcription factor 29 (BBX29) interacts with CONSTANS (CO) and represses FLOWERING LOCUS T (FT) and SUPPRESSOR OF OVEREXPRESSION OF CO 1 (SOC1) expression. Overexpressing BBX29 showed a late-flowering phenotype in Arabidopsis by reducing the FT transcript level and enhancing FLC expression under long and short days. BBX29 does not affect CO transcription. The interaction of BBX29-CO may condense CO distribution in nuclei. The bbx29 mutants showed early flowering under long days but not short days. The early flowering was correlated with the upregulation of FT expression.Together with our data, BBX29 plays an essential role in photoperiod and FLC regulation. Our results should provide insight into BBX29 functions in the flowering of Arabidopsis.Conclusions: CO and FT, two major components in the photoperiod pathway, and FLOWERING LOCUS C (FLC), a MADS-box transcription factor of vernalization, play a pivotal role in controlling Arabidopsis flowering time. Many B-box-containing proteins have been reported to regulate flowering time through CO-dependence or independence.Here, we clarified that B-box transcription factor 29 (BBX29) interacts with CONSTANS (CO) and represses FLOWERING LOCUS T (FT) and SUPPRESSOR OF OVEREXPRESSION OF CO 1 (SOC1) expression. Overexpressing BBX29 showed a late-flowering phenotype in Arabidopsis by reducing the FT transcript level and enhancing FLC expression under long and short days. BBX29 does not affect CO transcription. The interaction of BBX29-CO may condense CO distribution in nuclei. The bbx29 mutants showed early flowering under long days but not short days. The early flowering was correlated with the upregulation of FT expression.Together with our data, BBX29 plays an essential role in photoperiod and FLC regulation. Our results should provide insight into BBX29 functions in the flowering of Arabidopsis. [ABSTRACT FROM AUTHOR]

Tagetes patula L. is a prominent plant that is frequently used for its ornamental value. Marigolds are sources of various compounds of great interest to agricultural, pharmaceutical, and nutritional industries. Microalgae can be applied as a biostimulant as they have multifunctional properties in agriculture, namely facilitating nutrient uptake, improving crop performance and physiological status, and thus increasing tolerance to abiotic stress. This study evaluated the effect of applying Chlorella vulgaris as a plant biostimulant on the growth and flowering of T.patula plants. Microalgae suspensions were applied to the substrate at concentrations of 0.5, 2.0 and 5.0 g dry weight (DW) L−1. A set of plants without the application of microalgae was used as control. The use of microalgae had a positive impact on plant growth. Specifically, C. vulgaris application resulted in greater height, while the highest concentration (5.0 g DW L−1) resulted in higher fresh weight. Microalgae application significantly promoted the earlier flowering of marigolds. The macronutrient and micronutrient values were statistically similar between the control plants and those treated with microalgae. When considering only the treated plants, there was a significant correlation between the concentration of C. vulgaris and the concentrations of N, P, Mn and Cu in the shoots of T.patula plants. Plants receiving higher concentrations of C. vulgaris exhibited higher levels of these nutrients. These results highlight the potential use of Chlorella vulgaris as an effective biostimulant for enhancing the growth, flowering, and nutrient uptake of T.patula, offering valuable applications for improving ornamental plant production and, ultimately, agricultural sustainability. [ABSTRACT FROM AUTHOR]

Key message: Auxin accumulation upregulates the expression of APETALA1 (CmAP1) and subsequently activates inflorescence primordium development in axillary buds of chestnut. The architecture of fruiting branches is a key determinant of chestnut yield. Normally, axillary buds at the top of mother fruiting branches develop into flowering shoots and bear fruits, and the lower axillary buds develop into vegetative shoots. Decapitation of the upper axillary buds induces the lower buds to develop into flowering shoots. How decapitation modulates the tradeoff between vegetative and reproductive development is unclear. We detected inflorescence primordia within both upper and lower axillary buds on mother fruiting branches. The level of the phytohormones 3-indoleacetic acid (IAA) and trans-zeatin (tZ) increased in the lower axillary buds in response to decapitation. Exogenous application of the synthetic analogues 1-naphthylacetic acid (NAA) or 6-benzyladenine (6-BA) blocked or promoted, respectively, the development of the inflorescence primordia in axillary buds. The transcript levels of the floral identity gene CmAP1 increased in axillary buds following decapitation. An auxin response element TGA-box is present in the CmAP1 promoter and influenced the CmAP1 promoter-driven expression of β-glucuronidase (GUS) in floral organs in Arabidopsis, suggesting that CmAP1 is induced by auxin. We propose that decapitation releases axillary bud outgrowth from inhibition caused by apical dominance. During this process, decapitation-induced accumulation of auxin induces CmAP1 expression, subsequently promoting the reproductive development of axillary buds. [ABSTRACT FROM AUTHOR]

Cocoa-based agroforests are promoted to replace monocultures for the provision of ecosystem services. However, shade tree pruning, an important tool to sustain cocoa yields, is not commonly implemented. This study investigates the effect of pruning on both agronomic and economic performance. In Bolivia, four famers' sites were divided in half, and shade trees pruned in one of the two plots. Pruning resulted in a significant increase in cocoa yield, from an average of 430 to 710 kg ha−1 by boosting flowering and pod production, but not reducing the proportion of damaged pods, and of those lost to cherelle wilt. Additionally, scenario calculations using international and organic premium cocoa prices were conducted to evaluate the economic feasibility of pruning. The minimum, mean and maximum yield of 22 local cocoa-based agroforestry farms were used as reference for 25, 50 and 75% yield increase scenarios. Offsetting the pruning costs highly depended on the initial yield levels. Using the minimum yield, all scenarios led to a lower net income compared with no pruning. For the mean yield level, the net income was equal to that obtained without pruning when the yield increase was above 51%. At the maximum yield level, all increase scenarios resulted in a higher net income. Our results prove the importance of pruning agroforestry trees to increase cocoa yields. However, with current farm-gate prices for cocoa, farmers alone cannot cover the extra management costs. The cocoa sector should discuss different strategies to support pruning for a broader adoption of agroforests. [ABSTRACT FROM AUTHOR]

Key message: OsiCRY2 is involved in light-regulated plant development and plays a role in regulating photomorphogenesis, plant height, flowering and most strikingly partial photomorphogenesis in dark. Cryptochrome 2 (CRY2), the blue/UV-A light photoreceptor in plants, has been reported to regulate photoperiod-dependent flowering and seedling photomorphogenesis (under low-intensity light). Among monocots, CRY2 has been reported from japonica rice, wheat, sorghum and barley. The two sub-species of rice, indica and japonica, exhibit a high degree of genetic variation and morphological and physiological differences. This article describes the characterization of CRY2 of indica rice (OsiCRY2). While the transcript levels of OsiCRY2 did not change significantly under blue light, its protein levels were found to decline with increased time duration under blue light. For phenotypic characterization, OsiCRY2 over-expression (OX) transgenics were generated in Oryza sativa Pusa Sugandh 2 (PS2) cultivar, a highly scented Basmati cultivar. The OsiCRY2OX transgenics displayed shorter coleoptiles and dwarfism than wild-type under blue light, white, and far-red light. Interestingly, even the dark-grown transgenics were shorter, concomitant with higher OsiCRY2 protein levels in transgenics than wild-type. Histological analysis revealed that the decrease in the length of the seedlings was due to a decrease in the length of the epidermal cells. The fully mature rice transgenics were shorter than the untransformed plants but flowered at the same time as wild-type. However, the OsiCRY2 Arabidopsis over-expressors exhibited early flowering by 10–15 days, indicating the potential and conservation of function of OsiCRY2. The whole-genome transcriptome profiling of rice transgenics revealed the differential up-regulation of several light-regulated genes in dark-grown coleoptiles. These data provide evidence that OsiCRY2 regulates photomorphogenesis, plant height, and flowering in indica rice. [ABSTRACT FROM AUTHOR]

Betulaceae species are anemophilous, and allergens from their pollen are a major cause of respiratory allergies in temperate areas where they are widely distributed. It is expected that, due to the strong influence of temperature on Betulaceae phenology, global warming will impact both the distribution and phenology of these species during the coming decades. This study examines potential decoupling of flowering and leafing phenophases in Betulaceae species (i.e. Alnus glutinosa, Betula pendula and Corylus avellana) over long-term (1951–2015) and as shorter (15-year) periods. Phenological phases for flowering and leaf unfolding of Betulaceae species from the Pan-European Phenology (PEP725) database were examined along with maximum and minimum daily temperature data for the periods September–October-November (SON), December-January–February (DJF) and March–April-May (MAM). Significant increases in temperature since 1951 have been recorded in the relevant chilling and forcing periods. Both flowering and leaf unfolding phenophases are advancing, but flowering is advancing faster than leaf unfolding. This is increasing the time between phenophases, although analysis of 15-year periods shows that the pattern of change was not constant. The results presented here represent the most comprehensive analysis of flowering and leaf unfolding phenophases of Betulaceae species using the PEP725 database to date. It is expected that these changes to Betulaceae phenology will continue and that global warming–related phenological decoupling will increase plant stress in Betulaceae populations in central Europe. [ABSTRACT FROM AUTHOR]

De novo genes created in the plant mitochondrial genome have frequently been transferred into the nuclear genome via intergenomic gene transfer events. Therefore, plant mitochondria might be a source of de novo genes in the nuclear genome. However, the functions of de novo genes originating from mitochondria and the evolutionary fate remain unclear. Here, we revealed that an Arabidopsis thaliana specific small coding gene derived from the mitochondrial genome regulates floral transition. We previously identified 49 candidate de novo genes that induce abnormal morphological changes on overexpression. We focused on a candidate gene derived from the mitochondrial genome (sORF2146) that encodes 66 amino acids. Comparative genomic analyses indicated that the mitochondrial sORF2146 emerged in the Brassica lineage as a de novo gene. The nuclear sORF2146 emerged following an intergenomic gene transfer event in the A. thaliana after the divergence between Arabidopsis and Capsella. Although the nuclear and mitochondrial sORF2146 sequences are the same in A. thaliana, only the nuclear sORF2146 is transcribed. The nuclear sORF2146 product is localized in mitochondria, which may be associated with the pseudogenization of the mitochondrial sORF2146. To functionally characterize the nuclear sORF2146, we performed a transcriptomic analysis of transgenic plants overexpressing the nuclear sORF2146. Flowering transition-related genes were highly regulated in the transgenic plants. Subsequent phenotypic analyses demonstrated that the overexpression and knockdown of sORF2146 in transgenic plants resulted in delayed and early flowering, respectively. These findings suggest that a lineage-specific de novo gene derived from mitochondria has an important regulatory effect on floral transition. Key message: A large-scale intergenomic gene transfer event involving the nuclear and mitochondrial genomes in the Arabidopsis thaliana lineage created a small coding gene that regulates floral timing. [ABSTRACT FROM AUTHOR]

Main conclusion: Heterologous expression of BnNF-YB2, BnNF-YB3, BnNF-YB4, BnNF-YB5, or BnNF-YB6 from rapeseed promotes the floral process and also affects root development in Arabidopsis. The transcriptional regulator NUCLEAR FACTOR-Y (NF-Y) is a heterotrimeric complex composed of NF-YA, NF-YB, and NF-YC proteins and is ubiquitous in yeast, animal, and plant systems. In this study, we found that five NF-YB proteins from rapeseed (Brassica napus), including BnNF-YB2, BnNF-YB3, BnNF-YB4, BnNF-YB5, and BnNF-YB6 (BnNF-YB2/3/4/5/6), all function in photoperiodic flowering and root elongation. Sequence alignment and phylogenetic analysis showed that BnNF-YB2/3 and BnNF-YB4/5/6 were clustered with Arabidopsis AtNF-YB2 and AtNF-YB3, respectively, implying that these NF-YBs are evolutionarily and functionally conserved. In support of this hypothesis, the heterologous expression of individual BnNF-YB2, 3, 4, 5, or 6 in Arabidopsis promoted early flowering under a long-day photoperiod. Further analysis suggested that BnNF-YB 2/3/4/5/6 elevated the expression of key downstream flowering time genes including CO, FT, LFY and SOC1. Promoter-GUS fusion analysis showed that the five BnNF-YBs were expressed in a variety of tissues at various developmental stages and GFP fusion analysis revealed that all BnNF-YBs were localized to the nucleus. In addition, we demonstrated that the heterologous expression of individual BnNF-YB2/3/4/5/6 in Arabidopsis promoted root elongation and increased the number of root tips formed under both normal and treatment with simulators of abiotic stress conditions. [ABSTRACT FROM AUTHOR]

Seedlings recruitment is key to maintaining populations and depends on diverse biotic interactions and abiotic factors before and after seed dispersal. Cacti recruitment is infrequent and occurs at sporadic pulses associated with rainy years. Furthermore, biotic interactions can limit seeds availability due to scarce or inefficient pollinators, dispersers or to antagonistic interactions with florivores and seed predators, as cactus depend on animals for pollination and dispersal. We identified interactions and traits involved in the regeneration process of Lophophora diffusa, during seven years (2015–21). We assessed floral rewards, pollination rates, intensity of florivory, and seed removal, to estimate the probability of recruitment through seeds, as well as survival and establishment of seedlings in a population located in Queretaro, Mexico. We found that pre-dispersal events reduced recruitment as flower–fruit transition has a low probability. High florivory and low pollinator visitation rate due to low nectar availability decreased seed formation in all years. Seed predation was not limiting recruitment, since most seeds escaped predation. Even so, a low proportion of seeds established as seedlings, possibly due to water limitation or seed dormancy. The interactions with pollinators and florivores decreased ovule–seed transition; once the seeds are formed, there is a high probability of evade predation. Hence, pre-dispersal interactions during flowering determine the availability of seeds, and reduce recruitment in peyote, rather than post-dispersal interactions. [ABSTRACT FROM AUTHOR]

'Garlic' (Allium sativum L.) is the second most important cultivated Allium known throughout the world. It is known for its versatile use as a spice, condiment, vegetable and an intended medicinal panacea. Its clove contains sulphur-based compound 'Alliin' (S-allyl-L-cysteine sulfoxide) predominantly as an active ingredient, which on physical injury to the clove becomes 'Allicin'. Alliin and allicin both are devoid of lachrymatory factor so, it does not make one tears-up while chopping garlic cloves. Origin, history, phylogeny, different types with classification, propagation, bulbils, flowering potential, studies with fertile clones, germplasm, improvement efforts along with the worth knowing well-researched facts about garlic are consolidated in the present paper. This review aims to convey an amalgamated overview of garlic and necessarily provides a retrospect of garlic's past to have a rear-view and helps to understand the status quo from the research standpoint further. It is an attempt to speculate garlic's research dimensions. [ABSTRACT FROM AUTHOR]

The timing of flowering (FL) and leaf unfolding (LU) determine plants' reproduction and vegetative growth. Global warming has substantially advanced FL and LU of temperate and boreal plants, but their responses to warming differ, which may influence the time interval between FL and LU (∆LU-FL), thereby impacting plant fitness and intraspecific physiological processes. Based on twigs collected from two flowering-first tree species, Populus tomentosa and Amygdalus triloba, we conducted a manipulative experiment to investigate the effects of winter chilling, spring warming and photoperiod on the ∆LU-FL. We found that photoperiod did not affect the ∆LU-FL of Amygdalus triloba, but shortened ∆LU-FL by 5.1 d of Populus tomentosa. Interestingly, spring warming and winter chilling oppositely affected the ∆LU-FL of both species. Specifically, low chilling accumulation extended the ∆LU-FL by 3.8 and 9.4 d for Populus tomentosa and Amygdalus triloba, but spring warming shortened the ∆LU-FL by 4.1 and 0.2 d °C−1. Our results indicate that climate warming will decrease or increase the ∆LU-FL depending on the warming periods, i.e., spring or winter. The shifted time interval between flowering and leaf unfolding may have ecological effects including affecting pollen transfer efficiency and alter the structure and functioning of terrestrial ecosystem. [ABSTRACT FROM AUTHOR]

Malt barley (Hordeum vulgare L.) is an important cash crop with stringent grain quality standards. Timing of the switch from vegetative to reproductive growth and timing of whole-plant senescence and nutrient remobilization are critical for cereal grain yield and quality. Understanding the genetic variation in genes associated with these developmental traits can streamline genotypic selection of superior malt barley germplasm. Here, we determined the effects of allelic variation in three genes encoding a glycine-rich RNA-binding protein (HvGR-RBP1) and two NAC transcription factors (HvNAM1 and HvNAM2) on malt barley agronomics and quality using previously developed markers for HvGR-RBP1 and HvNAM1 and a novel marker for HvNAM2. Based on a single-nucleotide polymorphism (SNP) in the first intron, the utilized marker differentiates NAM2 alleles of low-grain protein variety 'Karl' and of higher protein variety 'Lewis'. We demonstrate that the selection of favorable alleles for each gene impacts heading date, senescence timing, grain size, grain protein concentration, and malt quality. Specifically, combining 'Karl' alleles for the two NAC genes with the 'Lewis' HvGR-RBP1 allele extends grain fill duration, increases the percentage of plump kernels, decreases grain protein, and provides malt quality stability. Molecular markers for these genes are therefore highly useful tools in malt barley breeding. [ABSTRACT FROM AUTHOR]