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[Display omitted] • A new bHLH transcription factor PbbHLH164 binds to PbACS1b to enhance the PbACS1b expression. • PbbHLH164 promotes ethylene biosynthesis and pear fruit ripening. • PbRAD23C/D.1 interacts with PbbHLH164 to induce the degradation of PbbHLH164. • PbbHLH164 is higher expressed but PbRAD23C/D.1 is lower expressed in ripening fruits than in developing fruits. The phytohormone ethylene plays an important role in climacteric fruit ripening. However, the knowledge on molecular regulation of ethylene biosynthesis remains limited in pear fruit. Herein, a new basic helix-loop-helix transcription factor, PbbHLH164, was identified based on the transcriptome analysis of different developing and ripening fruits of two pear cultivars 'Sucui No. 1' and 'Cuiguan'. PbbHLH164 was more highly expressed in ripening fruit than in developing fruit and positively correlated with ethylene production in both cultivars. PbbHLH164 could directly bind to the promoter of 1-aminocyclopropane-1-carboxylate synthase , PbACS1b , to enhance the expression, leading to the increase of ethylene production and the acceleration of fruit ripening. Interestingly, PbbHLH164 physically interacted with an ubiquitin-like/ubiquitin-associated protein PbRAD23C/D.1, and the interaction of PbbHLH164 with PbRAD23C/D.1 attenuated the function of PbbHLH164 in enhancing the activity of the PbACS1b promoter. Notably, PbRAD23C/D.1 was involved in the degradation of PbbHLH164, and this degradation was inhibited by an ubiquitin proteasome inhibitor MG132. Different from PbbHLH164 , PbRAD23C/D.1 was more highly expressed in developing fruit than in ripening fruit of both cultivars. These results suggest that the increase of ethylene production during pear fruit ripening results from the up-regulated expression of PbbHLH164 and the down-regulated expression of PbRAD23C/D.1. This information provided new insights into the molecular regulation of ethylene biosynthesis during fruit ripening. [ABSTRACT FROM AUTHOR]

The hormonal variation essential for fruit set differs regarding crop species. Parthenocarpy is a key trait to reduce the climate dependency of fruit crops. Two distinct molecular mechanisms lead to a gibberellin-induced fruit setting. Transcription factors and miRNA interactions control parthenocarpy in several species. Fruit development is essential for flowering plants' reproduction and a significant food source. Climate change threatens fruit yields due to its impact on pollination and fertilization processes, especially vulnerable to extreme temperatures, insufficient light, and pollinator decline. Parthenocarpy, the development of fruit without fertilization, offers a solution, ensuring yield stability in adverse conditions and enhancing fruit quality. Parthenocarpic fruits not only secure agricultural production but also exhibit improved texture, appearance, and shelf life, making them desirable for food processing and other applications. Recent research unveils the molecular mechanisms behind parthenocarpy, implicating transcription factors (TFs), noncoding RNAs, and phytohormones such as auxin, gibberellin (GA), and cytokinin (CK). Here we review recent findings, construct regulatory models, and identify areas for further research. [ABSTRACT FROM AUTHOR]

• Melatonin is a multifunctional, low molecular weight signaling molecule. • Melatonin involved in key physiological processes under stress conditions. • Melatonin interacts with macro and micronutrients in plants. • Melatonin and nutrients are upcoming candidate under abiotic stresses. Plants are subjected to constant environmental changes, which lead to deleterious mineral deficiencies resulting in constraints in plant growth, and thereby limiting productivity. Essential elements are vital for the production of optimum biomass and yield, while some surplus elements are beneficial for their survival under stress and/or improvement in the quality of economic productivity. Melatonin (N-acetyl-5-methoxytryptamine), a low molecular weight signaling molecule, earlier considered as animal hormone, is now known to be synthesized and taken actions in plants. Its impact on plants ranging from dormancy, root and shoot growth, leaf senescence, osmoregulation, and flower and fruit development has been reported. Melatonin has recently gained considerable importance as a mitigator of various abiotic stressors and a multitude of studies has depicted its role in enhancing the nutritional status of crops. Subsequently, it navigates through the multifaceted relationship of melatonin with macronutrients as well as micronutrients. Melatonin modulates nutrient acquisition, assimilation, and distribution within plants, ultimately influences aspects like plant growth and crop yield. This review is a comprehensive approach to understand the role of melatonin biosynthesis, physiological responses, and melatonin interaction with different types of macronutrients and micronutrients under stressed conditions in detail, and its future scopes using genome editing tools in plants to make them more tolerant for the same. It also provides a thorough exploration of the intricate interplay between melatonin and essential macronutrients and micronutrients within the context of plant physiology. [ABSTRACT FROM AUTHOR]

• In this study, the FLOWERING LOCUS T (FT) gene, which has critical roles in flowering time, plant architecture, fruit, and seed development, was cloned and structurally characterized for the first time in apricot. • Bioinformatic characterization analyses demonstrated that PaFT is evolutionarily conserved across different species. • Expression analysis by RT-qPCR showed that PaFT may have a role in 12 different developmental stages of apricot. Flowering is an important life stage that directly affects plant growth and development. For plants, the correct timing of flowering is the basis not only for their life cycle, but also for the fruit and seed production of economically important species. FLOWERING LOCUS T (FT), which belongs to the phosphatidylethanolamine binding protein (PEBP) family, controls flowering time by encoding a small protein called florigen. In this study, FLOWERING LOCUS T gene in apricot was cloned and characterized structurally for the first-time using RT-PCR and RACE-PCR methods. Bioinformatic analysis revealed that PaFT showed very high similarity with Arabidopsis, rice, and other Rosaceae FT members at the DNA, mRNA, and protein structure levels. Phylogenetic tree analysis showed that PaFT was in the FT-clade together with FT homologues from other Prunus species. The cis-acting element analysis showed that the promoter of the PaFT gene mainly contains the elements involved in growth and development and hormone response. Moreover, gene expression analysis showed that PaFT expressed in 12 different developmental stages of leaf, flower and fruit in apricot. The findings of this study would be key to elucidating the molecular mechanism of flowering time in apricot and for molecular breeding studies aimed at obtaining late flowering phenotypes. [ABSTRACT FROM AUTHOR]

Manipulating the crop load in peach trees determines carbon supply and optimum balance between fruit yield and quality potentials. The impact of carbon supply on peach fruit quality was assessed in three development stages (S2, S3, S4) on fruit of equal maturity from trees that were carbon (C) starved (unthinned) and sufficient (thinned). Previous studies determined that primary metabolites of peach fruit mesocarp are mainly linked with developmental processes, thus, the secondary metabolite profile was assessed using non-targeted liquid chromatography mass-spectrometry (LC-MS). Carbon sufficient (C-sufficient) fruit demonstrated superior quality attributes as compared to C-starved fruit. Early metabolic shifts in the secondary metabolome appear to prime quality at harvest. Enhanced C-availability facilitated the increased and consistent synthesis of flavonoids, like catechin, epicatechin and eriodyctiol, via the phenylpropanoid pathway, providing a link between the metabolome and fruit quality, and serving as signatures of C-sufficiency during peach fruit development. [Display omitted] • Optimized crop loads enhance C-supply priming peach fruit metabolism and quality. • Primary metabolism is mainly linked with peach fruit developmental processes. • Non-targeted LC-MS revealed that flavonoids up-accumulate in the C-sufficient fruit. • Phenylpropanoids are signatures of C-sufficiency during peach fruit development. • Phenylpropanoids link primary/secondary metabolism with superior fruit quality. [ABSTRACT FROM AUTHOR]

Sugar content is one of the determining factors for melon fruit maturity. Studies have shown that starch gradually degrades during fruit ripening, resulting in sugar accumulation. But the specific relationship between starch metabolism and sucrose accumulation was still unknown. Here, the starch and sugar contents, the activities of key enzymes and the expression patterns of genes related to starch-sucrose metabolism were determined in the fruit of high sugar and starch variety 'HS' and low sugar and starch variety 'LW'. It was found that starch accumulated during fruit development process, and then degraded at 30 days after anthesis (DAA), which was synchronized with sucrose accumulation in 'HS' fruit, while starch and sucrose contents were always at a lower level during 'LW' fruit maturation. Furthermore, starch metabolism-related enzymes (Adenine dinucleotide phosphate -glucose pyrophosphorylase (AGPase), α-amylase (AMY), β-amylase (BMY)) and the key enzymes for sucrose accumulation (sucrose phosphate synthase (SPS) and sucrose synthase (SS)) were significantly increased at ripening stage of 'HS' fruit, and their activities were consistent with the expressions of CmAPS2-2 , CmAMY2 , CmBAM1 , CmBAM9 and CmSPS1. However, the contents of starch and sucrose and the activities of AGPase and SPS in 'LW' fruit didn't change significantly. We discovered an R2R3-type MYB transcription factor, CmMYB44, screened from yeast one hybrid library, could directly bind to the promoter of CmAPS2-2 to inhibit its transcription. These results revealed that the targeted down-regulation of CmAPS2-2 by CmMYB44 might be involved in the starch accumulation process, which affect the flavor quality of oriental melon fruit. • Starch degradation was synchronized with sucrose accumulation in melon fruit. • The activity of AGPase and expression of its coding gene CmAPS2-2 were consistent with the starch accumulation. • The targeted down-regulation of CmAPS2-2 by CmMYB44 might be involved in the starch accumulation process. [ABSTRACT FROM AUTHOR]

The non-climacteric octoploid strawberry (Fragaria × ananassa Duchesne ex Rozier) was used as a model to study its regulation during fruit ripening. High performance liquid chromatography electrospray tandem-mass spectrometry (HPLC-ESI-MS/MS) was employed to profile 28 different endogenous phytohormones in strawberry. These include auxins, cytokinins (CKs), abscisic acid (ABA), ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC), jasmonates, and phenolic compounds salicylic acid (SA), benzoic acid (BzA) and phenylacetic acid (PAA) together with their various metabolic forms that have remained largely unexplored thus far. ABA, ACC and CK N 6-(Δ2-isopentenyl)adenine (iP) were found to be associated with ripening while ABA catabolites 9-hydroxy-ABA and phaseic acid mimicked the pattern of climacteric decline at the turning phase of strawberry ripening. The content of other CK forms except iP decreased as fruit ripened, as also that of auxins indole-3-acetic acid (IAA) and oxo-IAA, and of jasmonates. Data presented here also suggest that both the transition and progression of strawberry fruit ripening are associated with N 6 -(Δ2-isopentenyl)adenosine-5′-monophosphate (iPRMP) → N 6 -(Δ2-isopentenyl)adenosine (iPR) → iP as the preferred CK metabolic pathway. In contrast, the ethylene precursor ACC was present at higher levels, with its abundance increasing from the onset of ripening to the red ripe stage. Further investigation of ripening-specific ACC accumulation revealed the presence of a large ACC synthase (ACS) encoding gene family in octoploid strawberry that was previously unknown. Seventeen ACS genes were found differentially expressed in fruit tissues, while six of them showed induced expression during strawberry fruit ripening. These data suggest a possible role(s) of ACC, ABA, and iP in strawberry fruit ripening. These data add new dimension to the existing knowledge of the interplay of different endogenous phytohormones in octoploid strawberry, paving the way for further investigation of their individual role(s) in fruit ripening. • Abundance of 28 endogenous phytohormones in six fruit stages of octoploid strawberry is presented. • Abscisic acid (ABA), 1-aminocyclopropane-1-carboxylic acid (ACC) and N 6-(Δ2-isopentenyl)adenine (iP) are positively associated with strawberry fruit ripening. • Cytokinin N 6 -(Δ2-isopentenyl) adenosine-5′-monophosphate (iPRMP).→ N 6 -(Δ2-isopentenyl) adenosine (iPR) → iP are identified and found associated with strawberry fruit ripening.. • Genome wide identification of 32 bonafide ACC synthase (ACS) genes were found associated with octoploid strawberry. • Expression of six ACS genes during strawberry fruit ripening corroborates with higher accumulation of ACC. [ABSTRACT FROM AUTHOR]

Jujube (Ziziphus jujuba Mill.) is a traditional fruit tree in China with immense economic and ecological value. Jujube fruits are abundant in polyphenolic secondary metabolites, particularly proanthocyanidins (PAs), which play a crucial role in enhancing the quality of jujube fruits. However, the mechanism underlying the biosynthesis of PAs remains unclear. The PA contents of sour jujube 'Qingjiansuanzao' and cultivated jujube 'Junzao' were compared at different developmental stages to unravel this mechanism. The PA contents of sour jujube were higher than that of cultivated jujube and decreased during fruit development. Combined with transcriptome analysis, a large number of differentially expressed genes related to PA biosynthesis were screened. Correlation analysis showed that ZjLAR and ZjANR played an active role in promoting the biosynthesis of PAs. Transient overexpression of ZjLAR and ZjANR in jujube fruits resulted in higher total PAs and monomeric catechin, but the PAs decreased after transient silencing. Overexpressing ZjLAR and ZjANR in Arabidopsis and tomato increased the content of PAs in Arabidopsis seeds and tomato fruits. These findings provide a new basis for further understanding of the biosynthesis of jujube PAs and are significant for improving the quality of jujube fruit. [ABSTRACT FROM AUTHOR]

Traditional methods for assessing tomato quality are time-consuming, expensive, and limited in scope. Here we developed a non-destructive spectral-based model using a handheld hyperspectral camera with 204 bands at the 400–1000 nm range, focusing on data reduction, paving the way for an economically viable device designed to assess seven key tomato quality parameters. We collected 567 fruits from five cultivars of various types and analyzed them for weight, firmness, total soluble solids (TSS), citric acid, ascorbic acid, lycopene, and pH after taking hyperspectral images of the fruits. Five commonly used spectral indices, thousands of normalized difference spectral index (NDSI) combinations, a multivariable regression model (MVR), and three machine learning (ML) algorithms (random forest – RF, extreme gradient boosting – XGBoost, and artificial neural network – ANN) were employed to predict the quality parameters from as few bands as possible. Results show that the ML models with bands selected via a hotspot overlapping method significantly improved quality prediction compared to the common spectral index approaches. Among ML algorithms, RF stood out with the best results with R2 of 0.94 for weight, 0.89 for firmness, 0.79 for lycopene, 0.72 for TSS, 0.67 for pH, 0.62 for citric acid, and 0.45 for ascorbic acid, with the only exception of ANN, which was slightly better for weight and lycopene (R2 of 0.95 and 0.85, respectively). Overall, models with only five bands were enough to predict all seven quality parameters with comparable performance to models with a larger number of bands. Our study offers an efficient and cost-effective method for assessing pre-harvest tomato quality, benefiting farmers and the food industry, as well as scientific research on fruit development and nutrition. [ABSTRACT FROM AUTHOR]

The import of nuclear-encoded preproteins into chloroplasts ensures normal organismal function. This process is recognized by the translocon at the outer membrane of chloroplast Toc GTPase dependency receptors. We identified seven Toc GTPase genes in tomato genome through bioinformatics methods, they can be divided into two subclasses (Toc34 and Toc159). The results showed that the Toc GTPase family members possessed a typical G-conserved domain and contained 0–6 introns. Expression profile analysis showed that the Toc GTPases were expressed in multiple tissues, some responsive to hormones. The yeast two-hybrid results demonstrated that nine photosynthetic proteins and 21 non-photosynthetic proteins could interact with the SlToc34-1 protein in the tomato cDNA yeast library. We found that SlToc34-1 had a higher expression level than other six Toc GTPases in tomato fruit. Transient silence expression of SIToc34-1 gene in tomato fruits resulted the fruit in a slightly lighter green color and a decreased in chlorophyll content. qRT-PCR analysis showed that silencing SIToc34-1 inhibited the expression of chloroplast synthesis genes (SlTKN2 and SlAPRR2) and photosynthetic genes (SlCBC-1 , SlRCA and SlPSBR). This observation indicated that SlToc34-1 was involved in early chloroplast development and chlorophyll reduction in tomato fruit. This work lays a foundation for further in-depth study of a complex plastid protein transport network. • Seven Toc GTPase were identified and divided into two subgroups in tomato genome. • Except for the leaves, SlToc34-1 has higher expression levels than the other six genes in all tested tomato tissues. • Toc GTPase gene showed distinct expression patterns in hormone treatments. • SlToc34-1 interacted with 21 non-photosynthetic and nine photosynthetic preproteins. • SIToc34-1 inhibited the expression of chloroplast synthesis genes (SlTKN2 and SlAPRR2) and photosynthetic genes (SlCBC-1, SlRCA and SlPSBR). [ABSTRACT FROM AUTHOR]

The cytochrome P450 (CYP) superfamily is one of the largest enzyme metabolic families found in plants thus far, playing important roles in different adaptive and biological processes including the biosynthesis of flavonoids. However, research on the CYP superfamily genes in jujube has been elusive, and the key CYP genes regulating flavonoid accumulation in jujube fruit remain unclear. A total of 154 CYP genes were identified in the jujube genome. Their conserved motifs and structures, chromosomal locations, and syntenic genes, as well as collinearities with other 5 fruit-bearing plant species, were characterized. Phylogenetic analyses placed these jujube CYP genes into 9 clans, which are further divided into 28 families, and 13 of the 28 families were categorized into A-type and 15 into non-A-type, showing a special trend compared to other species (more members in A-type). Analysis of transcriptome expression profiles and flavonoid content throughout jujube fruit development revealed nine potential genes that are associated with flavonoid production. Out of these 9 genes, only ZjCYP98A9a-89 showed an expression trend consistent with the fruit flavonoid content change during fruit development, which was validated through qPCR and was further confirmed via transient transformation in jujube fruit. During the analysis of transient overexpression, there was a notable increase in both gene expression levels and flavonoid contents. This study offers a new insight into the biological roles of CYP genes, particularly concerning flavonoid biosynthesis in jujube during fruit development. • CYP genes play crucial roles in the biosynthesis of flavonoids in jujube fruit. • A total of 154 CYP genes were identified in the jujube genome. • Flavonoid levels gradually decline during developmental stages of jujube fruit. • Expression level of ZjCYP98A9a-89 gene correlated with flavonoid content of fruits. • Reduction in flavonoid content was likely due to downregulation of ZjCYP98A9a-89. [ABSTRACT FROM AUTHOR]

• Floral and fruit phenology was studied in six Mediterranean olive cultivars. • Cultivar was the main variability source over growing season and cardinal point. • Flowering and ripening were two independent agronomic traits. • Flower buds transformed into ripe fruit were between 2.84–4.23%, fruit set 16.4–30%. • Top SPAD values were observed at full flowering and beginning of fruit development. A precise knowledge of phenological calendar and associated agroclimatic requirements of crops is of crucial importance for a better agronomical management and science. Here, six major Mediterranean olive cultivars grown in central northern Morocco were investigated for a detailed reproductive phenology calendar (according to olive BBCH specific scale), agroclimatic (chill and heat) requirements, chlorophylls (SPAD), flower bud, flower, and fruit density for two consecutive growing seasons (2021/22–2022/23). The obtained outcomes show the superiority of cultivar and growing season in explaining data variation (up to 87%) over cardinal point, which was of lesser magnitude and its contribution to the data variation did not exceed 27% (in the case of SPAD). Genotypic (cultivar) effects were dominant in determining 24 out of the 39 studied variables. Concerning cultivars, inflorescence beginning (BBCH51) was between 57.35–81.57 days of year (DOY), needing an amount of chilling of 21.47–23.46 CP and heat ranged in 198.96–344.38 GDD (growing degree-days) and 4,915.77–8,494.11 GDH (growing degree-hours). Flowering beginning (BBCH61) was between 111.29–132.66 DOY and required 538.37–764.59 GDD (12,538.3–17,884.7 GDH). BBCH71 (fruit is at 10% of its final size) timing ranged from 134.28 to 159.23 DOY, with an accumulated heat estimated between 769.94–1,033.29 GDD (18,163.4–24,281.4 GDH). Beginning of fruit Ripening (BBCH80) was reached between 256.99–279.94 DOY needing a heat amount of 2,596.4–2,897.8 GDD (59,222.2–66,382.9 GDH). The initial and full flowering sequence, from earlier to later, was 'Arbequina', 'Arbosana', 'Picholine Languedoc', 'Moroccan Picholine', 'Menara', and 'Haouzia', while that of full ripening was 'Arbequina', 'Arbosana', 'Menara', 'Moroccan Picholine', 'Picholine Languedoc', and 'Haouzia'. These results prove the independence of flowering and ripening. The 2021/22 growing season was earlier as compared to 2022/23 in terms of inflorescence, flowering, and ripening. SPAD varied according to cultivars and phenophases (top scores were observed at BBCH65–71). Flower buds (BBCH55) transformed into ripe fruit (BBCH89) ranged between 2.84 to 4.23% and fruit set varied between 16.4–30%. Dormancy release was early in tree branches facing south and east. Fruits from branches exposed to north and west displayed the highest chlorophylls content (especially for BBCH65-71) and ripened later with longer ripening duration. Principal component and cluster analysis confirmed data variation and separated cultivars, cardinal points, and growing seasons. Important correlations and regression models were highlighted among some key phenological events, agroclimatic requirements, and biomass-related traits. To conclude, genotype effects were the main driver in most of the phonological events, heat requirement, and biomass related-traits. The obtained results offer a basis for establishment and management of olive groves (OG) but also for modeling studies regarding the sustainability of OG in the framework of different scenarios of global warming. [ABSTRACT FROM AUTHOR]

• Jasmonates (JAs) are unique phytohormones ubiquitously occurring in plants. • Methyl jasmonate (MeJA) plays pivotal role in improving fruit colour and ripening. • Preharvest MeJA spray enhances colouring pigments and phytonutrients profile. • MeJA acts as an elicitor to support plant defence system against pathogens. • Preharvest MeJA sprays improve chilling injury (CI) tolerance in cold-stored fruits. Jasmonic acid (JA) and its methyl ester, methyl jasmonate (MeJA), are increasingly being recognised as unique phytohormones, linked to a variety of physiological and molecular functions. Endogenous concentrations of jasmonates (JAs) vary among plant parts, stages of fruit development, maturity, ripening and during the postharvest period. MeJA expresses prime cellular responses, where as an elicitor of secondary metabolite production, aids in inter-plant communications, regulates the biosynthesis of associated phytohormones, supports plant defence systems against pathogenic infections, and helps in abiotic stress conditions. The potential of MeJA has been extensively studied in modulating fruit ripening, enhancing colour development, and improving the phytochemical profile, particularly for antioxidants in fruit crops. Preharvest application of MeJA regulates ethylene biosynthesis during fruit maturation and ripening. Preharvest MeJA sprays have been shown to significantly increase the biosynthesis of phytochemicals such as phenolics, flavonoids, anthocyanins, carotenoids, enzymatic and non-enzymatic antioxidants, as well as essential nutrients. Preharvest MeJA application also upregulates the production of aroma volatiles in fruits. Preharvest spray of MeJA is reported to alleviate chilling injury in cold-stored fruits. This review explores: the biosynthesis of JAs, their influence on tree growth; fruit ripening physiology; colour development; regulation of biosynthesis of pigments; fruit firmness and modulation of biochemical attributes, including antioxidant compounds, during the ripening process, at harvest, and during postharvest periods; therby bridging gaps towards a more comprehensive understanding. [Display omitted] [ABSTRACT FROM AUTHOR]

• The fruit growth and development of Camellia oleifera Abel. showed an S-shaped curve. • The maximum content of squalene in the oil obtained by vacuum drying was 80.578 µg/g. • Moisture inversely affects key fatty acids. Camellia oleifera Abel. is a unique and important edible oil crop in China. The quality and high yield of C. oleifera are closely related to cultivation, management and back-end processing and storage. However, studies on the growth and development, drying treatment and back-end storage of C. oleifera are not comprehensive enough. Therefore, the phenotypic characteristics of C.oleifera fruits during growth and ripening were studied and the effects of four different drying methods including room temperature drying (SW), hot air drying (RF, 65 °C), vacuum drying (ZG, 50 °C, 0.6 Mpa) and freeze drying (LD) on the oil content of C.oleifera seeds (COS) were discussed. At the same time, the changes of the main components and nutrients of C.oleifera kernel oil (COKO) under room temperature storage (SG) and 4 °C frozen storage (LC) were also investigated. The results of the study showed that C. oleifera cultivar 'Changlin40' exhibited an S-shaped curve in fruit growth and development. In addition, the oil content initially increased and then remained stable, and the soluble protein and starch contents increased with increasing fruit maturity, but the soluble sugar content increased rapidly at the early stage of fruit development and gradually decreased at the later stage. The maximum content of squalene in the oil obtained by vacuum drying was 80.578 μg/g. The oil content of COS treated by RF was 55.31%, significantly higher than the other treatments. In addition, it was also found that with increasing duration of SG, the acid and peroxide values of COKO increased significantly and the nutrients such as tocopherol, squalene and sterol decreased significantly, which was exactly the opposite of LC, indicating that LC could reduce the loss of nutrients during storage. This study can provide a theoretical basis for field management, screening of drying methods and subsequent storage of C. oleifera. [Display omitted] [ABSTRACT FROM AUTHOR]

• γ -decalactone is the key aroma component of 'Baichang' mulberries. • Differential expression of ester synthesis genes is the formation of the unique aroma. • Transcription factors are involved in the regulation of aroma formation. Mulberries, especially the 'BaiChang' (Morus macroura) variety known for its creamy flavour, are highly valued by consumers and the market for their high nutritional value and unique aroma. However, the formation mechanism of its unique aroma compounds remains unclear. This study employed a combination of volatile metabolomics and transcriptomics analyses to examine volatile organic compounds (VOCs) and transcriptional changes at different developmental stages of 'BaiChang' mulberries. A total of 663 VOCs were identified, with 342 of annotated with different odours. Differential analysis revealed that the three comparison groups shared 56 differential metabolites, and each group contained 35, 56 and 17 unique differential metabolites. Among them, the 69 differential metabolites related to sweet, waxy, coconut and oil were screened. The content of 2(3H)-furanone, 5-hexyldihydro drastically increased during the S3 stage, and its aroma characteristics are consistent with the sensory phenotype. Among these, γ-decalactone is inferred to be the key VOC in 'BaiChang' mulberries. By integrating transcriptome data, 13 key structural genes were identified as potentially related to the synthesis of γ-decalactone, including CYPs, FAE, FAH, ACXs and EHLs. Most of these genes are highly expressed during the later stages of fruit development. Additionally, a preliminary dynamic relationship between lactones and esters was inferred during the development of 'BaiChang' mulberries. Furthermore, by combining weighted gene coexpression and K-means analyses, it was found that the biosynthesis of lactones and esters may be regulated by ethylene induction and transcription factors such as MYB, NAC, MDDS and bZIP. This study lays the foundation for understanding of the regulatory mechanisms underlying the formation of the unique aroma of 'BaiChang' mulberries and provides new insights for the further exploration of superior mulberry varieties. [ABSTRACT FROM AUTHOR]

Chinese cherry [ Cerasus pseudocerasus (Lindl.) G.Don] (syn. Prunus pseudocerasus Lindl.) is an economically important fruit crop native to China. The fruits are prone to softening and rotting after harvest, which significantly limits their marketability and hinders its rapid development throughout China. The MADS-box gene family, particularly the SEP subfamily, plays a crucial role in governing fruit ripening and softening. However, the molecular mechanisms underlying fruit ripening and softening in Chinese cherry remains unclear. Herein, we identified 92 MADS genes from the Chinese cherry genome and analyzed their physicochemical characteristics, chromosomal localization, phylogeny, gene structures, covariance, and cis-acting elements. Many cis -elements in the promoters of CpMADSs are implicated in fruit development, ripening and stress response. Using comparative transcriptomics and RT-qPCR analysis, we identified a key gene, CpMADS47 , as a positive regulator of cherry fruit ripening. CpMADS47 is localized in both the nucleus and cell membrane and shows highly expression in flowers and mature fruits. Transient overexpression of CpMADS47 in cherry fruit demonstrated its role in mediating fruit ripening and softening by promoting reduction in fruit firmness, anthocyanin accumulation, depolymerization of cell wall components, enhancement of cell wall degradation enzyme activity, and ABA biosynthesis. Conversely, silencing CpMADS47 generated the opposite effect. Yeast one-hybrid and dual-luciferase assays revealed that the CpMADS47 targets the promoters of cell wall degrading genes (CpPME3 and CpXTH31) and ABA signal transduction genes (CpPP2C12), thereby activating their transcription and promoting cherry fruit ripening. In summary, this study enriches our understanding of the transcriptional regulation of fruit ripening and softening in Chinese cherry. • A key ripening regulator, CpMADS47, was isolated from Chinese cherry. • CpMADS47 positively regulates fruit softening and ripening in Chinese cherry. • CpMADS47 activates the transcription of cell wal-degrading genes (CpPME3 and CpXTH31). • CpMADS47 mediates the ABA signal transduction pathway to promote fruit ripening. [ABSTRACT FROM AUTHOR]

Banana is a cold-sensitive fruit, which exhibits vulnerability to chilling injury (CI), causing browning, pitting, even abnormal ripening, resulting in quality deterioration and economic loss. CI development of banana fruit was caused by membrane integrity damage and was related to the enzymatic and genetic manipulation of membrane lipid metabolism pathway. The involvement of Ethylene Response Factor (ERF) transcription factors (TFs) in membrane lipid-mediated CI development of cold-sensitive fruit, such as banana, remains largely unknown. In this study, we found that cold treatment increased CI index, cell membrane permeability and MDA content, decreased hue angle (h°) value. The expressions of membrane lipids metabolism genes, including MaDGK, MaPLA, MaLipase and MaLOX, were upregulated by cold treatment. Also, two banana ERF TFs, designated as MaERF9 and MaERF113 , were induced by cold environment and displayed transactivation activities. Additionally, the electrophoretic mobility shift assay (EMSA) and transient expression analysis showed that MaERF9 and MaERF113 directly bound to the GCC-box elements in the promoters of MaDGK, MaPLA, MaLipase and MaLOX , and activated their expressions. These findings imply that MaERF9 and MaERF113 involved in CI development of banana fruit, via affecting membrane lipid metabolism. Collectively, our results provide new insights into the transcriptional regulation network regulating CI development of banana fruit. • Cold storage induces chilling injury development of postharvest banana fruit. • Cold storage increases the expressions of membrane lipids degradation-related genes. • MaERF9 and MaERF113 are transcriptional activators. • MaERF9 and MaERF113 activate the transcriptions of membrane lipids degradation-related genes via binding to their promoters. [ABSTRACT FROM AUTHOR]

Advances in the detection and mapping of DNA methylation redefine our understanding of the modifications as epigenetic regulation. In plants, the most prevalent DNA methylation plays crucial and dynamic roles in a wide variety of processes, such as stress responses, seedlings growth, fruit ripening and so on. Here, we discuss firstly the changes of DNA methylation (CG, CHG, and CHH) dynamic in plants. Second, we review the latest research progress on DNA methylation in the pigment accumulation of fruits including apple, grape, pear, kiwifruit, sweet orange, peach, cucumber, and tomato. Thirdly, the roles of DNA methylation in fruit development and ripening also are summarized. Moreover, DNA methylation is also associates with disease resistance, and flavor and nutritional quality in fruits. Lastly, we also provide some perspectives on future research of the unknown DNA methylation in fruits. [ABSTRACT FROM AUTHOR]

• The shape of mature melons can be predicted by examining the ovary shape during the early developmental stages of the pumpkin. • At the cellular level, pumpkins with different fruit shapes exhibit variations in both cell number and size within their flesh. • Key genes and transcription factors involved in the auxin and cytokinin signaling pathways interact to collectively regulate the shape of pumpkin fruit. Pumpkin (Cucurbita maxima) is a prominent cultivar in China and is highly favored by consumers. Fruit shape is a critical agronomic trait in horticultural crops, which significantly contributes to their commercial value. In this study, we compared the two inbred lines of Cucurbita maxima , 'CNG2–3–1–1′ and 'BL27–3–2–1′, which exhibited significant difference in fruit shape. We observed that 'CNG2–3–1–1′ had a notably higher fruit shape index than 'BL27–3–2–1′, potentially due to variations in gene expression regulating cell division and expansion throughout fruit development. Furthermore, fruit shape was clearly discernible in both inbred lines at the ovary stage. Transcriptome sequencing was performed at five developmental stages of the inbred lines, coupled with weighted co-expression network analysis (WGCNA), to elucidate the molecular mechanisms and interaction networks of select differentially expressed genes involved in fruit shape regulation. The findings revealed the detection of 25,653 differentially expressed genes (DEGs). In the growth hormone signaling pathway, CmaAux/IAA, CmaAUX1, CmaGH3 , and CmaSAUR , as well as CmaARR, CmaCRE1 , and CmaAHP in the cytokinin signaling pathway, exhibited differential expression between the two inbred lines. Moreover, analysis of differentially expressed transcription factors across various developmental stages suggested that CmabHLH, CmaERF, CmaWRKY, CmaHD-ZIP , and CmaMYB transcription factors may be associated with fruit expansion. It is postulated that these factors interact with target genes to collectively govern cell division and expansion in both horizontal and vertical directions, thereby influencing fruit shape difference between the two inbred lines. [ABSTRACT FROM AUTHOR]

• The application of exogenous GABA promotes fruit quality before harvest. • Exogenous GABA induces transport and anabolism of amino acids, organic acids and sugar in fruits. • GABA directly affects fruit sugar synthesis and metabolism at the transcriptomic and metabolic levels. To better explore the impact of exogenous GABA on tomato fruit quality, we explored the effects of GABA (20 mM) on tomato fruits at different developmental stages. The results showed that spraying GABA 3 days before harvest improved the quality of fruits, primarily in terms of amino acid, organic acid, and soluble sugar content. Transcriptome and metabolome data indicated that exogenous GABA enters cells and mitochondria through GABA transporters, thereby simulating endogenous GABA metabolism and enhancing the activity of genes related to amino acids and organic acids metabolism, and elevating the levels of amino acids and organic acids. Moreover, the application of exogenous GABA promoted the contents of glucose, fructose, and sucrose by affecting the expression of genes related to sugar metabolism. It was found that the mechanism of exogenous GABA in increasing fruit sugar content involved promoting sucrose synthesis, partially inhibiting glycolysis, and increasing the content of trehalose 6-phosphate. This study also provides a new model for the mechanism through which exogenous GABA affects tomato quality. [Display omitted] [ABSTRACT FROM AUTHOR]

• 'WA 38' apple fruit set and return bloom were not improved by using orchard reflective material deployed from early bloom to harvest for two seasons. • The reflective material removal after 1 month from installation at bloom negatively affected fruit retention, probably perceived as a sudden carbon deficiency. • Reflective material did not significantly influence net photosynthesis, fruit retention, yield, or fruit quality in an un-netted 'WA 38' block. • The reflective material kept in place until harvest led to a higher proportion of apples in the large size category (+20.5%) compared to control. The self-thinning nature of the apple variety 'WA 38' was previously characterized in Washington State; the self-regulating abscission of early-stage fruitlets lasts up to 8 weeks after full bloom and can result in the natural drop of 80 to 90% of the original flowers. Several approaches can be pursued to increase the fruit set, but in the present study, the focus was centered on A) alleviating the competition between young fruitlets during the early weeks of fruit development to reduce the loss by natural abscission and B) increasing the number of flower buds the following year. The study was set up in a 2018 planting of 'WA 38'/G.935 orchard without hail-nets trained to V-trellis-system (4,975 trees/ha) in Central Washington (USA). The treatment consisted of the deployment, at early king bloom, of 80% reflective white material (RM, Extenday®) in the orchard inter-rows. The hypothesis relied upon the fact that enhanced light (mainly diffuse) could increase leaf C assimilation to support and nourish a higher proportion of fruitlets and decrease the natural abscission. The RM treatments had three different durations: reflective cover removed one month after installation ("RM for 1 M"), two months after ("RM for 2 M") and until harvest ("RM until harvest"). They were compared against untreated control ("No RM (CTRL)") in a 2-year trial. RM treatments did not result in a significant positive impact on fruit retention, net photosynthetic rate, yield, or return bloom. Trees subjected to whole-season RM had altered canopy and soil microclimates with drier and warmer canopies and cooler soil with higher moisture compared to untreated control. In the second season, a greater proportion of large apples (264-339 g or 72-64 apples/40-lb-box) was graded in RM until harvest treatment, indicating a positive influence of the enhanced light treatment in C allocation to fruit. [ABSTRACT FROM AUTHOR]

• EBR and GA 3 treatment increased the contents of volatile substances, anthocyanin, and sugar to improve fruit quality. • EBR could induce GA 3 production to accelerate fruit development. • BR and GA could affect each other and had a crosstalk of that VvGAI could interact with and inhibit the VvBZR1 binding to the VvGA20ox2 promoter. Brassinosteroid (BR) and Gibberellins (GA) are important hormones that significantly influences grapeberry development and ripening. In the present study, grape clusters were soaked separately with EBR (Epi brassinolide), GA 3 , and EBR+GA 3 during fruit development. Results showed that anthocyanin content, soluble solids, and titratable acid content were all enhanced by EBR treatment, however fruit weight, transverse and longitudinal longitude, and hardness were not significantly changed, furthermore, GA 3 treatment increased the fruit weight, longitudinal and transverse longitude, and hardness, decreased titratable acid, and increased the solid acid ratio; The EBR+GA 3 significantly improved grape fruit quality, increased fruit anthocyanin content, reduced titratable acid content, improved sugar-acid ratio, and significantly improved fruit weight, transverse and longitudinal longitude, and hardness. EBR and GA 3 treatment increased the contents of alcohols, esters, ketones, terpenes, and phenols in aroma substances, and glucose and fructose. They also increased the sugar, aroma, and anthocyanin metabolism-related genes, while down-regulated the expression of acid-related genes. EBR also increased the GA metabolism associated genes, but GA 3 decereaed BR metabolism assocated genes. BR and GA had a crosstalk of that VvGAI could interact with VvBZR1, VvGAI could inhibit the VvBZR1 binding to the VvGA20ox2 promoter that decreased the VvGA20ox2 gene expression, but EBR and GA 3 could alleviate the inhibition. In conclusion, both BR and GA alone could improve fruit quality to some extent, and the combination of them can better integrate the advantages of single-use to improve the fruit quality and enhance the commerciality of the grape fruit. [ABSTRACT FROM AUTHOR]

• Simultaneous detection of multi-species mango fruits and fruiting stems. • The model exhibited exceptional performance while ensuring lightweight model. • Edge device deployment on NVIDIA Jetson Orin Nano was achieved. To prevent mango fruits from being damaged in mango fruit robotic picking, accurate and cost-effective simultaneous detection of mango fruits and fruiting stems is a key upstream task. Yet accomplishing such task remains a notable challenge due to complex and resource-limited orchard environments such as power supply, occlusion, variable light and color similarity. To address these issues, this study proposed an improved YOLOv8 model and successfully deployed it on an edge device, enabling a simultaneous detection of mango fruits and fruiting stem. Specifically, a BRA sparse attention module combined with transformer is firstly introduced into the backbone network of YOLOv8, to reduce the interference of orchard green background on mango detection. Then, the detection head of YOLOv8 was replaced via dynamic detection head combined with deformable convolution operator, to improve the detection precision for elongated mango fruiting stems. Finally, the feature fusion network of YOLOv8 is reconstructed by using GSConv-based Slimneck structure to achieve lightweight neck network, thus facilitating subsequent deployment on edge device. Experimental results showed that the improved YOLOv8 model achieved a detection precision of 97.63 % in mango fruits and a detection precision 94.5 % in fruiting stems, both surpassing lightweight state-of-the-art models including YOLOv5n, YOLOv5s, YOLOv5lite, YOLOv7tiny and YOLOV8s. Moreover, compared with the original YOLOv8n model, the improved YOLOv8 model increased the detection precision of mango fruits by 1.43 %, and the detection precision of fruiting stems by 2.8 %, while maintaining the lightweight model characteristic. To verify the effectiveness of the improved YOLOv8 model on the edge device, the proposed model was deployed on NVIDIA Jetson Orin Nano to achieve effective simultaneous detection of mango fruits and fruiting stems. This study can offer valuable technological support for automatic mango fruit robotic picking. [ABSTRACT FROM AUTHOR]

Fleshy fruit metabolism is intricately influenced by environmental changes, yet the hormonal regulations underlying these responses remain poorly elucidated. ABA and ethylene, pivotal in stress responses across plant vegetative tissues, play crucial roles in triggering fleshy fruit ripening. Their actions are intricately governed by complex mechanisms, influencing key aspects such as nutraceutical compound accumulation, sugar content, and softening parameters. Both hormones are essential orchestrators of significant alterations in fruit development in response to stressors like drought, salt, and temperature fluctuations. These alterations encompass colour development, sugar accumulation, injury mitigation, and changes in cell-wall degradation and ripening progression. This review provides a comprehensive overview of recent research progress on the roles of ABA and ethylene in responding to drought, salt, and temperature stress, as well as the molecular mechanisms controlling ripening in environmental cues. Additionally, we propose further studies aimed at genetic manipulation of ABA and ethylene signalling, offering potential strategies to enhance fleshy fruit resilience in the face of future climate change scenarios. • ABA and ethylene responding to drought, salt, and temperature stress controlling ripening. • ABA is the central hormone governing non-climacteric fruit ripening in response to drought and salt stresses. • ABA and ethylene are pivotal in promoting drought, salt, and temperature stress responses during climacteric fruit ripening. • Genetic manipulation strategies require an understanding of how ABA and ethylene alleviate abiotic stress. [ABSTRACT FROM AUTHOR]

'Katy' and 'Kuijin' apricots are the main cultivated varieties in Shandong province. The flavor of the fruit is mainly determined by sugars and acids, with soluble sugar components serving as important nutritional elements in fruits as well as crucial indicators of fruit sweetness and flavor quality. However, little is known about the changes in soluble sugar content, especially sucrose content, and the sucrose metabolism mechanism during the entire fruit growth and development process of 'Katy' and 'Kuijin' apricots. In this study, we first detected the changes in sucrose, fructose, and glucose content at nine fruit development stages of 'Katy' and 'Kuijin' apricots, and found that the stage of rapid accumulation of sucrose and fructose was from 56 days after full bloom (DAF) to 63 DAF. Therefore, we identified the key gene PaSS1 of sucrose synthase through transcriptome data screening, and further analyzed the function of the PaSS1 gene in fruit sucrose metabolism process using virus-induced gene silencing (VIGS) technology. Silencing the PaSS1 gene reduced the breakdown activity of sucrose synthase, increasing sucrose content while decreasing glucose and fructose content, delaying fruit coloring and ripening, indicating that the PaSS1 gene may regulate the ripening of apricot fruits. This study provides a theoretical basis for further research on the molecular mechanism of the PaSS1 gene in apricot fruit ripening process. • The growth curve of 'Katy' and 'Kuijin' apricot fruits shows a "double S″ curve. • The rapid growth period of sucrose and fructose is from 56 DAF to 63 DAF. • Silencing the PaSS1 gene inhibits the breakdown of sucrose in apricot fruits, delaying fruit coloring and ripening. [ABSTRACT FROM AUTHOR]

The level of sweetness in citrus fruit is crucial for consumer appeal and market competitiveness, determined mainly by soluble sugars and organic acids. ATP-dependent 6-phosphofructokinase is central to regulating sugar metabolism, yet its role in citrus fruit ripening and postharvest storage remains underexplored. We characterized phosphofructokinase genes in citrus, identifying eight genes classified into pyrophosphate-dependent phosphofructokinase (PFP) and ATP-dependent 6-phosphofructokinase (PFK) subgroups using phylogenetic analysis, genomic architectures, and protein motifs. Comparative genomic analysis with other plants highlighted significant protein homology among CitPFKs. The motif analysis indicated conserved phosphofructokinase domains in CitPFK sequences, with upstream promoter regions containing diverse cis-regulatory elements, most notably light-responsive (LREs). The gene expression profiling throughout fruit development and ripening revealed differential patterns, with responses to gibberellic acid and salicylic acid phytohormones during postharvest indicating their roles in regulating CitPFK genes. The analysis of the transcriptome showed high expression of ATP-dependent 6-phosphofructokinase 3 (CitPFK3) during fruit development, indicating a positive role in fruit maturation. Consequently, silencing CitPFK3 through virus-induced gene silencing (VIGS) increased hexose sugar content, suggesting its function in sugar accumulation. These findings improve our understanding of PFKs in citrus, particularly CitPFK3 's pivotal role in regulating hexose sugar dynamics and their modulation by exogenous phytohormones after harvest. This study provides a foundation for optimizing soluble sugar regulation to enhance fruit quality and postharvest handling in citrus production. • Characterization of Phosphofructokinase gene family members in citrus. • CitPFK genes were responsive to GA, MT, and SA phytohormones during postharvest storage. • CitPFK3 's expression level progressively increased during fruit development. • Downregulation of CitPFK3 enhanced hexose sugar accumulation. • Suppression of the CitPFK3 gene upregulated expression and activity of the PFP gene. [ABSTRACT FROM AUTHOR]

The current scenario of water scarcity leads to a seek for new irrigation strategies that maintain agricultural productivity while reducing the pressure on freshwater resources, especially in the Mediterranean region, which has a structural deficit of water sources. In this study, the effects of irrigation with water from different origins were assessed over six consecutive years in soil salinity indicators, tree physiology and yield of mandarin trees in south east Spain. The following treatments were considered: i) freshwater from the "Tagus-Segura" water-transfer canal (TW or Control); ii) reclaimed water from a wastewater-treatment plant (RW); iii) irrigation with TW, except in stage II of fruit development when RW was used (TW c); and iv) irrigation with RW except in stage II when TW was used (RW c). Soil salinity indicators increased in all treatments with respect to Control, except for TW c in winter. However, this increase only led to reductions in net photosynthesis and stomatal conductance in the RW treatment, while gas exchange parameters of trees from TW c and RW c were not negatively affected. Tree vegetative growth was only affected in the long-term, with trees from the RW c treatment having greater canopies. Yield was increased in the TW c and RW c treatments by 23.1 % and 29.5 %, respectively; while it was reduced by 23.5 % in RW when compared to TW. Likewise, differences among treatments in fruit quality traits were also detected. Our results suggest that combining water from different sources could be a viable alternative for irrigating mandarin trees under semiarid conditions with savings of approximately 50 % of fresh water, although the sustainability of soil health should be ensured. In addition, further research is needed to adapt these strategies to other species and cultivar-rootstock combinations. • Freshwater and reclaimed water were combined to irrigate mandarin trees over six years. • Soil salinity indicators increased in all treatments with respect to the control. • Tree gas exchange was only constrained by the continuous use of reclaimed water. • Vegetative growth and yield increased in the treatments combining water sources. • Combining water from different sources is a viable option for irrigating mandarin. [ABSTRACT FROM AUTHOR]

Invertases are ubiquitous enzymes that catalyze the unalterable cleavage of sucrose into glucose and fructose, and are crucially involved in plant growth, development and stress response. In this study, a total of 17 putative invertase genes, including 3 cell wall invertases, 3 vacuolar invertases, and 11 neutral invertases were identified in apple genome. Subcellular localization of MdNINV7 and MdNINV11 indicated that both invertases were located in the cytoplasm. Comprehensive analyses of physicochemical properties, chromosomal localization, genomic characterization, and gene evolution of MdINV family were conducted. Gene duplication revealed that whole-genome or segmental duplication and random duplication might have been the major driving force for MdINVs expansion. Selection index values, ω, showed strong evidence of positive selection signatures among the INV clusters. Gene expression analysis indicated that MdNINV1/3/6/7 members are crucially involved in fruit development and sugar accumulation. Similarly, expression profiles of MdCWINV1 , MdVINV1 , and MdNINV1/2/7/11 suggested their potential roles in response to cold stress. Furthermore, overexpression of MdNINV11 in apple calli at least in part promoted the expression of MdCBF1–5 and H 2 O 2 detoxification in response to cold. Overall, our results will be useful for understanding the functions of MdINVs in the regulation of apple fruit development and cold stress response. [ABSTRACT FROM AUTHOR]

Passion fruit is a tropical fruit crop with significant agricultural, economic and ornamental values. The growth and development of passion fruit are greatly affected by climatic conditions. In plants, the basic helix-loop-helix (bHLH) gene family plays essential roles in the floral organ and fruit development, as well as stress response. However, the characteristics and functions of the bHLH genes of passion fruit remain unclear. Here, 138 passion fruit bHLH members were identified and classified into 20 subfamilies. The structural analysis illustrated that PebHLH proteins of the specific subfamily are relatively conserved. Collinearity analysis indicated that the expansion of the PebHLH gene family mainly took place by segmental duplication, and the structural diversity of duplicated genes might contribute to their functional diversity. PebHLHs, which potentially regulate different floral organ and fruit development, were further screened out, and many of these genes were differentially expressed under various stress treatments. The co-presence of different cis -regulatory elements involved in developmental regulation, hormone and stress responses in the promoter regions of PebHLHs might be closely related to their diverse regulatory roles. Overall, this study will be helpful for further functional investigation of PebHLHs and provides clues for improvement of the passion fruit breeding. [Display omitted] • A total of 138 bHLH genes belonging to 20 subfamilies were identified in passion fruit. • Expansion of the bHLH gene family is primarily driven by segmental repeat events. • PebHLHs had different expression patterns in floral organ development and fruit ripening. • Specific PebHLHs are differentially expressed and play key roles under abiotic stress. • This study will be helpful to the functional characterization of PebHLHs and the breeding and improvement of passion fruit. [ABSTRACT FROM AUTHOR]

The WD40 superfamily plays an important role in a wide range of developmental and physiological processes. It is a large gene family in eukaryotes. Unfortunately, the research on the WD40 superfamily genes in Cerasus humilis has not been reported. 198 ChWD40s were identified and analyzed in the present study, along with evolutionary relationships, gene structure, chromosome distribution, and collinearity. Then, 5 pairs of tandem duplication and 17 pairs of segmental duplication were found. Based on RNA-Seq data analysis, we screened 31 candidate genes whose expression was up-regulated during the four developmental stages of fruit peel. In addition, we also demonstrated that ChWD40–140, namely ChTTG1, located in the nucleus, cytoplasm, and cytomembrane, has transcriptional activation activity and can form homodimers. ChTTG1 is involved in anthocyanin biosynthesis through heterologous overexpression in Arabidopsis. These research results provide a reference for a comprehensive analysis of the functions of WD40 in the future. [ABSTRACT FROM AUTHOR]

L-Ascorbic acid (AsA), a strong antioxidant, serves as an enzyme cofactor and redox status marker, modulating a plethora of biological processes. As tomato commercial varieties and hybrids possess relatively low amounts of AsA, the improvement of fruit AsA represents a strategic goal for enhanced human health. Previously, we have suggested that GDP-L-Galactose phosphorylase (GGP) and L-galactose-1-phosphate phosphatase (GPP) can serve as possible targets for AsA manipulation in tomato (Solanum lycopersicon L.) fruit. To this end, we produced and evaluated T3 transgenic tomato plants carrying these two genes under the control of CaMV-35S and two fruit specific promoters, PPC2 and PG-GGPI. The transgenic lines had elevated levels of AsA, with the PG-GGP1 line containing 3-fold more AsA than WT, without affecting fruit characteristics. Following RNA-Seq analysis, 164 and 13 DEGs were up- or down-regulated, respectively, between PG-GGP1 and WT pink fruits. PG-GGP1 fruit had a distinct number of up-regulated transcripts associated with cell wall modification, ethylene biosynthesis and signaling, pollen fertility and carotenoid metabolism. The elevated AsA accumulation resulted in the up regulation of AsA associated transcripts and alternative biosynthetic pathways suggesting that the entire metabolic pathway was influenced, probably via master regulation. We show here that AsA-fortification of tomato ripe fruit via GGP1 overexpression under the action of a fruit specific promoter PG affects fruit development and ripening, reduces ethylene production, and increased the levels of sugars, and carotenoids, supporting a robust database to further explore the role of AsA induced genes for agronomically important traits, breeding programs and precision gene editing approaches. • Overexpression of GGP1 under the fruit specific promoter PG resulted in a 3-fold increase in AsA content in tomato ripe fruit. • Elevated AsA influenced tomato fruit development and ripening, reduced ethylene production, and increased the levels of sugars, and carotenoids. • Up-regulated transcripts in PG-GGP1 associated with cell wall modification, ethylene biosynthesis and signaling, pollen fertility and carotenoid metabolism. [ABSTRACT FROM AUTHOR]

Basic leucine zipper (bZIP) is one of the largest transcription factor families and involved in diverse biological processes in plants. However, information on the functions of bZIP transcription factors in litchi fruit at genomic level is limited. Here, 54 LcbZIPs were identified from litchi genome and divided into 14 subfamilies: A, B, C, D, E, F, G, H, I, K, L, M, O and S. Further analysis on the distribution and collinearity of these LcbZIPs on chromosomes was conducted. Meanwhile, gene structure, promoter sequence as well as possible protein subcellular localizations of these LcbZIPs were characterized. Further, gene expression analysis of LcbZIPs accompanied with cis-element analysis as well as molecular interaction network provided further information on potential biological roles of LcbZIPs in litchi fruit development, senescence and response to fungal infection. Our results suggested that some members from subfamily C and S (LcbZIP7 , LcbZIP21 , LcbZIP28) as well as LcbZIP1 and LcbZIP4 might be involved in the regulation of litchi fruit senescence during postharvest storage. Additionally, subfamily D of LcbZIPs, especially LcbZIP40 / 41, might play important roles in the litchi fruit response to pathogen infection. Altogether, this study is beneficial to understand the function and structure of LcbZIP gene in litchi fruit. • Fifty-four LcbZIPs were identified from litchi genome. • The roles of different LcbZIPs varied during litchi fruit ripening and senescence. • LcbZIPs from subfamily D might be involved in the litchi fruit response to pathogen infection. [ABSTRACT FROM AUTHOR]

• Flowering periodicity of the study plant species showed both continuous and strong seasonality flowering patterns. • Peak flowering month coincided with the dry season of specimen collection sites. • Most study species exhibited non-seasonal fruiting when compared with flowering phenophases. • Representations of Specimens of each study species are unbalanced. • The number of collections varied extremely in each floristic region. • The number of deposited specimens of endemic species was very low when compared with the other species. • The specimen collection gap observed for the last two decades. Herbarium specimens are being used as reliable sources for estimating phenological behavior for plant species. Flowering and fruiting periodicity of 520 herbarium specimens, collected between 1948 and 2007 and deposited at the National Herbarium of Ethiopia, were investigated. Scientific names, collection date and locality of specimens were documented to assess the periodicity of phenological events. For the evaluation of periodicity of reproductive phenophases, the presence of flowering and fruiting were visually confirmed from each specimen. Examination of flowering periodicity of Bersama abyssinic a, Brucea antidysenterica, Maytenus arbutifolia and Rosa abyssinica showed continuous flowering while Prunus africana, Lobelia rhynchopetalum, Kniphofia foliosa, Solanecio gigas, Buddleja polystachya, Dombeya torrida and Embelia schimperi exhibited seasonal flowering. Although the fruiting period is extended over several months (B. abyssinica, B. antidysenterica, E. schimperi, M. arbutifolia and R. abyssinica), seasonality in fruiting was also observed in K. foliosa, L. rhynchopetalum and P. africana. The highest number of specimens found belonged to M. arbutifolia followed by B. abyssinca and B. antidysenterica , while the highest number of specimens were collected from Shewa Upland followed by Keffa and Bale floristic regions. Surprisingly, Euryops pinifolius, a species endemic to Ethiopia, was represented by only one specimen collected from Gojjam in 1985. The results revealed that herbarium specimens can be used to study flowering and fruiting periodicity of plant species. Therefore, botanists should be encouraged to continue collecting herbarium specimens based on the distribution of species in the flora area to avoid spatial and species biases for future studies. [ABSTRACT FROM AUTHOR]

Jujube (Ziziphus jujuba Mill.) is a popular fruit with health benefits ascribed to its various metabolites. These metabolites determine the flavors and bioactivities of the fruit, as well as their desirability. However, the dynamics of the metabolite composition and the underlying gene expression that modulate the overall flavor and accumulation of active ingredients during fruit development remain largely unknown. Therefore, we conducted an integrated metabolomic and transcriptomic investigation covering various developmental stages in the jujube cultivar Z. jujuba cv. Jinsixiaozao, which is famous for its nutritional and bioactive properties. A total of 407 metabolites were detected by non-targeted metabolomics. Metabolite accumulation during different jujube developmental stages was examined. Most nucleotides and amino acids and their derivatives accumulated during development, with cAMP increasing notably during ripening. Triterpenes gradually accumulated and were maintained at high concentrations during ripening. Many flavonoids were maintained at relatively high levels in early development, but then rapidly decreased later. Transcriptomic and metabolomic analyses revealed that chalcone synthase (CHS), chalcone isomerase (CHI), flavonol synthase (FLS), and dihydroflavonol 4-reductase (DFR) were mainly responsible for regulating the accumulation of flavonoids. Therefore, the extensive downregulation of these genes was probably responsible for the decreases in flavonoid content during fruit ripening. This study provide an overview of changes of active components in 'Jinsixiaozao' during development and ripening. These findings enhance our understanding of flavor formation and will facilitate jujube breeding for improving both nutrition and function. • Transcriptome and metabolome analyses of 'Jinsixiaozao' were completed throughout development. • The content of most active compounds decreased gradually with the jujube fruit maturity. • Many flavonoids were maintained high levels in the early stage, but then rapidly decreased. • The decrease in flavonoid content was probably caused by the downregulation of CHS , CHI , and FLS. [ABSTRACT FROM AUTHOR]

• Physico-chemical characterization of 16 diverse mango genotypes at maturity and deciphering the changes in different phenolic fractions and sugars with different fruit development stage. • LC-MS identified 14 major phenolic fractions in the contrasting mango genotypes. • Gallic acid content was found to increase with the fruit development stage, while catechin content decreased with the fruit development stage. • LC-MS identified glucose, fructose & sucrose as the major fractions. At ripening stage, sucrose was predominant sugar, the other fraction declined. • Results suggest for different indented use based on fruit development stages. Physico-chemical properties of 16 diverse mango genotypes were estimated at ripe stage, besides phenolic and sugar fractions were quantified in eight contrasting genotypes during different fruit developmental stages (egg, mature and ripe). The maximum fruit weight and length (298.33 g, 11.85 cm) were observed in Mallika compared to St. Alexandrina (100.80 g, 7.73 cm). Genotype Langra (861.44 mg/ 100 g) registered the highest total phenolics content, while lowest was in Dashehari (338.73 mg/ 100 g). The genotype Mallika had the maximum total soluble sugars (9.64%), compared to Totapuri (6.43%), which was minimum. Phenolic profiling using LC-MS/MS identified 14 major phenolic fractions, namely, quinic acid, methyl gallate, gallic acid, mangiferin and other minor fractions, of which gallic acid and catechin were further quantified. The gallic acid content was observed to increase from egg stage (0.864 mg/100 g) to ripe stage (3.065 mg/ 100 g). In contrast, catechin content declined from egg stage (0.820 mg/ 100 g) to ripe stage (0.050 mg /100 g). The major sugar fractions identified through LC-MS/MS were glucose, fructose and sucrose, which were found to increase with the advancement in fruit developmental stages, though the sucrose was found highest at ripening. [ABSTRACT FROM AUTHOR]

Accurate detection of apples is a key factor in improving the efficiency of bagging robots. During the young fruiting stage, factors such as similarities between young apples and background leaves, occlusion, and small targets pose a challenge to apple detection. In this study, an apple dataset of 3590 images is constructed at the apple base in Yuncheng City, Shanxi Province. The Squeeze Excitation Block (SE Block), the Atrous Spatial Pyramid Pooling and Convolutional Block Attention Module (ASPP-CBAM), along with an additional low-level prediction head (P2) are fused in the You Only Look Once v7 (YOLOv7) for detecting young fruiting apples, named YOLOv7-SAP. Firstly, to diminish the rate of false detections caused by the color similarity between fruit and background, the SE Block is added to the backbone network of YOLOv7 to selectively emphasize the information characteristics. Secondly, to minimize the loss of information about young fruits due to occlusion, the ASPP is added in front of the SE Block to complement the extracted young apple features. Finally, to address the issue of model oversampling affecting small target detection, the P2 layer is introduced within our enhanced model structures. To mitigate discrepancies between predicted and actual frames, CIoU loss in the original network is substituted with EIoU loss. The performance of the YOLOv7-SAP model is documented with a precision (P), the recall (R), the mean average precision (mAP@.5), and the F1 score of the YOLOv7-SAP model reach 89.30%, 88.20%, 91.20%, and 88.75%, respectively. Compared with YOLOv3, YOLOv5, YOLOv7, SSD, and Faster R-CNN, the YOLOv7-SAP model significantly improved the detection of young fruiting apples. • To ensure the comprehensiveness and validity of the experiment, a new dataset of apples at the young fruiting stage is constructed in the natural environment. • This study considers the detection difficulties caused by background similarity, occlusion, and small targets in a framework. To target these factors, the SE Block, the ASPP-CBAM, and the P2 are integrated into the original YOLOv7 model, namely YOLOv7-SAP. • The YOLOv7-SAP model exhibits superior performance in detecting apples during the young fruiting stage. [ABSTRACT FROM AUTHOR]

Charantin in M. charantia fruit comprises stigmasterol glucoside (STG) and β-sitosterol glucoside (BSG). Despite numerous studies on charantin quantification and health beneficial bioactivity, thermal stability of two components remains unclear. This study investigated the thermal stability of BSG and STG in the fruit growth stages (S1–S5). Freeze-dried fruit contained approximately twice higher BSG than STG, with the content tending to decrease during fruit maturation. A dramatic decrease in content was observed between S2 and S3, with a reduction of 70 % for BSG and 75 % for STG. In thermal processing, BSG significantly degraded above 30 °C treatments, while STG remained stable. It was found that the thresholds of thermal stability were approximately 10 °C for BSG and 30 °C for STG. Therefore, minimal thermal processing or freeze-drying is recommended for preserving charantin in the fruit. • BSG is more abundant than STG throughout all stages of fruit development. • Both BSG and STG decrease as the fruit matures. • Thermal stability of charantin was up to 10 °C for BSG and 30 °C for STG. • BSG thermal degradation was severer than STG, especially in early fruit stages. • Minimal thermal processing is recommended for preserving charantin. [ABSTRACT FROM AUTHOR]

Capsaicin (CAP), a crucial compound found in chili peppers, not only contributes to their spicy flavor but also possesses several industrial applications. CAP biosynthetic pathway is well known, while its transport mechanism remains elusive. Herein, we performed a comparative transcriptome analysis conducted on pepper fruit tissues at three different stages of development. Four important CAP transporter genes, including one MATE and three ABCs , were identified by differential expression and WGCNA analysis. Specifically, the expression patterns of three ABC genes were assessed in the septum of fruits from nine distinct genotypes of peppers with high capsaicin levels. Interestingly, CaABCG14 was associated with variations in CAP concentration and co-expressed with genes involved in CAP biosynthesis. Transient expression assay revealed that CaABCG14 is localized to the membrane and nucleus. Silencing of CaABCG14 resulted in a notable reduction in the levels of CAP contents and the expression of its biosynthetic genes in the septum of pepper. The overexpression of CaABCG14 greatly intensified the cytotoxic effects of CAP on the yeast cells. Taken together, we for the first time identified a new transporter gene CaABCG14, regulating the CAP accumulation in pepper septum. These findings offer a fresh molecular theoretical framework for CAP transport and accumulation. • Capsaicin (CAP) is a major flavoring compound in pepper. • The CaABCG14 is crucial for CAP transport. • Silencing of CaABCG14 negatively affects CAP transport and accumulation. • Overexpression of CaABCG14 increased the cytotoxic effect of CAP on yeast cells. [ABSTRACT FROM AUTHOR]

UDP-glycosyltransferases (UGTs) play a crucial role in the glycosylation of secondary metabolites in plants, which is of significant importance for growth and response to biotic or abiotic stress. Despite the wide identification of UGT family members in various species, limited information is available regarding this family in citrus. In this study, we identified 87 UGT genes from the Citrus sinensis genome and classified them into 14 groups. We characterized their gene structures and motif compositions, providing insights into the molecular basis underlying discrepant functions of UGT genes within each evolutionary branch. Tandem duplication events were found to be the main driving force behind UGT gene expansion. Additionally, we identified numerous cis-acting elements in the promoter region of UGT genes, including those responsive to light, growth factors, phytohormones, and stress conditions. Notably, light-responsive elements were found with a frequency of 100 %. We elucidated the expression pattern of UGTs during fruit development in Citrus aurantium using RNA-seq and quantitative real-time PCR (qRT-PCR), revealing that 10 key UGT genes are closely associated with biosynthesis of bitter flavanone neohesperidosides (FNHs). Furthermore, we identified Ca1,2RhaT as a flavonoid 1–2 rhamnosyltransferase (1,2RhaT) involved in FNHs biosynthesis for the first time. Isolation and functional characterization of the gene Ca1,2RhaT from Citrus aurantium in vitro and in vivo indicated that Ca1,2RhaT encoded a citrus 1,2RhaT and possessed rhamnosyl transfer activities. This work provides comprehensive information on the UGT family while offering new insights into understanding molecular mechanisms regulating specific accumulation patterns of FNHs or non-bitter flavanone rutinosides (FRTs) in citrus. [ABSTRACT FROM AUTHOR]

Aromatic coconut represents an exceptional variety of coconut known for its distinct and delightful flavor and aroma, both of which are highly cherished by consumers. Despite its popularity, there has been a lack of systematic research on aroma components and the associated synthetic genes. In this report, we developed the metabolite profiles of terpenoids by targeted metabolomics and obtained the expression profile of genes related to terpenoid biosynthesis by RNA-seq during different coconut fruit developmental stages. Totally, we separated 26 different terpenoids in aromatic coconut pulp, among which, geranyl acetate and (−)-isosyngene emerged as the most abundant. The integrated analysis of metabolism and RNA-seq data showed that HMGS2 , HMGS3 , IPI/IDI1 , HMGR1 , HMGR3 , and CMK2 as potentially key genes involved in the synthesis of terpenoids in aromatic coconut. To validate these findings, qRT-PCR was conducted on terpenoid-related genes. These findings lay a foundation for understanding aroma formation and the molecular mechanism of terpenoids in coconut fruit. [ABSTRACT FROM AUTHOR]

• The first documentation of blue honeysuckle phenology is provided. • Annual growth was characterized by eight primary and 35 secondary growth stages. • Overlapping flowering times indicate cultivars can serve as mutual pollinizers. • Extent of sepal withering may serve as an indicator for assessing fruit maturity. Blue honeysuckle (Lonicera caerulea L.) is an emerging fruit crop from the temperate to circumpolar climate regions with outstanding agronomic traits, substantial nutritional value, and versatile processing applications. However, the limited understanding of its phenology poses substantial challenges to its cultivation, breeding, and research. In this study, we characterized the progressive phenological growth stages of blue honeysuckle according to the BBCH (Biologische Bundesanstalt, Bundessortenamt und Chemische Industrie) scale by investigating three major cultivars (L. caerulea) and a wild accession (L. caerulea var. edulis) in Harbin, China (hot-summer humid continental climate) during 2022–2023. The annual growth of blue honeysuckle was characterized by eight primary stages, including bud development (0), leaf development (1), shoot development (3), inflorescence emergence (5), flowering (6), fruit development (7), fruit ripening (8), and senescence and dormancy (9). Additionally, 35 secondary growth stages were documented, among which eight stages are related to fruit development and ripening. The annual growth period of blue honeysuckle spans 6.5–7 months, starting from late March and ending in early October. The flowering season lasts for 2–3 weeks, ranging from late April to mid-May. The fruit development and ripening last for 7–9 weeks, beginning in early May and ending in early July. This study provides valuable insights for the cultivation and research of blue honeysuckle. [ABSTRACT FROM AUTHOR]

• Carotenoids are responsible for the coloring of most fruits at maturity. • Plastids play a central role in the carotenoid accumulation, stability and diversity. • Plastid types are interconvertable. • Plastid transformation leads to color change during fruit maturity. Carotenoid accumulation is an important feature that not only enhances the aesthetic appeal of fruits but also contributes to nutritional value. Plastids, the specialized organelles found in plants, play a crucial role in synthesizing and storing significant amounts of carotenoids. They encompass various types, including proplastids, etioplasts, leucoplasts, chloroplasts, and chromoplasts. These plastids are pivotal in the accumulation, stability, and diversity of carotenoids. During fruit development and ripening, plastid differentiation occurs, accompanied by changes in subplastidial structures, leading to alterations in fruit coloration. In this review, we provide a overview of the diverse types of plastids, their interconversions, as well as variations in size and number, all of which contribute to the distinctive coloration exhibited by fruits. Understanding the fundamental mechanisms underlying chromoplast development and carotenoid accumulation holds great promise for enhancing our knowledge of fruit pigmentation and nutritional quality. [ABSTRACT FROM AUTHOR]

• The overexpression of Sly-miR172a improved the quality of tomato fruit. • The cell number and cell area of tomato fruit were increased in OE-miR172a fruit. • The accumulation of lycopene and soluble sugars was increased in OE-miR172a fruit. • Up-regulated AG1 and AGL1 by decreasing the expression level of SlAP2 in OE-miR172a. Fruit development is the key link in the reproductive cycle of plants, which determines the quality, yield and economic value of fruit. The present study investigated the effect of Sly-miR172a on the quality of the tomato fruit. The research results showed that overexpression of Sly-miR172a (OE-miR172a) in tomato fruit efficaciously increased the transverse and longitudinal diameter, weight, pericarp thickness, cell number and cell area. Compared with the wild-type (WT) fruit and the silencing miR172a by short tandem target mimic (STTM-miR172a), the relative expression levels of the MADS-box and the flavonoid biosynthesis synthesis pathway genes were higher in OE-miR172a. The expression level of AP2 and Cytokinin oxidase/dehydrogenase (CKX) family genes in OE-miR172a fruit was decreased, and accumulated more content of soluble sugars, lycopene, carotenoid, total phenol, anthocyanin and total flavonoid. The present study showed that overexpression of Sly-miR172 promoted the development and improved quality of tomato fruit. [ABSTRACT FROM AUTHOR]