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Expanded agriculture production is required to support the world's population but can impose substantial environmental and climate change costs, particularly with intensifying animal production and protein demand. Shifting from an animal- to a plant-based protein diet has numerous health benefits. Soybean (Glycine max (L.) Merr.) is a major source of protein for human food and animal feed; improved soybean protein content and amino acid composition could provide high-quality soymeal for animal feed, healthier human foods, and a reduced carbon footprint. Nonetheless, during the soybean genome evolution, a balance was established between the amount of seed protein, oil, and carbohydrate content, burdening the development of soybean cultivars with high proteins. We isolated two high-seed protein (HP) soybean mutants, HP1 and HP2, with improved seed amino acid composition and stachyose content, pointing to their involvement in controlling seed rebalancing phenomenon. HP1 encodes ß-conglycinin (GmCG-1) and HP2 encodes Sucrose Binding Protein (GmSBP-1), which are both highly expressed in soybean seeds. Mutations in GmSBP-1, GmCG-1, and the paralog GmCG-2 resulted in increased protein levels, confirming their role as general regulators of seed protein content, amino acid seed composition, and seed vigor. Biodiversity analysis of GmCG and GmSBP across 108 soybean accessions revealed haplotypes correlated with protein and seed carbohydrate content. Furthermore, our data revealed an unprecedented role of GmCG and GmSBP proteins in improving seed vigor, crude protein, and amino acid digestibility. Since GmSBP and GmCG are present in most seed plants analyzed, these genes could be targeted to improve multiple seed traits.
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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.
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In flowering plants, the predominant sexual morph is hermaphroditism, and the emergence of unisexuality is poorly understood. Using Cucumis melo (melon) as a model system, we explore the mechanisms driving sexual forms. We identify a spontaneous mutant exhibiting a transition from bisexual to unisexual male flower, and identify the causal mutation as a Harbinger transposon impairing the expression of Ethylene Insensitive 2 (CmEIN2) gene. Genetics and transcriptomic analysis reveal a dual role of CmEIN2 in both sex determination and fruit shape formation. Upon expression of CmACS11, EIN2 is recruited to repress the expression of the carpel inhibitor, CmWIP1. Subsequently, EIN2 is recruited to mediate stamina inhibition. Following the sex determination phase, EIN2 promotes fruit shape elongation. Genome-wide analysis reveals that Harbinger transposon mobilization is triggered by environmental cues, and integrates preferentially in active chromatin, particularly within promoter regions. Characterization of a large collection of melon germplasm points to active transpositions in the wild, compared to cultivated accessions. Our study underscores the association between chromatin dynamics and the temporal aspects of mobile genetic element insertions, providing valuable insights into plant adaptation and crop genome evolution.
Assuntos
Elementos de DNA Transponíveis , Etilenos , Flores , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas , Elementos de DNA Transponíveis/genética , Etilenos/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Flores/genética , Flores/crescimento & desenvolvimento , Transdução de Sinais/genética , Cucumis melo/genética , Cucumis melo/metabolismo , Frutas/genética , Frutas/crescimento & desenvolvimento , MutaçãoRESUMO
Sex determination evolved to control the development of unisexual flowers. In agriculture, it conditions how plants are cultivated and bred. We investigated how female flowers develop in monoecious cucurbits. We discovered in melon, Cucumis melo, a mechanism in which ethylene produced in the carpel is perceived in the stamen primordia through spatially differentially expressed ethylene receptors. Subsequently, the CmEIN3/CmEIL1 ethylene signalling module, in stamen primordia, activates the expression of CmHB40, a transcription factor that downregulates genes required for stamen development and upregulates genes associated with organ senescence. Investigation of melon genetic biodiversity revealed a haplotype, originating in Africa, altered in EIN3/EIL1 binding to CmHB40 promoter and associated with bisexual flower development. In contrast to other bisexual mutants in cucurbits, CmHB40 mutations do not alter fruit shape. By disentangling fruit shape and sex-determination pathways, our work opens up new avenues in plant breeding.
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Cucurbitaceae , Proteínas de Plantas , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Melhoramento Vegetal , Etilenos/metabolismo , Cucurbitaceae/genética , Flores , Regulação da Expressão Gênica de PlantasRESUMO
Melon is a recalcitrant plant for stable genetic transformation. Various protocols have been tried to improve melon transformation efficiency; however, it remains significantly low compared to other plants such as tomato. In this study, the primary focus was on the optimization of key parameters during the inoculation and co-culture steps of the genetic transformation protocol. Our results showed that immersing the explants in the inoculation medium for 20 min significantly enhanced transformation efficiency. During the co-culture step, the use of filer paper, 10 mM 2-(N-morpholino)-ethanesulfonic acid (MES), and a temperature of 24 °C significantly enhanced the melon transformation efficiency. Furthermore, the impact of different ethylene inhibitors and absorbers on the transformation efficiency of various melon varieties was explored. Our findings revealed that the use of these compounds led to a significant improvement in the transformation efficiency of the tested melon varieties. Subsequently, using our improved protocol and reporter-gene construct, diploid transgenic melons successfully generated. The efficiency of plant genetic transformation ranged from 3.73 to 4.83%. Expanding the scope of our investigation, the optimized protocol was applied to generate stable gene-edited melon lines using the Clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9)-mediated cytosine base editor and obtained melon lines with editions (C-to-T and C-to-G) in the eukaryotic translation initiation factor 4E, CmeIF4E gene. In conclusion, the optimized melon transformation protocol, along with the utilization of the CRISPR/Cas9-mediated cytosine base editor, provides a reliable framework for functional gene engineering in melon. These advancements hold significant promise for furthering genetic research and facilitating crop improvement in this economically important plant species.
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Cucumis melo , Cucurbitaceae , Edição de Genes/métodos , Sistemas CRISPR-Cas/genética , Cucumis melo/genética , Cucurbitaceae/genética , Plantas/genéticaRESUMO
Male and female unisexual flowers evolved from hermaphroditic ancestors, and control of flower sex is useful for plant breeding. We isolated a female-to-male sex transition mutant in melon and identified the causal gene as the carpel identity gene <i>CRABS CLAW (CRC)</i>. We show that the master regulator of sex determination in cucurbits, the transcription factor <i>WIP1</i> whose expression orchestrates male flower development, recruits the corepressor TOPLESS to the <i>CRC</i> promoter to suppress its expression through histone deacetylation. Impairing TOPLESS-WIP1 physical interaction leads to <i>CRC</i> expression, carpel determination, and consequently the expression of the stamina inhibitor, the aminocyclopropane-1-carboxylic acid synthase 7 (<i>CmACS7</i>), leading to female flower development. Our findings suggest that sex genes evolved to interfere with flower meristematic function, leading to unisexual flower development.
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Cucurbitaceae , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas , Processos de Determinação Sexual , Flores/genética , Flores/crescimento & desenvolvimento , Meristema/metabolismo , Melhoramento Vegetal , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Cucurbitaceae/genética , Cucurbitaceae/crescimento & desenvolvimentoRESUMO
Flower morphologies shape the accessibility to nectar and pollen, two major traits that determine plant-pollinator interactions and reproductive success. Melon is an economically important crop whose reproduction is completely pollinator-dependent and, as such, is a valuable model for studying crop-ecological functions. High-resolution imaging techniques, such as micro-computed tomography (micro-CT), have recently become popular for phenotyping in plant science. Here, we implemented micro-CT to study floral morphology and honey bees in the context of nectar-related traits without a sample preparation to improve the phenotyping precision and quality. We generated high-quality 3D models of melon male and female flowers and compared the geometric measures. Micro-CT allowed for a relatively easy and rapid generation of 3D volumetric data on nectar, nectary, flower, and honey bee body sizes. A comparative analysis of male and female flowers showed a strong positive correlation between the nectar gland volume and the volume of the secreted nectar. We modeled the nectar level inside the flower and reconstructed a 3D model of the accessibility by honey bees. By combining data on flower morphology, the honey bee size and nectar volume, this protocol can be used to assess the flower accessibility to pollinators in a high resolution, and can readily carry out genotypes comparative analysis to identify nectar-pollination-related traits.
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Néctar de Plantas , Polinização , Abelhas , Animais , Microtomografia por Raio-X , Raios X , Flores/anatomia & histologiaRESUMO
One of the most important challenges facing current and future generations is how climate change and continuous population growth adversely affect food security. To address this, the food system needs a complete transformation where more is produced in non-optimal and space-limited areas while reducing negative environmental impacts. Fruits and vegetables, essential for human health, are high-value-added crops, which are grown in both greenhouses and open field environments. Here, we review potential practices to reduce the impact of climate variation and ecosystem damages on fruit and vegetable crop yield, as well as highlight current bottlenecks for indoor and outdoor agrosystems. To obtain sustainability, high-tech greenhouses are increasingly important and biotechnological means are becoming instrumental in designing the crops of tomorrow. We discuss key traits that need to be studied to improve agrosystem sustainability and fruit yield.
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Frutas , Verduras , Humanos , Agricultura , Ecossistema , Abastecimento de Alimentos , Produtos AgrícolasRESUMO
Development of plant organs is a highly organized process. In Arabidopsis, proper root development requires that distinct cell types and tissue layers are specified and formed in a restricted manner in space and over time. Despite its importance, genetic controls underlying such regularity remain elusive. Here we found that WIP genes expressed in the embryo and suspensor functionally oppose those expressed in the surrounding maternal tissues to orchestrate cell division orientation and cell fate specification in the embryonic root, thereby promoting regular root formation. The maternal WIPs act non-cell autonomously to repress root cell fate specification through SIMILAR TO RADICAL-INDUCED CELL DEATH ONE (SRO) family members. When losing all WIPs, root cells divide irregularly in the early embryo, but this barely alters their fate specification and the morphology of post-embryonic roots. Our results reveal cross-communication between the embryonic and maternal WIPs in controlling root development.
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Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Diferenciação Celular , Divisão Celular/genética , Regulação da Expressão Gênica de Plantas , Raízes de Plantas/metabolismo , Plantas/metabolismoRESUMO
Shapes of vegetables and fruits are the result of adaptive evolution and human selection. Modules controlling organ shape have been identified. However, little is known about signals coordinating organ development and shape. Here, we describe the characterization of a melon mutation rf1, leading to round fruit. Histological analysis of rf1 flower and fruits revealed fruit shape is determined at flower stage 8, after sex determination and before flower fertilization. Using positional cloning, we identified the causal gene as the monoecy sex determination gene CmACS7, and survey of melon germplasms showed strong association between fruit shape and sexual types. We show that CmACS7-mediated ethylene production in carpel primordia enhances cell expansion and represses cell division, leading to elongated fruit. Cell size is known to rise as a result of endoreduplication. At stage 8 and anthesis, we found no variation in ploidy levels between female and hermaphrodite flowers, ruling out endoreduplication as a factor in fruit shape determination. To pinpoint the gene networks controlling elongated versus round fruit phenotype, we analyzed the transcriptomes of laser capture microdissected carpels of wild-type and rf1 mutant. These high-resolution spatiotemporal gene expression dynamics revealed the implication of two regulatory modules. The first module implicates E2F-DP transcription factors, controlling cell elongation versus cell division. The second module implicates OVATE- and TRM5-related proteins, controlling cell division patterns. Our finding highlights the dual role of ethylene in the inhibition of the stamina development and the elongation of ovary and fruit in cucurbits.
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Cucurbitaceae , Frutas , Cucurbitaceae/genética , Cucurbitaceae/metabolismo , Etilenos/metabolismo , Flores , Regulação da Expressão Gênica de Plantas , Fenótipo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismoRESUMO
Cucumis melo displays a large diversity of horticultural groups with cantaloupe melon the most cultivated type. Using a combination of single-molecule sequencing, 10X Genomics link-reads, high-density optical and genetic maps, and chromosome conformation capture (Hi-C), we assembled a chromosome scale C. melo var. cantalupensis Charentais mono genome. Integration of RNA-seq, MeDip-seq, ChIP-seq, and Hi-C data revealed a widespread compartmentalization of the melon genome, segregating constitutive heterochromatin and euchromatin. Genome-wide comparative and evolutionary analysis between melon botanical groups identified Charentais mono genome increasingly more divergent from Harukei-3 (reticulatus), Payzawat (inodorus), and HS (ssp. agrestis) genomes. To assess the paleohistory of the Cucurbitaceae, we reconstructed the ancestral Cucurbitaceae karyotype and compared it to sequenced cucurbit genomes. In contrast to other species that experienced massive chromosome shuffling, melon has retained the ancestral genome structure. We provide comprehensive genomic resources and new insights in the diversity of melon horticultural groups and evolution of cucurbits.
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In monoecious melon (Cucumis melo), sex is determined by the differential expression of sex determination genes (SDGs) and adoption of sex-specific transcriptional programs. Histone modifications such as H3K27me3 have been previously shown to be a hallmark associated to unisexual flower development in melon; yet, no genetic approaches have been conducted for elucidating the roles of H3K27me3 writers, readers, and erasers in this process. Here we show that melon homologs to Arabidopsis LHP1, CmLHP1A and B, redundantly control several aspects of plant development, including sex expression. Cmlhp1ab double mutants displayed an overall loss and redistribution of H3K27me3, leading to a deregulation of genes involved in hormone responses, plant architecture, and flower development. Consequently, double mutants display pleiotropic phenotypes and, interestingly, a general increase of the male:female ratio. We associated this phenomenon with a general deregulation of some hormonal response genes and a local activation of male-promoting SDGs and MADS-box transcription factors. Altogether, these results reveal a novel function for CmLHP1 proteins in maintenance of monoecy and provide novel insights into the polycomb-mediated epigenomic regulation of sex lability in plants.
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Arabidopsis , Cucumis melo , Cucurbitaceae , Arabidopsis/genética , Cucumis melo/genética , Cucumis melo/metabolismo , Cucurbitaceae/genética , Regulação da Expressão Gênica de Plantas/genética , Histonas/metabolismo , Desenvolvimento Vegetal , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismoRESUMO
Sclareol, an antifungal specialized metabolite produced by clary sage, Salvia sclarea, is the starting plant natural molecule used for the hemisynthesis of the perfume ingredient ambroxide. Sclareol is mainly produced in clary sage flower calyces; however, the cellular localization of the sclareol biosynthesis remains unknown. To elucidate the site of sclareol biosynthesis, we analyzed its spatial distribution in the clary sage calyx epidermis using laser desorption/ionization mass spectrometry imaging (LDI-FTICR-MSI) and investigated the expression profile of sclareol biosynthesis genes in isolated glandular trichomes (GTs). We showed that sclareol specifically accumulates in GTs' gland cells in which sclareol biosynthesis genes are strongly expressed. We next isolated a glabrous beardless mutant and demonstrate that more than 90% of the sclareol is produced by the large capitate GTs. Feeding experiments, using 1-13C-glucose, and specific enzyme inhibitors further revealed that the methylerythritol-phosphate (MEP) biosynthetic pathway is the main source of isopentenyl diphosphate (IPP) precursor used for the biosynthesis of sclareol. Our findings demonstrate that sclareol is an MEP-derived diterpene produced by large capitate GTs in clary sage emphasing the role of GTs as biofactories dedicated to the production of specialized metabolites.
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Fruit maturation and softening are critical traits that control fruit shelf-life. In the climacteric tomato (Solanum lycopersicum L.) fruit, ethylene plays a key role in fruit ripening and softening. We characterized two related proteins with contrasting impact on ethylene production, ACC oxidase 1 (SlACO1) and SlE8. We found SlACO1 and SlE8 to be highly expressed during fruit ripening. To identify loss-of-function alleles, we analysed the tomato genetic diversity but we did not find any natural mutations impairing the function of these proteins. We also found the two loci evolving under purifying selection. To engineer hypomorphic alleles, we used TILLING (target-induced local lesions in genomes) to screen a tomato ethylmethane sulfonate-mutagenized population. We found 13 mutants that we phenotyped for ethylene production, shelf-life, firmness, conductivity, and soluble solid content in tomato fruits. The data demonstrated that slaco1-1 and slaco1-2 alleles could be used to improve fruit shelf-life, and that sle8-1 and sle8-2 alleles could be used to accelerate ripening. This study highlights further the importance of SlACO1 and SlE8 in ethylene production in tomato fruit and how they might be used for post-harvest fruit preservation or speeding up fruit maturation.
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Solanum lycopersicum , Etilenos , Frutas/genética , Frutas/metabolismo , Regulação da Expressão Gênica de Plantas , Solanum lycopersicum/genética , Solanum lycopersicum/metabolismo , Mutação , Fenótipo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismoRESUMO
A road-map of the genetic and phenotypic diversities in both crops and their wild related species can help identifying valuable genetic resources for further crop breeding. The clary sage (Salvia sclarea L.), a perfume, medicinal and aromatic plant, is used for sclareol production and ornamental purposes. Despite its wide use in the field of cosmetics, the phenotypic and genetic diversity of wild and cultivated clary sages remains to be explored. We characterized the genetic and phenotypic variation of a collection of six wild S. sclarea populations from Croatia, sampled along an altitudinal gradient, and, of populations of three S. sclarea cultivars. We showed low level of genetic diversity for the two S. sclarea traditional cultivars used for essential oil production and for ornamental purposes, respectively. In contrast, a recent cultivar resulting from new breeding methods, which involve hybridizations among several genotypes rather than traditional recurrent selection and self-crosses over time, showed high genetic diversity. We also observed a marked phenotypic differentiation for the ornamental clary sage compared with other cultivated and wild clary sages. Instead, the two cultivars used for essential oil production, a traditional and a recent one, respectively, were not phenotypically differentiated from the wild Croatian populations. Our results also featured some wild populations with high sclareol content and early-flowering phenotypes as good candidates for future breeding programs. This study opens up perspectives for basic research aiming at understanding the impact of breeding methods on clary sage evolution, and highlights interesting avenues for clary breeding programs.
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Variação Biológica da População , Variação Genética , Perfumes , Melhoramento Vegetal , Salvia/genética , Óleos VoláteisRESUMO
HEAT SHOCK FACTOR A2 (HSFA2) is a regulator of multiple environmental stress responses required for stress acclimation. We analyzed HSFA2 co-regulated genes and identified 43 genes strongly co-regulated with HSFA2 during multiple stresses. Motif enrichment analysis revealed an over-representation of the site II element (SIIE) in the promoters of these genes. In a yeast 1-hybrid screen with the SIIE, we identified the closely related R2R3-MYB transcription factors TT2 and MYB5. We found overexpression of MYB5 or TT2 rendered plants heat stress tolerant. In contrast, tt2, myb5, and tt2/myb5 loss of function mutants showed heat stress hypersensitivity. Transient expression assays confirmed that MYB5 and TT2 can regulate the HSFA2 promoter together with the other members of the MBW complex, TT8 and TRANSPARENT TESTA GLABRA 1 (TTG1) and that the SIIE was involved in this regulation. Transcriptomic analysis revealed that TT2/MYB5 target promoters were enriched in SIIE. Overall, we report a new function of TT2 and MYB5 in stress resistance and a role in SIIE-mediated HSFA2 regulation.
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Proteínas de Arabidopsis/genética , Proteínas de Ligação a DNA/genética , Resposta ao Choque Térmico , Arabidopsis , Proteínas de Arabidopsis/metabolismo , Proteínas de Ligação a DNA/metabolismo , Regulação da Expressão Gênica de Plantas , Fatores de Transcrição de Choque Térmico/genética , Fatores de Transcrição de Choque Térmico/metabolismo , Mutação com Perda de Função , Sementes/genética , Sementes/crescimento & desenvolvimento , TranscriptomaRESUMO
Fruit set is inhibited by adverse temperatures, with consequences on yield. We isolated a tomato mutant producing fruits under non-permissive hot temperatures and identified the causal gene as SlHB15A, belonging to class III homeodomain leucine-zipper transcription factors. SlHB15A loss-of-function mutants display aberrant ovule development that mimics transcriptional changes occurring in fertilized ovules and leads to parthenocarpic fruit set under optimal and non-permissive temperatures, in field and greenhouse conditions. Under cold growing conditions, SlHB15A is subjected to conditional haploinsufficiency and recessive dosage sensitivity controlled by microRNA 166 (miR166). Knockdown of SlHB15A alleles by miR166 leads to a continuum of aberrant ovules correlating with parthenocarpic fruit set. Consistent with this, plants harboring an Slhb15a-miRNA166-resistant allele developed normal ovules and were unable to set parthenocarpic fruit under cold conditions. DNA affinity purification sequencing and RNA-sequencing analyses revealed that SlHB15A is a bifunctional transcription factor expressed in the ovule integument. SlHB15A binds to the promoters of auxin-related genes to repress auxin signaling and to the promoters of ethylene-related genes to activate their expression. A survey of tomato genetic biodiversity identified pat and pat-1, two historical parthenocarpic mutants, as alleles of SlHB15A. Taken together, our findings demonstrate the role of SlHB15A as a sentinel to prevent fruit set in the absence of fertilization and provide a mean to enhance fruiting under extreme temperatures.
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MicroRNAs/fisiologia , Proteínas de Plantas/fisiologia , RNA de Plantas/fisiologia , Solanum lycopersicum/crescimento & desenvolvimento , Fatores de Transcrição/fisiologia , Perfilação da Expressão Gênica , Zíper de Leucina , Solanum lycopersicum/genética , Partenogênese/genética , Proteínas de Plantas/genéticaRESUMO
Nectar is the most important reward offered by flowering plants to pollinators for pollination services. Since pollinator decline has emerged as a major threat for agriculture, and the food demand is growing globally, studying the nectar gland is of utmost importance. Although the genetic mechanisms that control the development of angiosperm flowers have been quite well understood for many years, the development and maturation of the nectar gland and the secretion of nectar in synchrony with the maturation of the sexual organs appears to be one of the flower's best-kept secrets. Here we review key findings controlling these processes. We also raise key questions that need to be addressed to develop crop ecological functions that take into consideration pollinators' needs.
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Néctar de Plantas , Polinização , Flores/genética , Polinização/genética , ReproduçãoRESUMO
In cucurbits, CmWIP1 is a master gene controlling sex determination. To bring new insight in the function of CmWIP1, we investigated two Arabidopsis WIP transcription factors, AtWIP1/TT1 and AtWIP2/NTT. Using an inducible system we showed that WIPs are powerful inhibitor of growth and inducer of cell death. Using ChIP-seq and RNA-seq we revealed that most of the up-regulated genes bound by WIPs display a W-box motif, associated with stress signaling. In contrast, the down-regulated genes contain a GAGA motif, a known target of polycomb repressive complex. To validate the role of WIP proteins in inhibition of growth, we expressed AtWIP1/TT1 in carpel primordia and obtained male flowers, mimicking CmWIP1 function in melon. Using other promoters, we further demonstrated that WIPs can trigger growth arrest of both vegetative and reproductive organs. Our data supports an evolutionary conserved role of WIPs in recruiting gene networks controlling growth and adaptation to stress.