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Summary Single‐cell RNA‐seq (scRNA‐seq) has been highlighted as a powerful tool for the description of human cell transcriptome, but the technology has not been broadly applied in plant cells. Herein, we describe the successful development of a robust protoplast cell isolation system in the peanut leaf. A total of 6,815 single cells were divided into eight cell clusters based on reported marker genes by applying scRNA‐seq. Further, a pseudo‐time analysis was used to describe the developmental trajectory and interaction network of transcription factors (TFs) of distinct cell types during leaf growth. The trajectory enabled re‐investigation of the primordium‐driven development processes of the mesophyll and epidermis. These results suggest that palisade cells likely differentiate into spongy cells, while the epidermal cells originated earlier than the primordium. Subsequently, the developed method integrated multiple technologies to efficiently validate the scRNA‐seq result in a homogenous cell population. The expression levels of several TFs were strongly correlated with epidermal ontogeny in accordance with obtained scRNA‐seq values. Additionally, peanut AHL23 (AT‐HOOK MOTIF NUCLEAR LOCALIZED PROTEIN 23), which is localized in nucleus, promoted leaf growth when ectopically expressed in Arabidopsis by modulating the phytohormone pathway. Together, our study displays that application of scRNA‐seq can provide new hypotheses regarding cell differentiation in the leaf blade of Arachis hypogaea. We believe that this approach will enable significant advances in the functional study of leaf blade cells in the allotetraploid peanut and other plant species.

Plant leaves display considerable variation in shape. Here, we introduce key aspects of leaf development, focusing on the morphogenetic basis of leaf shape diversity. We discuss the importance of the genetic control of the amount, duration, and direction of cellular growth for the emergence of leaf form. We highlight how the combined use of live imaging and computational frameworks can help conceptualize how regulated cellular growth is translated into different leaf shapes. In particular, we focus on the morphogenetic differences between simple and complex leaves and how carnivorous plants form three-dimensional insect traps. We discuss how evolution has shaped leaf diversity in the case of complex leaves, by tinkering with organ-wide growth and local growth repression, and in carnivorous plants, by modifying the relative growth of the lower and upper sides of the leaf primordium to create insect-digesting traps.

The production of passion fruit in commercial areas requires a good correction of nutrients in the soil, however, with nutritional restrictions it can cause symptoms of deficiency expressed mainly in the leaves and stems, which may appear spots, reduced growth, changes in the architecture of these organs mainly in the its size and shape. This work aimed to know the effects caused by the suppression of nutrients in passion fruit species with an approach on their development and leaf morphology. The experimental design was completely randomized (DIC) in a 2x6 factorial scheme where the first factor was composed of two passion fruit species: P. gibertiiand P. edulis, interacting with the availability of nutrients, that is, a control group with the supply of all nutrients, with nitrogen suppression (N); phosphorus (P); potassium (K); magnesium (Mg) and iron (Fe), totaling 12 treatments with four replications totaling 48 plots or plastic vessels per experiment. The species P. edulisshowed better responses to the variables of development andleaf morphology. The species P. gibertiiis more susceptible to nutrient deficiency and showed changes in the color and shape of its leaves with the restriction of nutrients. The nutrients Fe and Mg caused greater restrictions on the development and leaf morphology of passion fruit species. It is necessary to carry out a new study with the species P. gibertiiregarding the appropriate concentrations of N, P and K provided in planting and cover, as this species is used as a rootstock in commercial areas

Substantial diversity exists for both the size and shape of the leaf, the main photosynthetic organ of flowering plants. The two major forms of leaf are simple leaves, in which the leaf blade is undivided, and compound leaves, which comprise several leaflets. Leaves form at the shoot apical meristem from a group of undifferentiated cells, which first establish polarity, then grow and differentiate. Each of these processes is controlled by a combination of transcriptional regulators, microRNAs and phytohormones. The present review documents recent advances in our understanding of how these various factors modulate the development of both simple leaves (focusing mainly on the model plant Arabidopsis thaliana) and compound leaves (focusing mainly on the model legume species Medicago truncatula).

Faba bean (Vicia faba L.) is an important traditional pulse crop in many parts of Asia and the Mediterranean region. However, water deficit and temperature, two of the key variables associated with...

The world-wide distribution ofArabidopsis thaliana(Arabidopsis) accessions imposes different types of evolutionary pressures, which contributes to various responses of these accessions to environmental stresses. Drought stress responses have been well studied, particularly in Columbia, a common Arabidopsis accession. However, the reactions to drought stress are complex and our understanding of which of these responses contribute to the plant’s tolerance to mild drought is very limited. Here, we studied the mechanisms by which natural accessions react to mild drought at a physiological and molecular level during early leaf development. We documented variations in mild drought tolerance among natural accessions and used transcriptome sequencing of a drought-sensitive accession, ICE163, and a drought-tolerant accession, Yeg-1, to get insights into the mechanisms underlying this tolerance. This revealed that ICE163 preferentially induces jasmonates and anthocyanin-related pathways, which are beneficial in biotic stress defense, while Yeg-1 has a more pronounced activation of abscisic acid signaling, the classical abiotic stress response. Related physiological traits, including content of proline, anthocyanins and ROS, stomatal closure and cellular leaf parameters, were investigated and linked to the transcriptional responses. We conclude that most of these processes constitute general drought response mechanisms that are regulated similarly in drought-tolerant and -sensitive accessions. However, the capacity to close stomata and maintain cell expansion under mild drought appeared to be major factors that contribute to a better leaf growth under mild drought.One-sentence summaryThis paper demonstrates that an efficient closure of stomata and maintenance of cell expansion during drought conditions are crucial to maximally preserve plant growth during water deficit.

The essential oil of Cinnamomum burmannii (Nees and T. Nees) Blume is rich in monoterpenes and sesquiterpenes. The post-transcriptional regulatory mechanisms controlling the expression of terpenoid-related genes have not yet been clarified in C. burmannii. Here, we conducted a metabolomic analysis of the leaves of C. burmannii across four developmental stages using gas chromatography–mass spectrometry. We also identified miRNAs and their target genes involved in terpenoid biosynthesis using small RNA sequencing. A total of 135 differentially expressed metabolites were detected, including 65 terpenoids, 15 aldehydes, and 13 benzenes. A total of 876 miRNAs from 148 families were detected, among which 434 miRNAs were differentially expressed, including three known miRNAs and 431 novel miRNAs. Four miRNAs (gma-miR5368, novel_miR_377, novel_miR_111, and novel_miR_251) were predicted to regulate the expression of four differential expressed genes involved in the monoterpenoid and sesquiterpenoid synthesis. miRNAs families miR396, miR5185, and miR9408 were predicted to play diverse regulatory roles in monoterpenoid and sesquiterpenoid synthesis during the leaf development of C. burmannii. The results of our study shed new light on the roles of regulatory genes in terpenoid biosynthesis. Our findings also have implications for the further promotion of essential oil production using the leaves of C. burmannii.

Premise of research. MYB transcription factors are one of the largest families of genes in land plants. They are involved in many regulatory processes, such as primary and secondary metabolism, cel...

The LAM1 transcription factor regulates expansion of primary leaflets in the compound leaves of tomato, and also affects floral organ development, fruit size, and initiation of secondary leaflets., Plant-specific WOX family transcription factors play important roles ranging from embryogenesis to lateral organ development. The WOX1 transcription factors, which belong to the modern clade of the WOX family, are known to regulate outgrowth of the leaf blade specifically in the mediolateral axis; however, the role of WOX1 in compound leaf development remains unknown. Phylogenetic analysis of the whole WOX family in tomato (Solanum lycopersicum) indicates that there are 10 members that represent the modern, intermediate, and ancient clades. Using phylogenetic analysis and a reverse genetic approach, in this study we identified SlLAM1 in the modern clade and examined its function and tissue-specific expression pattern. We found that knocking out SlLAM1 via CRISPR/Cas9-mediated genome editing led to narrow leaves and a reduced number of secondary leaflets. Overexpression of tomato SlLAM1 could rescue the defects of the tobacco lam1 mutant. Anatomical and transcriptomic analyses demonstrated that floral organ development, fruit size, secondary leaflet initiation, and leaf complexity were altered due to loss-of-function of SlLAM1. These findings demonstrate that tomato SlLAM1 plays an important role in the regulation of secondary leaflet initiation, in addition to its conserved function in blade expansion.

International audience; Leaf optical properties impact leaf energy balance and thus leaf temperature. The effect of leaf development on mid-infrared (MIR) reflectance, and hence thermal emissivity, has not been investigated in detail. We measured a suite of morphological characteristics, as well as directional-hemispherical reflectance from ultraviolet to thermal infrared wavelengths (250 nm to 20 µm) of leaves from five temperate deciduous tree species over the 8 wk following spring leaf emergence. By contrast to reflectance at shorter wavelengths, the shape and magnitude of MIR reflectance spectra changed markedly with development. MIR spectral differences among species became more pronounced and unique as leaves matured. Comparison of reflectance spectra of intact vs dried and ground leaves points to cuticular developmentand not internal structural or biochemical changesas the main driving factor. Accompanying the observed spectral changes was a drop in thermal emissivity from about 0.99 to 0.95 over the 8 wk following leaf emergence. Emissivity changes were not large enough to substantially influence leaf temperature, but they could potentially lead to a bias in radiometrically measured temperatures of up to 3 K. Our results also pointed to the potential for using MIR spectroscopy to better understand species-level differences in cuticular development and composition.

Both the evolution of tree taxa and whole-genome duplication (WGD) have occurred many times during angiosperm evolution. Transcription factors are preferentially retained following WGD suggesting that functional divergence of duplicates could contribute to traits distinctive to the tree growth habit. We used gain- and loss-of-function transgenics, photoperiod treatments, and circannual expression studies in adult trees to study the diversification of three Populus FLOWERING LOCUS D-LIKE (FDL) genes encoding bZIP transcription factors. Expression patterns and transgenic studies indicate that FDL2.2 promotes flowering and that FDL1 and FDL3 function in different vegetative phenophases. Study of dominant repressor FDL versions indicates that the FDL proteins are partially equivalent in their ability to alter shoot growth. Like its paralogs, FDL3 overexpression delays short day-induced growth cessation, but also induces distinct heterochronic shifts in shoot development—more rapid phytomer initiation and coordinated delay in both leaf expansion and the transition to secondary growth in long days, but not in short days. Our results indicate that both regulatory and protein coding sequence variation contributed to diversification of FDL paralogs that has led to a degree of specialization in multiple developmental processes important for trees and their local adaptation.

The rachis of most growing compound leaves observed in nature exhibits a stereotypical hook shape. In this study, we focus on the canonical case of Averrhoa carambola. Combining kinematics and mechanical investigation, we characterize this hook shape and shed light on its establishment and maintenance. We show quantitatively that the hook shape is a conserved bent zone propagating at constant velocity and constant distance from the apex throughout development. A simple mechanical test reveals non-zero intrinsic curvature profiles for the rachis during its growth, indicating that the hook shape is actively regulated. We show a robust spatial organization of growth, curvature, rigidity, and lignification, and their interplay. Regulatory processes appear to be specifically localized: in particular, differential growth occurs where the elongation rate drops. Finally, impairing the graviception of the leaf on a clinostat led to reduced hook curvature but not to its loss. Altogether, our results suggest a role for proprioception in the regulation of the leaf hook shape, likely mediated via mechanical strain.

Au Niger Est, la faible disponibilité sur les marchés ruraux, la cherté et le faible pouvoir d’achat des paysans limitent l’application des engrais minéraux. L’objectif de cette étude est l’évaluation de l’effet du guano sur la production de la laitue. Le dispositif expérimental est un bloc complet randomisé avec dix-sept traitements issus de la combinaison entre 4 doses de guano, 2 doses de fumier et 2 doses d’engrais en trois (3) répétitions. Les paramètres étudiés portent sur les diamètres de pomme, la hauteur des parties aériennes, le développement foliaire et le rendement. Les résultats obtenus révèlent que le guano a un effet significatif sur la production de laitue. A la dose optimale 3,5 t/ha, le guano a permis d’augmenter la production de la laitue de 833 et 628% par rapport au témoin et aux parcelles ayant reçues uniquement la fumure minérale. La combinaison guano et fumure organique a permis d’accroitre le rendement par rapport aux parcelles fertilisées avec le guano seulement, tandis que l’apport de l’engrais minéral a un effet dépressif sur le rendement. Pour assurer une bonne production de laitue dans la cuvette de Balla, il serait préférable d’utiliser la combinaison guano (3,5 t/ha) avec du fumier. La préservation de la population de chauves-souris permettrait d’assurer la durabilité de la filière guano.Mots clés : Fertilisation, guano, laitue, cuvette oasienne, Gouré. English Title: Guano, a natural organic fertilizer alternative to manure, tested on the production of green lettuce (lactuca sativa L.) in oasis of Balla (department of Gouré), Zinder, Niger In eastern Niger, low availability in local markets, high prices and low purchasing power of farmers limit the application of mineral fertilizers. The objective of this study is to evaluate the effect of guano on lettuce production. The experimental design is a randomized complete block with seventeen treatments resulting from the combination of four doses of guano, two doses of manure and two doses of fertilizer in three (3) replicates. The parameters studied for this experiment are: diameter of head, cabbage height of aerial parts, leaf development and yield. The results show that guano had a significant effect on lettuce production. At the optimum rate of 3,5 t/ha, guano increased lettuce production by 833 and 628% compared with the control and the plots receiving only the mineral fertilizer respectively. The combination of guano and organic fertilizer increased the yield compared to the plots fertilized with guano only, while the mineral fertilizer input had a depressive effect on yield. To ensure a good lettuce production in the Balla lowland, it would be better to use the guano combination (3,5 t/ha) with manure. Preserving the bat population would help ensure the sustainability of the guano industry.Keywords: Fertilizer, guano, lettuce, Oasis bassin, Gouré.

The 'canalization hypothesis' was suggested 50 years ago by Tsvi Sachs to account for the formation of vascular strands in response to wounding or auxin application. The hypothesis proposes that positive feedback between auxin movement through a cell and the cell's auxin conductivity leads to the gradual selection of narrow 'canals' of polar auxin transport that will differentiate into vascular strands. Though the hypothesis has provided an invaluable conceptual framework to understand the patterned formation of vascular strands, evidence has been accumulating that seems to be incompatible with the hypothesis. We suggest that the challenging evidence is incompatible with current interpretations of the hypothesis but not with the concept at the core of the hypothesis' original formulation.

Bud and leaf development are important phenological events and help in defining the growing period of trees. Canopy greenness derived from PhenoCam has been used to investigate leaf phenology. Ques...

Allopolyploidy is long recognized as an essential driving force in plant evolution. Recent studies have demonstrated that small RNAs, including microRNAs (miRNAs), play important roles in the process of allopolyploidy. However, the question that how the distinct parent-of-origin miRNAs are maintained in allopolyploids and how these small RNAs affect gene expression and phenotype remain to be answered. Therefore, we investigated the miRNA expression profiles of a synthesized allotetraploid, Cucumis xhytivus and its parents. The different developmental stages of leaves of C. xhytivus showing contrasting leaf colour were compared as well. Following high-throughput sequencing. 546 conserved d 287 novel miRNAs were identified. The expressions of nine miRNAs obtained by real-time quantitative PCR were consistent with the sequencing results. We detected that 15 miRNAs were divergently expressed between the parent species, and 23 miRNAs were differentially expressed in C. xbytivus compared to either of its parents or both, which suggests the significant effect of allopolyploidization on miRNAs accumulation. Additionally, 26 conserved and 13 novel miRNAs differed in expression between the young and mature leaves of C. xhytivus, indicating an essential role of miRNA-mediated regulation of leaf development following allopolyploidization. This study enriches the context of allopolyploidy effect on miRNAs and lays a foundation for the elucidation of the miRNA-mediated regulatory mechanism in phenotypic variation in allopolyploids.

Arabidopsis thaliana hybrids have similar properties to hybrid crops, with greater biomass relative to the parents. We asked whether the greater biomass was due to increased photosynthetic efficiency per unit leaf area or to overall increased leaf area and increased total photosynthate per plant. We found that photosynthetic parameters (electron transport rate, CO2 assimilation rate, chlorophyll content, and chloroplast number) were unchanged on a leaf unit area and unit fresh weight basis between parents and hybrids, indicating that heterosis is not a result of increased photosynthetic efficiency. To investigate the possibility of increased leaf area producing more photosynthate per plant, we studied C24×Landsberg erecta (Ler) hybrids in detail. These hybrids have earlier germination and leaf growth than the parents, leading to a larger leaf area at any point in development of the plant. The developing leaves of the hybrids are significantly larger than those of the parents, with consequent greater production of photosynthate and an increased contribution to heterosis. The set of leaves contributing to heterosis changes as the plant develops; the four most recently emerged leaves make the greatest contribution. As a leaf matures, its contribution to heterosis attenuates. While photosynthesis per unit leaf area is unchanged at any stage of development in the hybrid, leaf area is greater and the amount of photosynthate per plant is increased., Early germination of hybrids leads to earlier leaf emergence and advanced leaf growth compared with parents, resulting in more photosynthate per plant and heterosis in vegetative growth, with no changes in unit leaf area photosynthesis.

The leaf and the flower are vital plant organs owing to their roles in photosynthesis and reproduction. Long non-coding RNAs (lncRNAs), microRNAs (miRNAs), and transcription factors (TFs) are very important to the development of these organs. Liriodendron chinense is a common ornamental tree species in southern China with an unusual leaf shape and tulip-like flowers. The genetic mechanisms underlying leaf and flower development in L. chinense and the miRNA-lncRNA-TF regulatory networks are poorly studied. Through the integration and analysis of different types of sequencing data, we identified the miRNA-lncRNA-TF regulatory networks that were related to leaf and flower development. These networks contained 105 miRNAs, 258 lncRNAs, 393 TFs, and 22 endogenous target mimics. Notably, lch-lnc7374-miR156h-SPL3 and lch-lnc7374-miR156j-SPL9 were potential regulators of stamen and pistil development in L. chinense, respectively. miRNA-lncRNA-mRNA regulatory networks were shown to impact anther development, male and female fertility, and petal color by regulating the biosynthesis of phenylpropanoid metabolites. Phenylpropanoid metabolite biosynthesis genes and TFs that were targeted by miRNAs and lncRNAs were differentially expressed in the leaf and flower. Moreover, RT-qPCR analysis confirmed 22 differentially expressed miRNAs, among which most of them showed obvious leaf or flower specificity; miR157a-SPL and miR160a-ARF module were verified by using RLM-RACE, and these two modules were related to leaf and flower development. These findings provide insight into the roles of miRNA-lncRNA-mRNA regulatory networks in organ development and function in L. chinense, and will facilitate further investigation into the regulatory mechanisms of leaf and flower development in L. chinense.

The use of biopesticides has gradually become essential to ensure food security and sustainable agricultural production. Nevertheless, the use of single biopesticides is frequently suboptimal in agricultural production given the diversity of biotic and abiotic stresses. The present study investigated the effects of two biopesticides, physcion and chitosan-oligosaccharide (COS), alone and in combination, on growth regulation and antioxidant potential of maize seedlings by seed coating. As suggested from the results, physcion significantly inhibited the growth of the shoots of maize seedlings due to the elevated respiration rate. However, COS significantly reduced the growth inhibition induced by physcion in maize seedlings by lowering the respiration rate and increasing the content of photosynthetic pigments and root vigor, which accounted for lower consumption of photosynthesis products, a higher photosynthetic rate and a greater nutrient absorption rate. Thus, an improved growth was identified. As indicated from the in-depth research, the application of physcion and COS combination is more effective in down-regulated the malondialdehyde (MDA) content by facilitating the activities of the antioxidative enzymes (i.e., superoxide dismutase (SOD), catalase (CAT) and guaiacol peroxidase (G-POD)). Such results indicated that the combined use of physcion and COS neither affected the normal growth of maize seedlings, but also synergistically improved the antioxidant potential of the maize plants, resulting in plants with high stress resistance. Thus, the combined use of physcion and COS by seed coating in maize production has great potential to ensure yield and sustainable production of maize.

This study identifies the transcriptional repressor NAC052, acting in H3K4 demethylation, as a regulator of leaf anatomical and morphological traits., In an effort to identify genetic regulators for the cell ontogeny around the veins in Arabidopsis thaliana leaves, an activation-tagged mutant line with altered leaf morphology and altered bundle sheath anatomy was characterized. This mutant had a small rosette area with wrinkled leaves and chlorotic leaf edges, as well as enhanced chloroplast numbers in the (pre-)bundle sheath tissue. It had a bundle-specific promoter from the gene GLYCINE DECARBOXYLASE SUBUNIT-T from the C4 species Flaveria trinervia (GLDTFt promoter) inserted in the coding region of the transcriptional repressor NAC052, functioning in H3K4 demethylation, in front of an alternative start codon in-frame with the natural start codon. Reconstruction of the mutation event of our activation-tagged line by creating a line expressing an N-terminally truncated sequence of NAC052 under control of the GLDTFt promoter confirmed the involvement of NAC052 in leaf development. Our study not only reveals leaf anatomic and transcriptomic effects of an N-terminally truncated NAC052 under control of the GLDTFt promoter, but also identifies NAC052 as a novel genetic regulator of leaf development.

Leaf development is crucial to establish the photosynthetic competency of plants. It is a process that requires coordinated changes in cell number and differentiation, transcriptomes, metabolomes and physiology. However, despite the importance of leaf formation for our major crops, early developmental processes for rice have not been comprehensively described. Here we detail the temporal developmental trajectory of early rice leaf development and connect morphological changes to metabolism. In particular, a developmental index based on the patterning of epidermal differentiation visualised by electron microscopy enabled high resolution staging of early growth for single primordium metabolite profiling. These data demonstrate that a switch in the constellation of tricarboxylic acid (TCA) cycle metabolites defines a narrow window towards the end of the P3 stage of leaf development. Taken in the context of other data in the literature, our results substantiate that this phase of rice leaf growth, equivalent to a change of primordium length from around 5 to 7.5 mm, defines a major shift in rice leaf determination towards a photosynthetically defined structure. We speculate that efforts to engineer rice leaf structure should focus on the developmental window prior to these determining events.HighlightRice leaves undergo a shift in fundamental metabolism during a very early and narrow developmental window which co-incides with them acquiring the ability to capture light for photosynthesis

Background Liriodendron chinense is a distinctive ornamental tree species due to its unique leaves and tulip-like flowers. The discovery of genes involved in leaf development and morphogenesis is critical for uncovering the underlying genetic basis of these traits. Genes in the AP2/ERF family are recognized as plant-specific transcription factors that contribute to plant growth, hormone-induced development, ethylene response factors, and stress responses. Results In this study, we identified 104 putative AP2/ERF genes in the recently released L. chinense genome and transcriptome database. In addition, all 104 genes were grouped into four subfamilies, the AP2, ERF, RAV, and Soloist subfamilies. This classification was further supported by the results of gene structure and conserved motif analyses. Intriguingly, after application of a series test of cluster analysis, three AP2 genes, LcERF 94, LcERF 96, and LcERF 98, were identified as tissue-specific in buds based on the expression profiles of various tissues. These results were further validated via RT-qPCR assays and were highly consistent with the STC analysis. We further investigated the dynamic changes of immature leaves by dissecting fresh shoots into seven discontinuous periods, which were empirically identified as shoot apical meristem (SAM), leaf primordia and tender leaf developmental stages according to the anatomic structure. Subsequently, these three candidates were highly expressed in SAM and leaf primordia but rarely in tender leaves, indicating that they were mainly involved in early leaf development and morphogenesis. Moreover, these three genes displayed nuclear subcellular localizations through the transient transformation of tobacco epidermal cells. Conclusions Overall, we identified 104 AP2/ERF family members at the genome-wide level and discerned three candidate genes that might participate in the development and morphogenesis of the leaf primordium in L. chinense.

After nitrogen treatments, plant leaves become narrower and thicker, and the chlorophyll content increases. However, the molecular mechanisms behind these regulations remain unknown. Here, we found that the changes in leaf width and thickness were largely compromised in the shade avoidance 3 (sav3) mutant. The SAV3 gene encodes an amino-transferase in the auxin biosynthesis pathway. Thus, the crosstalk between shade and nitrogen in Arabidopsis leaf development was investigated. Both hypocotyl elongation and leaf expansion promoted by the shade treatment were reduced by the high-N treatment; high-N-induced leaf narrowing and thickening were reduced by the shade treatment; and all of these developmental changes were largely compromised in the sav3 mutant. Shade treatment promoted SAV3 expression, while high-N treatment repressed SAV3 expression, which then increased or decreased auxin accumulation in cotyledons/leaves, respectively. SAV3 also regulates chlorophyll accumulation and nitrogen assimilation and thus may function as a master switch responsive to multiple environmental stimuli.

Background GROWTH-REGULATING FACTORs (GRFs), a type of plant-specific transcription factors, play important roles in regulating plant growth and development. Although GRF gene family has been identified in various plant species, a genome-wide analysis of this family in lettuce (Lactuca sativa L.) has not been reported yet. Results Here we identified 15 GRF genes in lettuce and performed comprehensive analysis of them, including chromosomal locations, gene structures, and conserved motifs. Through phylogenic analysis, we divided LsaGRFs into six groups. Transactivation assays and subcellular localization of LsaGRF5 showed that this protein is likely to act as a transcriptional factor in the cell nucleus. Furthermore, transgenic lettuce lines overexpressing LsaGRF5 exhibited larger leaves, while smaller leaves were observed in LsaMIR396a overexpression lines, in which LsaGRF5 was down-regulated. Conclusions These results in lettuce provide insight into the molecular mechanism of GRF gene family in regulating leaf growth and development and foundational information for genetic improvement of the lettuce variations specialized in leaf character.

Background Leaves, which are the most important organs of plants, can not only fix carbon sources through photosynthesis, but also absorb nutrients through transpiration. Leaf development directly determines the growth, flowering and fruiting of plants. There are many factors that affect leaf development, such as the growth environment, gene expression, and hormone synthesis. In this study, tomatoes were used to study the role of the transcription factor Solanum lycopersicum salt-related MYB1-like (SlSRM1-like) in the development of tomato leaves. Results Loss-of-function of the SlSRM1-like gene mediated by clustered, regularly interspaced, short palindromic repeat (CRISPR)/CRISPR-associated 9 (Cas9) resulted in abnormal tomato leaf morphology, including thinner leaves, wrinkled edges, raised veins, disordered edge veins, and left and right asymmetry. An analysis of the transcription levels of genes related to leaf development revealed that the expression of these genes was significantly altered in the SlSRM1-like mutants (SlSRM1-like-Ms). Moreover, the SlSRM1-like gene was expressed at higher transcription levels in young tissues than in old tissues, and its expression was also induced in response to auxin. In addition, the transcription levels of genes related to the auxin pathway, which regulates tomato growth and development, were severely affected in the SlSRM1-like-Ms. Therefore, it is hypothesized that the SlSRM1-like gene functions in the regulation of tomato leaf development through the auxin-related pathway. Conclusions In this study, we successfully knocked out the SlSRM1-like gene in the tomato variety Ailsa Craig using CRISPR technology and found that knockout of the SlSRM1-like gene resulted in abnormal development of tomato leaves. Further research indicated that SlSRM1-like regulated tomato leaf development through auxin-related pathways. The results provide an important reference for the functional study of other SRM1-like genes in plants and provide new insights into the regulation of leaf development in tomato and other plants.

Plasma membrane intrinsic protein (PIP) is one of the largest subfamilies of Aquaporins (AQPs) and plays an important role in plant growth and development, and resistance to abiotic stress. In this study, the full length of the EuPIP1;1 cDNA was cloned from Eucommia ulmoides using the rapid amplification of cDNA ends (RACE) method. The EuPIP1;1 gene was induced by drought treatment and expressed in all tested tissues, with the highest expression level in fruit. The subcellular localization showed that EuPIP1;1 was located in the plasma membrane. Constitutive overexpression of EuPIP1;1 in Arabidopsisthaliana could promote leaf growth and development, and accelerate bolting and flowering. Six genes related to growth and flowering (AtPIF4, AtTCP14, AtCRY1, AtCRY2, AtFCA and AtFT) were significantly up-regulated in transgenic lines. Further, EuPIP1;1 gene improved resistance to drought and salt stress in transgenic Arabidopsis. Under drought and salt stress treatment, the transgenic lines had a higher germination rate and accumulation of osmotic substances, lower membrane damage, and could maintain ion homeostasis. Our results suggest that EuPIP1;1 plays an essential role in plant growth and development and in the response to drought and salt stress.

Most flowering plant species contain at least two copies of the DEFECTIVE EMBRYO AND MERISTEMS (DEM) gene with the encoded DEM proteins lacking homology to proteins of known biochemical function. In tomato (Sl; Solanum lycopersicum), stable mutations in the SlDEM1 locus result in shoot and root meristem defects with the dem1 mutant failing to progress past the cotyledon stage of seedling development. Generation of a Somatic Mutagenesis of DEM1 (SMD) transformant line in tomato allowed for the characterization of SlDEM1 gene function past the seedling stage of vegetative development with SMD plants displaying a range of leaf development abnormalities. Further, the sectored or stable in planta expression of specific regions of the SlDEM1 coding sequence also resulted in the generation of tomato transformants that displayed a range of vegetative development defects, which when considered together with the dem1 mutant seedling and SMD transformant line phenotypic data, allowed for the assignment of SlDEM1 gene function to early embryo development, adaxial epidermis cell development, lateral leaf blade expansion, and mesophyll cell proliferation and differentiation.

Leaf senescence, the last stage of leaf development, is a type of postmitotic senescence and is characterized by the functional transition from nutrient assimilation to nutrient remobilization which is essential for plants’ fitness. The initiation and progression of leaf senescence are regulated by a variety of internal and external factors such as age, phytohormones, and environmental stresses. Significant breakthroughs in dissecting the molecular mechanisms underpinning leaf senescence have benefited from the identification of senescence-altered mutants through forward genetic screening and functional assessment of hundreds of senescence-associated genes (SAGs) via reverse genetic research in model plant Arabidopsis thaliana as well as in crop plants. Leaf senescence involves highly complex genetic programs that are tightly tuned by multiple layers of regulation, including chromatin and transcription regulation, post-transcriptional, translational and post-translational regulation. Due to the significant impact of leaf senescence on photosynthesis, nutrient remobilization, stress responses, and productivity, much effort has been made in devising strategies based on known senescence regulatory mechanisms to manipulate the initiation and progression of leaf senescence, aiming for higher yield, better quality, or improved horticultural performance in crop plants. This review aims to provide an overview of leaf senescence and discuss recent advances in multi-dimensional regulation of leaf senescence from genetic and molecular network perspectives. We also put forward the key issues that need to be addressed, including the nature of leaf age, functional stay-green trait, coordination between different regulatory pathways, source-sink relationship and nutrient remobilization, as well as translational researches on leaf senescence.

Wintergreen ferns keep their leaves for an entire year before replacing them with new leaves in the spring. The overwintering leaves of Dryopteris intermedia provide carbon to the new leaves, and if these old leaves cannot become prostrate before winter via the hinge that develops at the base of the petiole, they are frost damaged and broken, which may affect the development of the new leaves in the subsequent year. I compared the vernal development of new leaves in D. intermedia between plants whose old leaves were intact and those whose petioles had been experimentally broken in the fall to determine the importance of the softening of the petiole-base in old leaves to the development of new leaves. Compared to the control, plants whose old leaves had broken petioles had a one-week delay in the development of their new leaves. This delay demonstrates that the evolutionary development of the petiole hinge may have been critical to the functional benefit associated with new leaf development in the wintergreen leaf habit in ferns.

Increased frequency and severity of stressful events affects the growth patterns and functioning of trees which adjust their phenology to given conditions. Here, we analysed environmental effects (temperature, precipitation, VPD and SWC) on the timing of leaf phenology, seasonal stem radial growth patterns, and xylem and phloem anatomy of Quercus pubescens in the sub-Mediterranean in the period 2014%2019, when various adverse weather events occurred, i.e. spring drought in 2015, summer fire in 2016 and summer drought in 2017. Results showed that the timings of leaf and cambium phenology do not occur simultaneously in Q. pubescens, reflecting different environmental and internal constraints. Although year-to-year variability in the timings of leaf and cambial phenology exists, their chronological sequence is fairly fixed. Different effects of weather conditions on different stages of leaf development in spring were observed. Common climatic drivers (i.e., negative effect of hot and dry summers and a positive effect of increasing moisture availability in winter and summer) were found to affect the widths of xylem and phloem increments with more pronounced effect on late formed parts. A legacy effect of the timing of leaf and cambial phenology of the previous growing season on the timing of phenology of the following spring was confirmed. Rarely available phloem data permitted a comprehensive insight into the interlinkage of the timing of cambium and leaf phenology and adjustment strategies of vascular tissues in Mediterranean pubescent oak to various environmental constraints, including frequent extreme events (drought, fire). Our results suggest that predicted changes in autumn/winter and spring climatic conditions for this area could affect the timings of leaf and stem cambial phenology of Q. pubescens in the coming years, which would affect stem xylem and phloem structure and hydraulic properties, and ultimately its performance. Soavtorji: Jernej Jevšenak, Polona Hafner, Peter Prislan, Mitja Ferlan, Martina Lavrič, Dominik Vodnik, Klemen Eler. Bibliografija: str. 12-13. Abstract.

The growth of leaves and biosynthesis of characteristic secondary metabolites are critically important for tea production and quality control. However, little is known about the coordinated regulation of leaf development and catechin biosynthesis in tea plants. Here, we reported that TCP TFs are involved in both catechin biosynthesis and leaf development. An integrated analysis of catechin profiling and CsTCP expression in different tissues of plants under various environmental conditions at different developmental stages indicated significant correlations between the transcript levels of CIN-type TCPs and catechin production. CIN-type CsTCP3 and CsTCP4 and PCF-type CsTCP14 interacted with the MYB-bHLH-WD40 repeat (MBW) complex by forming a CsTCP3-CsTT8 heterodimer and modulating the transactivation activity of the promoters of anthocyanin synthase (CsANS1) and anthocyanidin reductase (CsANR1). Four types of microRNA/target modules, miR319b/CsTCP3-4, miR164b/CsCUC, miR396/CsGRF-GIF, and miR165b/HD-ZIPIII ones, were also identified and characterized for their functions in the regulation of the development of tea plant shoot tips and leaf shape. The results of these modules were reflected by their different expression patterns in developing buds and leaves that had distinctly different morphologies in three different tea plant varieties. Their roles in the regulation of catechin biosynthesis were also further verified by manipulation of microRNA319b (miR319b), which targets the transcripts of CsTCP3 and CsTCP4. Thus, CsTCPs represent at least one of these important groups of TFs that can integrate tea plant leaf development together with secondary metabolite biosynthesis. Our study provides new insight into shoot tip development and catechin production in tea plants and lays a foundation for further mechanistic understanding of the regulation of tea plant leaf development and secondary metabolism.

Background and AimsPrior work has examined cuticle function, composition and ultrastructure in many plant species, but much remains to be learned about how these features are related. This study aims to elucidate relationships between these features via analysis of cuticle development in adult maize (Zea mays L.) leaves, while also providing the most comprehensive investigation to date of the composition and ultrastructure of adult leaf cuticles in this important crop plant.MethodsWe examined water permeability, wax and cutin composition via gas chromatography, and ultrastructure via transmission electron microscopy, along the developmental gradient of partially expanded adult maize leaves, and analysed the relationships between these features.Key ResultsThe water barrier property of the adult maize leaf cuticle is acquired at the cessation of cell expansion. Wax types and chain lengths accumulate asynchronously over the course of development, while overall wax load does not vary. Cutin begins to accumulate prior to establishment of the water barrier and continues thereafter. Ultrastructurally, pavement cell cuticles consist of an epicuticular layer, and a thin cuticle proper that acquires an inner, osmiophilic layer during development.ConclusionsCuticular waxes of the adult maize leaf are dominated by alkanes and alkyl esters. Unexpectedly, these are localized mainly in the epicuticular layer. Establishment of the water barrier during development coincides with a switch from alkanes to esters as the major wax type, and the emergence of an osmiophilic (likely cutin-rich) layer of the cuticle proper. Thus, alkyl esters and the deposition of the cutin polyester are implicated as key components of the water barrier property of adult maize leaf cuticles.

Introduction.Aphanorrhegma (Physcomitrella) patens(Hedw.) Lindb. is an attractive model system for comparative analyses of leaf development because it evolved leaves (phyllids) independently toflowering plants, yet its genome contains homologues of many gene families that regulate angiosperm leaf development. In addition,A. patensphyllids are primarily a single cell layer thick, making it simple to identify the cellular basis of defects that perturb shape. Identification of gene functions in shape determination depends on like-for- like comparison of mutant versus wild-type plants.Key results.Here we show that, if heteroblasty is not perturbed, such comparisons should use phyllid L13 or above in the heteroblastic series, and fully expanded phyllids above P7 in the developmental series. Using a quantitative approach, we show that heteroblastic size variation reflects differences in cell proliferation rather than cell size and shape. A comparison of control topinA pinBmutant phyllid development verifies that PIN proteins promote cell proliferation and suppress expansion to determine phyllid shape.Conclusion.The results and approach that we have generated will be applicable to any study of A. patensphyllid development to reveal the cellular basis of phyllid size and shape variations.

The YABBY gene family plays a vital role in the polarity development of lateral organs. Here, we isolated a BoYABBY1 (BoYAB1) gene from Bambusa oldhamii and encodes for 167aa protein. This gene con...

Soil microbial communities hold great potential for sustainable and ecologically compatible agriculture. Although numerous plant-beneficial bacterial strains from a wide range of taxonomic groups have been reported, very little evidence is available on the plant-beneficial role of bacteria from the genus Caulobacter. Here, the mode of action of a Caulobacter strain, designated RHG1, which had originally been identified through a microbial screen for plant growth-promoting (PGP) bacteria in maize (Zea mays), is investigated in Arabidopsis thaliana. RHG1 colonized both roots and shoots of Arabidopsis, promoted lateral root formation in the root, and increased leaf number and leaf size in the shoot. The genome of RHG1 was sequenced and was utilized to look for PGP factors. Our data revealed that the bacterial production of nitric oxide, auxins, cytokinins, or 1-aminocyclopropane-1-carboxylate deaminase as PGP factors could be excluded. However, the analysis of brassinosteroid mutants suggests that an unknown PGP mechanism is involved that impinges directly or indirectly on the pathway of this growth hormone.

For clarifying the relationship between a leaf-to-fruit ratio (LFR) and photosynthesis, LFR manipulation was performed with Juglans regia cv. Xinxin2 in order to test the photosynthesis response to LFR in source leaves. Results showed that LFR with one and two leaves was positively correlated with net photosynthetic rate (PN), chlorophyll content, and specific leaf mass, implying extremely low LFR inhibited the leaf development. However, LFR with five leaves was negatively correlated with PN, positively correlated with starch, but not related to intercellular CO2 concentration, indicating the high LFR caused the nonstomatal limitation and feedback inhibition of photosynthetic production. No significant differences in PN between LFRs (with three and four leaves) probably indicated a balanced state of coordinated supply and demand between the source leaf and sink fruit. The above results indicated that the response of photosynthesis in the source leaves to LFR depends on the variation range of LFR.

MADS-box proteins are important transcription factors that play essential roles in various aspects of plant development, particularly in flower development. In this study, we performed the identification and functional characterization of CsMADS09 isolated from cucumber (Cucumis sativus L.). CsMADS09 contains a 648-bp open reading frame encoding 215 amino acid residues, and shares high sequence identities with the members of the AP1/FUL family of MADS-box proteins, especially the euAPETALA1 (euAP1) subclade. Many cis-elements related to plant development, stress response, and hormones were identified in the promoter region of CsMADS09. Quantitative real-time polymerase chain reaction results showed that CsMADS09 was mainly expressed in reproductive tissues such as male flowers and unexpanded ovaries, while its expression was low in roots and only traceable in fertilized ovaries. Moreover, the results revealed that CsMADS09 expression tended to decline during male flower development and stayed nearly constant during female flower development. Ectopic expression of CsMADS09 resulted in earlier flowering and abnormal leaf development in transgenic Arabidopsis. This study is the first functional analysis of an AP1-like gene from cucumber and provides some clues for revealing the molecular mechanisms of flower development in cucumber.

Vegetative growth in the form of tillers is crucial to final yield in winter wheat (Triticum aestivum L.). To understand the impact management practices have on tiller initiation, a study was conducted using two seeding rates (1.9 × 10⁶ vs. 6.8 × 10⁶ ha–¹) and two N timing applications (single vs. split). Tillers initiated in the fall made up the majority of spikes compared to tillers initiated from 1 January to the start of jointing (GS 30). Tillers initiated in March at either seeding rate produced very few kernels spike–¹, low kernel weight, and contributed little to yield. At the high seeding rate, tillers initiated prior to 1 January were responsible for more than 87% of the grain yield. Tillers produced in January– February produced 5 to 11% of the final yield, while tillers produced in March contributed less than 2%. In contrast, at the low seeding rate tillers produced in January–February made up 20 to almost 60% of the final yield. Overall, this study shows the timing and rate of leaf initiation impacts yield and yield components. Earlier tillers have an advantage in that they have shorter periods of leaf development that result in more leaf area which in turn supports more kernel spike–¹ and heavier kernels, thus more grain weight per spike. Timing of N (single vs. split) application resulted in no significant impact on tiller development, spike number, kernel number, kernel weight, or grain yield.

Maize (Zea mays L.) yield depends not only on the conversion and accumulation of carbohydrates in kernels, but also on the supply of carbohydrates by leaves. However, the carbon metabolism process in leaves can vary across different leaf regions and during the day and night. Hence, we used Weighted Gene Co-expression Network analysis (WGCNA) with the gene expression profiles of carbon metabolism to identify the modules and genes that may associate with particular regions in a leaf and time of day. There were a total of 45 samples of maize leaves that were taken from three different regions of a growing maize leaf at five time points. Robust Multi-array Average analysis was used to pre-process the raw data of GSE85963 (accession number), and quality control of data was based on Pearson correlation coefficients. We obtained eight co-expression network modules. The modules with the highest significance of association with LeafRegion and TimePoint were selected. Functional enrichment and gene-gene interaction analyses were conducted to acquire the hub genes and pathways in these significant modules. These results can support the findings of similar studies by providing evidence of potential module genes and enriched pathways associated with leaf development in maize.

Phenological stages of the “Pero de Cehegin” (Malus domestica Borkh) are described here according to the BBCH scale. Based on this general scale, the phenology of “Pero de Cehegin” showed 8 of the 10 main stages (0–9): bud development, leaf development, shoot development, inflorescence emergence, flowering, fruit development, fruit maturity and senescence. The correct identification of the phenological stages in plants is greatly important for the characterization of the variety, the management of the crop and the management of diseases and plagues as well. Thus, this study will provide knowledge and will help in the dissemination of knowledge of this peculiar apple variety among growers and scientists.

This report reveals that the LMI1-like and KNOX1 genes coordinately control the leaf development and different combinations of those genes which produce diverse leaf shapes including broad, lobed and compound leaves. Class I KNOTTED1-like homeobox (KNOX1) genes are involved in compound leaf development and are repressed by the ASYMMETRIC LEAVES1 (AS1)-AS2 complex. Cotton plants have a variety of leaf shapes, including broad leaves and lobed leaves. GhOKRA, a LATE MERISTEM IDENTITY 1 (LMI1)-like gene, controls the development of an okra leaf shape. We cloned the corresponding cotton homologs of Arabidopsis thaliana AS1 and AS2 and seven KNOX1 genes. Through virus-induced gene silencing technology, we found that either GhAS1 or GhAS2-silenced cotton plants showed a great change in leaf shape from okra leaves to trifoliolate dissected leaves. In the shoot tips of these plants, the expression of the cotton ortholog of Knotted in A. thaliana 1 (KNAT1), GhKNOTTED1-LIKE2/3/4 (GhKNL2/3/4), was increased. However, GhKNOX1s-silenced plants maintained the wild-type okra leaves. A novel dissected-like leaf in A. thaliana was further generated by crossing plants constitutively expressing GhOKRA with either as1-101 or as2-101 mutant plants. The dissected-like leaves showed two different leaf vein patterns. This report reveals that the LMI1-like and KNOX1 genes coordinately control leaf development, and different combinations of these genes produce diverse leaf shapes including broad leaves, lobed leaves and compound leaves. This is the first report on the artificial generation of compound leaves from simple leaves in cotton.

The effect of a prototype of humic bio-conditioner (H-BC) was assessed on the development of edaphic properties and the growth of maize plants in an edaphic material used as topsoil in the rehabilitation of soils in a coal mine in Colombia. The trial was carried out in a greenhouse, using pots with edaphic material treated with the addition of doses equivalent to 0 (control), 1, 2, and 4 Mg.ha−1 of H-BC; maize seeds were sown and followed up on for 60 days. Plant growth and soil biological, chemical, and physical variables were registered. The 4-Mg.ha−1 treatment maintained a significantly higher enzymatic activity than the control on day 60. The respiration of the soil treated with H-BC increased significantly, with the 4-Mg.ha−1 treatment standing out. The 2-Mg.ha−1 treatment induced the most noticeable changes in soil metabolic activity profiles. Increases in root and leaf development were observed in the treatment with 4 Mg.ha−1; apparently, this dose improved the absorption of Ca, K, and S by plants; the physical and soil aggregation indices increased significantly with 4 Mg.ha−1. The results indicate that H-BC can be an alternative as an enhancer of the edaphic material used in soil rehabilitation processes.

We investigated the photosynthesis and leaf development of cherry tomato seedlings grown under five different combinations of red and blue light provided by light-emitting diodes (LEDs). Fresh biomass increased significantly under treatments with blue light percentages of 50, 60, and 75%, with 50% blue-light-grown seedlings accumulating significantly more dry mass. The 25% blue-light-grown seedlings were obviously weaker than those from the other LED treatments. An increase in net photosynthetic rate upon blue light exposure (25–60%) was associated with increases in leaf mass per unit leaf area, leaf area, leaf density, stomatal number, chloroplast and mesophyll cell development, and chlorophyll contents. Our results imply that photosynthesis and leaf development in cherry tomato seedlings are associated with both the proportion and quantity of blue light.

Leaf senescence is the final step of leaf development and is usually accompanied by visible color changes from green to yellow or brown. Unlike the senescence of the whole body of animals and unicellular organisms, which is often associated with death, leaf senescence in plants requires highly integrative processes towards cell death with nutrient recycling and storage. Since leaf senescence plays pivotal roles in the production of plant biomass and grain yield, the mechanisms of degradation and relocation of macromolecules as well as the regulation of signaling and biosynthetic pathways have received much attention. The importance of the plant hormone ethylene in the onset of leaf senescence has been clearly documented. However, research has increasingly demonstrated that the function of ethylene in the regulation of leaf senescence is dependent on leaf development. This review raises the issue of how ethylene requires developmental regulators and focuses on the developmental aspect of leaf senescence. It also emphasizes the remarkable impact that developmental regulators have on regulating the onset of leaf senescence.

Leaf area affects light interception, carbon assimilation and plant growth. How maize leaf development and expansion is affected by temperature under different evaporative demand conditions is not well understood. Effects of three temperatures (21, 27 and 32 °C) under high and low evaporative demand conditions were tested in growth chambers. Leaf expansion rate (LER), leaf appearance rate (LAR), leaf number, plant height, photosynthesis (A), net assimilation rate (NAR), stomatal conductance (gs), and transpiration (E) increased with increasing temperature under low evaporative demand environments. Under high evaporative demand, while there was an increase with temperature until 27 °C, at 32 °C there was a decrease in LER, plant height, A, NAR, gs, and E. However, the variation in the rate of leaf appearance appears to be linked to temperature but not VPD. The development of stomata and epidermal cells were affected by VPD with large size stomata and more epidermal cells under low VPD. The differential responses of LER to low and high evaporative demands could be attributed to changes in expression of Expansin A2, A4, and B1 genes and XTH23. The significant effect of temperature and VPD on the expression of vacuolar H + pyrophosphatase and teosinte branched gene was detected. Overall, we found a negative effect of high VPD due to high evaporative demand for maize leaf expansion and development.

The vitality and the development in the seedling stage is crucial in winter cereal’s life cycle, especially before and during winter. It has been reported that rapid seedling establishment and early growth may lead to higher crop yield. Localization of cereal genome regions is not often analysed in the seedling stage. The aim of this study was to identify winter triticale genome regions (QTL) associated with seedling leaves development. Based on ‘Hewo’ x ‘Magnat’ DH lines population genetic map composed of 3539 molecular markers assigned to 20 linkage groups with 4997.4 cM map length, in total 40 loci were identified by a composite interval mapping (CIM). Among them, 22 loci appeared in at least two experiments, were common for all analyzed traits as well as were identified on wheat chromosome 4B and on rye chromosomes 1R, 4R, 5R and 6R. Those loci explained up to 21.7% of phenotypic variation (Qwsl.hm.4R.2) and had LOD value up to 31.1 (Qlsl.hm.5R.1). The results of QTLs of seedling leaves development could be successively associated with QTLs of the freezing and fungal infection seedlings tolerance identified in this mapping population.