The proper flowering time of rose(Rosa hybrida)is vital for the market value of this horticultural crop,but the mechanism regulating this trait is largely unclear.Here,we found that the transcription factor SQUAMOSA P...The proper flowering time of rose(Rosa hybrida)is vital for the market value of this horticultural crop,but the mechanism regulating this trait is largely unclear.Here,we found that the transcription factor SQUAMOSA PROMOTER BINDING PROTEIN-LIKE4(RhSPL4)positively regulates flowering time in rose.Transient silencing or overexpression transgenic rose plants of RhSPL4 exhibited delayed or early flowering,respectively.Analysis of transcriptome data from transgenic lines overexpressing RhSPL4 compared to the wild type indicated that differentially expressed genes were significantly enriched in the circadian rhythm pathway.Among the proteins encoded by these genes,RhSPL4 binds to the promoter of PSEUDO-RESPONSE REGULATOR 5-LIKE(RhPRR5L),as revealed in yeast one-hybrid,dual-Luciferase/Renilla luciferase reporter,chromatin immunoprecipitation-quantitative PCR and electrophoretic mobility shift assay.Furthermore,RhSPL4 specifically binds to the478 to441 bp region of the RhPRR5L promoter and activates its transcription.The silencing of RhPRR5L delayed flowering time in rose,resembling the phenotype of RhSPL4-silenced plants.Together,these results indicate that the RhSPL4-RhPRR5L module positively regulates flowering time in rose,laying the foundation for the genetic improvement of flowering time in this important horticultural crop.展开更多
Appropriate flowering time in rapeseed(Brassica napus L.)is vital for preventing losses from weather,diseases,and pests.However,the molecular basis of its regulation remains largely unknown.Here,a genome-wide associat...Appropriate flowering time in rapeseed(Brassica napus L.)is vital for preventing losses from weather,diseases,and pests.However,the molecular basis of its regulation remains largely unknown.Here,a genome-wide association study identifies BnaC09.FUL,a MADS-box transcription factor,as a promising candidate gene regulating flowering time in B.napus.BnaC09.FUL expression increases sharply in B.napus shoot apices near bolting.BnaC09.FUL overexpression results in early flowering,while BnaFUL mutation causes delayed flowering in B.napus.A zinc finger transcription factor,BnaC06.WIP2,is identified as an interaction partner of BnaC09.FUL,and BnaC06.WIP2 overexpression delays flowering in B.napus,with RNA sequencing revealing its influence on the expression of many flowering-associated genes.We further demonstrate that BnaC06.WIP2 directly represses the expression of BnaA05.SOC1,BnaC03.SOC1,BnaC04.SOC1,BnaC06.FT,BnaA06.LFY,BnaC07.FUL,BnaA08.CAL,and BnaC03.CAL and indirectly inhibits the expression of other flowering time-related genes.Genetic and molecular investigations highlight the antagonistic relationship between BnaC09.FUL and BnaC06.WIP2 in regulating the flowering time in B.napus through direct regulation of the expression of BnaC03.SOC1,BnaA08.CAL,and BnaC03.CAL.Overall,our findings provide a mechanism by which the BnaC09.FUL–BnaC06.WIP2 transcriptional regulatory module controls the flowering time in B.napus.展开更多
Properly regulated flowering time is pivotal for successful plant reproduction.The floral transition from vegetative growth to reproductive growth is regulated by a complex gene regulatory network that integrates envi...Properly regulated flowering time is pivotal for successful plant reproduction.The floral transition from vegetative growth to reproductive growth is regulated by a complex gene regulatory network that integrates environmental signals and internal conditions to ensure that flowering takes place under favorable conditions.Brassica rapa is a diploid Cruciferae species that includes several varieties that are cultivated as vegetable or oil crops.Flowering time is one of the most important agricultural traits of B.rapa crops because of its influence on yield and quality.The transition to flowering in B.rapa is regulated by several environmental and developmental cues,which are perceived by several signaling pathways,including the vernalization pathway,the autonomous pathway,the circadian clock,the thermosensory pathway,and gibberellin(GA)signaling.These signals are integrated to control the expression of floral integrators BrFTs and BrSOC1s to regulate flowering.In this review,we summarized current research advances on the molecular mechanisms that govern flowering time regulation in B.rapa and compare this to what is known in Arabidopsis.展开更多
Flowering time is important for adaptation of soybean(Glycine max)to different environments.Here,we conducted a genome-wide association study of flowering time using a panel of 1490 cultivated soybean accessions.We id...Flowering time is important for adaptation of soybean(Glycine max)to different environments.Here,we conducted a genome-wide association study of flowering time using a panel of 1490 cultivated soybean accessions.We identified three strong signals at the qFT02-2 locus(Chr02:12037319–12238569),which were associated with flowering time in three environments:Gongzhuling,Mengcheng,and Nanchang.By analyzing linkage disequilibrium,gene expression patterns,gene annotation,and the diversity of variants,we identified an AP1 homolog as the candidate gene for the qFT02-2 locus,which we named GmAP1d.Only one nonsynonymous polymorphism existed among 1490 soybean accessions at position Chr02:12087053.Accessions carrying the Chr02:12087053-T allele flowered significantly earlier than those carrying the Chr02:12087053-A allele.Thus,we developed a cleaved amplified polymorphic sequence(CAPS)marker for the SNP at Chr02:12087053,which is suitable for marker-assisted breeding of flowering time.Knockout of GmAP1d in the‘Williams 82’background by gene editing promoted flowering under long-day conditions,confirming that GmAP1d is the causal gene for qFT02-2.An analysis of the region surrounding GmAP1d revealed that GmAP1d was artificially selected during the genetic improvement of soybean.Through stepwise selection,the proportion of modern cultivars carrying the Chr02:12087053-T allele has increased,and this allele has become nearly fixed(95%)in northern China.These findings provide a theoretical basis for better understanding the molecular regulatory mechanism of flowering time in soybean and a target gene that can be used for breeding modern soybean cultivars adapted to different latitudes.展开更多
Soybean(Glycine max)is a short-day crop whose flowering time is regulated by photoperiod.The longjuvenile trait extends its vegetative phase and increases yield under short-day conditions.Natural variation in J,the ma...Soybean(Glycine max)is a short-day crop whose flowering time is regulated by photoperiod.The longjuvenile trait extends its vegetative phase and increases yield under short-day conditions.Natural variation in J,the major locus controlling this trait,modulates flowering time.We report that the three J-family genes influence soybean flowering time,with the triple mutant Guangzhou Mammoth-2 flowering late under short days by inhibiting transcription of E1-family genes.J-family genes offer promising allelic combinations for breeding.展开更多
We investigated the microRNA172(miR172)-mediated regulatory network for the perception of changes in external and endogenous signals to identify a universally applicable floral regulation system in ornamental plants, ...We investigated the microRNA172(miR172)-mediated regulatory network for the perception of changes in external and endogenous signals to identify a universally applicable floral regulation system in ornamental plants, manipulation of which could be economically beneficial. Transgenic gloxinia plants, in which miR172 was either overexpressed or suppressed, were generated using Agrobacterium-mediated transformation. They were used to study the effect of altering the expression of this miRNA on time of flowering and to identify its mRNA target. Early or late flowering was observed in transgenic plants in which miR172 was overexpressed or suppressed, respectively. A full-length complementary DNA(cDNA) of gloxinia(Sinningia speciosa) APETALA2-like(SsAP2-like) was identified as a target of miR172. The altered expression levels of miR172 caused up-or down-regulation of SsAP2-like during flower development, which affected the time of flowering. Quantitative real-time reverse transcription PCR analysis of different gloxinia tissues revealed that the accumulation of SsAP2-like was negatively correlated with the expression of miR172 a, whereas the expression pattern of miR172 a was negatively correlated with that of miR156 a. Our results suggest that transgenic manipulation of miR172 could be used as a universal strategy for regulating time of flowering in ornamental plants.展开更多
Soybean(Glycine max)responds to ambient light variation by undergoing multiform morphological alterations,influencing its yield potential and stability in the field.Phytochromes(PHYs)are plant-specific red(R)and far-r...Soybean(Glycine max)responds to ambient light variation by undergoing multiform morphological alterations,influencing its yield potential and stability in the field.Phytochromes(PHYs)are plant-specific red(R)and far-red(FR)light photoreceptors mediating photomorphogenesis and photoperiodic flowering.As an ancient tetraploid,soybean harbors four PHYA,two PHYB,and two PHYE paralogs.Except for GmPHYA2/E4 and GmPHYA3/E3,which have been identified as photoperiod-dependent flowering repressors,the functions of GmPHYs are still largely unclear.We generated a series of individual or combined mutations targeting the GmPHYA or GmPHYB genes using CRISPR/Cas9 technology.Phenotypic analysis revealed that GmPHYB1 mediates predominantly R-light induced photomorphogenesis,whereas GmPHYA2/E4 and GmPHYA3/E3,followed by GmPHYA1 and GmPHYB2,function redundantly and additively in mediating FR light responses in seedling stage.GmPHYA2/E4 and GmPHYA3/E3,with weak influence from GmPHYA1 and GmPHYA4,delay flowering time under natural long-day conditions.This study has demonstrated the diversified functions of GmPHYAs and GmPHYBs in regulating light response,and provides a core set of phytochrome mutant alleles for characterization of their functional mechanisms in regulating agronomic traits of soybean.展开更多
Flowering time is an important agronomic trait for soybean yield and adaptation. However, the genetic basis of soybean adaptation to diverse latitudes is still not clear. Four NIGHT LIGHT-INDUCIBLE AND CLOCK-REGULATED...Flowering time is an important agronomic trait for soybean yield and adaptation. However, the genetic basis of soybean adaptation to diverse latitudes is still not clear. Four NIGHT LIGHT-INDUCIBLE AND CLOCK-REGULATED 2(LNK2) homeologs of Arabidopsis thaliana LNK2 were identified in soybean. Three single-guide RNAs were designed for editing the four LNK2 genes. A transgene-free homozygous quadruple mutant of the LNK2 genes was developed using the CRISPR(clustered regularly interspaced short palindromic repeats)/Cas9(CRISPR-associated protein 9). Under long-day(LD) conditions, the quadruple mutant flowered significantly earlier than the wild-type(WT). Quantitative real-time PCR(q RT-PCR)revealed that transcript levels of LNK2 were significantly lower in the quadruple mutant than in the WT under LD conditions. LNK2 promoted the expression of the legume-specific E1 gene and repressed the expression of FT2 a. Genetic markers were developed to identify LNK2 mutants for soybean breeding.These results indicate that CRISPR/Cas9-mediated targeted mutagenesis of four LNK2 genes shortens flowering time in soybean. Our findings identify novel components in flowering-time control in soybean and may be beneficial for further soybean breeding in high-latitude environments.展开更多
Flowering time is an indicator of adaptation in maize and a key trait for selection in breeding.The genetic basis of flowering time in maize,especially in response to plant density,remains unclear.The objective of thi...Flowering time is an indicator of adaptation in maize and a key trait for selection in breeding.The genetic basis of flowering time in maize,especially in response to plant density,remains unclear.The objective of this study was to identify maize quantitative trait loci(QTL)associated with flowering time-related traits that are stably expressed under several plant densities and show additive effects that vary with plant density.Three hundred recombinant inbred lines(RIL)derived from a cross between Ye 478 and Qi 319,together with their parents,were planted at three plant densities(90,000,120,000,and 150,000 plants ha^(-1))in four environments.The five traits investigated were days to tasseling(DTT),days to silking(DTS),days to pollen shed(DTP),interval between anthesis and silking(ASI),and interval between tasseling and anthesis(TAI).A high-resolution bin map was used for QTL mapping.In the RIL population,the DTT,DTS,and DTP values increased with plant density,whereas the ASI and TAI values showed negligible response to plant density.A total of 72 QTL were identified for flowering time-related traits,including 15 stably expressed across environments.Maize flowering time under different densities seems to be regulated by complex pathways rather than by several major genes or an independent pathway.The effects of some stable QTL,especially qDTT8-1 and qDTT10-4,varied with plant density.Fine mapping and cloning of these QTL will shed light on the mechanism of flowering time and assist in breeding earlymaturing maize inbred lines and hybrids.展开更多
Flowering time is a key agronomic trait that directly affect the adaptation and yield of soybean.After whole genome duplications,about 75%of genes being represented by multiple copies in soybean.There are four TERMINA...Flowering time is a key agronomic trait that directly affect the adaptation and yield of soybean.After whole genome duplications,about 75%of genes being represented by multiple copies in soybean.There are four TERMINAL FLOWER 1(TFL1)genes in soybean,and the TFL1b(Dt1)has been characterized as the determinant of stem growth habit.The function of other TFL1 homologs in soybean is still unclear.Here,we generated knockout mutants by CRISPR/Cas9 genome editing technology and found that the tfl1c/tfl1d double mutants flowered significantly earlier than wild-type plants.We investigated that TFL1c and TFL1d could physically interact with the b ZIP transcription factor FDc1 and bind to the promoter of APETALA1a(AP1a).RNA-seq and q RT-PCR analyses indicated that TFL1c and TFL1d repressed the expressions of the four AP1 homologs and delayed the flowering time in soybean.The two genes play important roles in the regulation of flowering time in soybean and mainly act as the flowering inhibitors under long-day conditions.Our results identify novel components in the flowering-time regulation network of soybean and will be invaluable for molecular breeding of improved soybean yield.展开更多
Flowering time,a key transition point from vegetative to reproductive growth,is regulated by an intrinsic complex of endogenous and exogenous signals including nutrient status.For hundreds of years,nitrogen has been w...Flowering time,a key transition point from vegetative to reproductive growth,is regulated by an intrinsic complex of endogenous and exogenous signals including nutrient status.For hundreds of years,nitrogen has been well known to modulate flowering time,but the molecular genetic basis on how plants adapt to ever-changing nitrogen availability remains not fully explored.Here we explore how Arabidopsis natural variation in flowering time responds to nitrate fluctuation.Upon nitrate availability change,we detect accession-and photoperiod-specific flowering responses,which also feature a accession-specific dependency on growth traits.The flowering time variation correlates well with the expression of floral integrators,SOC1 and FT,in an accession-specific manner.We find that gene expression variation of key hub genes in the photoperiod-circadian-clock(GI),aging(SPLs)and autonomous(FLC)pathways associates with the expression change of these integrators,hence flowering time variation.Our results thus shed light on the molecular genetic mechanisms on regulation of accession-and photoperiod-specific flowering time variation in response to nitrate availability.展开更多
Manipulation of flowering time to develop cultivars with desired maturity dates is fundamental in plant breeding.It is desirable to generate polyploid rapeseed(Brassica napus L.)germplasm with varying flowering time c...Manipulation of flowering time to develop cultivars with desired maturity dates is fundamental in plant breeding.It is desirable to generate polyploid rapeseed(Brassica napus L.)germplasm with varying flowering time controlled by a few genes.In the present study,Bna SVP,a rapeseed homolog of the Arabidopsis SVP(Short Vegetative Phase)gene,was characterized and a set of mutants was developed using a CRISPR/Cas9-based gene-editing tool.A single construct targeting multiple sites was successfully applied to precisely mutate four copies of Bna SVP.The induced mutations in these copies were stably transmitted to subsequent generations.Homozygous mutants with loss-of-function alleles and free transgenic elements were generated across the four Bna SVP homologs.All mutant T_(1)lines tested in two environments(summer and winter growing seasons)showed early-flowering phenotypes.The decrease in flowering time was correlated with the number of mutated Bna SVP alleles.The quadruple mutants showed the shortest flowering time,with a mean decrease of 40.6%–50.7%in length relative to the wild type under the two growth conditions.Our study demonstrates the quantitative involvement of Bna SVP copies in the regulation of flowering time and provides valuable resources for rapeseed breeding.展开更多
Flowering time and branching type are important agronomic traits related to the adaptability and yield of soybean. Molecular bases for major flowering time or maturity loci, E1 to E4, have been identified. However, mo...Flowering time and branching type are important agronomic traits related to the adaptability and yield of soybean. Molecular bases for major flowering time or maturity loci, E1 to E4, have been identified. However, more flowering time genes in cultivars with different genetic backgrounds are needed to be mapped and cloned for a better understanding of flowering time regulation in soybean. In this study, we developed a population of Japanese cultivar（Toyomusume）×Chinese cultivar（Suinong 10） to map novel quantitative trait locus（QTL） for flowering time and branch number. A genetic linkage map of a F_2 population was constructed using 1 306 polymorphic single nucleotide polymorphism（SNP） markers using Illumina Soy SNP8 ki Select Bead Chip containing 7 189（SNPs）. Two major QTLs at E1 and E9, and two minor QTLs at a novel locus, qFT2_1 and at E3 region were mapped. Using other sets of F_2 populations and their derived progenies, the existence of a novel QTL of qFT2_1 was verified. qBR6_1, the major QTL for branch number was mapped to the proximate to the E1 gene, inferring that E1 gene or neighboring genetic factor is significantly contributing to the branch number.展开更多
Roses are important horticultural plants with enormous diversity in flowers and flowering behavior.However,molecular regulation of flowering time variation in roses remains poorly characterized.Here,we report an expan...Roses are important horticultural plants with enormous diversity in flowers and flowering behavior.However,molecular regulation of flowering time variation in roses remains poorly characterized.Here,we report an expansion of the FAR1/FRS-like genes that correlates well with the switch to prostrate-toerect growth of shoots upon flowering in Rosa wichuraiana‘Basye's Thornless'(BT).With the availability of the high-quality chromosome-level genome assembly for BT that we developed recently,we identified 91 RwFAR1/FRS-like genes,a significant expansion in contrast to 52 in Rosa chinensis‘Old Blush’(OB),a founder genotype in modern rose domestication.Rose FAR1/FRS-like proteins feature distinct variation in protein domain structures.The dispersed expansion of RwFAR1/FRS-like genes occurred specifically in clade I and II and is significantly associated with transposon insertion in BT.Most of the RwFAR1/FRS-like genes showed relatively higher expression level than their corresponding orthologs in OB.FAR1/FRS-like genes regulate light-signaling processes,shade avoidance,and flowering time in Arabidopsis thaliana.Therefore,the expansion and duplication of RwFAR1/FRS-like genes,followed by diversification in gene expression,might offer a novel leverage point for further understanding the molecular regulation of the variation in shoot-growth behavior and flowering time in roses.展开更多
The shoot apical meristem（SAM） continuously produces lateral organs in plants.Based on the identity of the lateral organs,the life cycle of a plant can be divided into two phases： vegetative and reproductive.The SA...The shoot apical meristem（SAM） continuously produces lateral organs in plants.Based on the identity of the lateral organs,the life cycle of a plant can be divided into two phases： vegetative and reproductive.The SAM produces leaves during the vegetative phase,whereas it gives rise to flowers in the reproductive phase（reviewed in Poethig,2003）.The floral transition,namely the switch from vegetative to reproductive growth,展开更多
Flowering time(FT) is a key maize domestication trait, variation in which allows maize to grow in a wide range of latitudes. Although previous studies have investigated the genetic control of FT-related traits per se,...Flowering time(FT) is a key maize domestication trait, variation in which allows maize to grow in a wide range of latitudes. Although previous studies have investigated the genetic control of FT-related traits per se, few studies of FT hybrid performance have been published. We characterized the genomic architecture associated with hybrid performance for FT in a hybrid panel by testcrossing Chang 7–2 with 328Ye478 × Qi319 recombinant inbred lines(RILs). We identified 11 quantitative trait loci(QTL) for hybrid performance in FT-related traits, including a major QTL qFH10 that controls hybrid performance and heterosis in a summer maize-growing region. However, this locus acts in regulating FT traits per se only in a spring maize-growing region. We validated ZmCCT10 as a candidate gene for qFH10 and found that differences between hybrids and their parental lines in DNA methylation in the differentially methylated region(DMR, –700 to –1520) of the ZmCCT10 promoter affected gene expression pattern and thereby FT in the summer maize-growing region.展开更多
Flowering time is critically important for crop yield, and detection of its genetic factors with strongly associated DNA markers is necessary in breeding programs. This study was undertaken to validate the quantitativ...Flowering time is critically important for crop yield, and detection of its genetic factors with strongly associated DNA markers is necessary in breeding programs. This study was undertaken to validate the quantitative trait loci （QTLs） underlying flowering time of sorghum based on the association between genotypes at SSR marker loci and flowering time in F3 family lines from self-pollinated heterozygous F2 plants developed by crossing between ＂SC112＂---an early flowering variety from Ethiopia and ＂Kikuchi Zairai＂--a late flowering variety from Japan. The results showed that the SSR markers linked to the QTLs on sorghum chromosomes 1, 2, 3, 5b, 7 and 8b were significantly （P 〈 0.05） associated with flowering time, and these markers and the QTLs reported previously are valid. On the other hand, the genotypes at the marker locus SB596 of qFT1-2 on chromosome 1 was not significantly associated with flowering time. The valid DNA markers, SB258 in qFTI-1, SB 1512 in qFT2, SB 1839 in qFT3, SB3369 in qFT5b, SB4096 in qFT7 and SB4540 and SB4660 in qFT8b, might be useful for DNA-marker assisted breeding.展开更多
Genotype-environment interaction(G×E)models have potential in digital breeding and crop phenotype pre-diction.Using genotype-specific parameters(GSPs)as a bridge,crop growth models can capture G×E and simula...Genotype-environment interaction(G×E)models have potential in digital breeding and crop phenotype pre-diction.Using genotype-specific parameters(GSPs)as a bridge,crop growth models can capture G×E and simulate plant growth and development processes.In this study,a dataset containing multi-environmental planting and flowering data for 169 genotypes,each with 700K single nucleotide polymorphism(SNP)markers was used.Three rice growth models(ORYZA,CERES-Rice,and RiceGrow),SNPs,and climatic indices were in-tegrated for flowering time prediction.Significant associations between GSPs and quantitative trait nucleotides(QTNs)were investigated using genome-wide association study(GWAS)methods.Several GSPs were associated with previously reported rice flowering genes,including DTH2,DTH3 and OsCOL15,demonstrating the genetic interpretability of the models.The rice models driven by SNPs-based GSPs showed a decrease in goodness of fit as reflected by increased root mean square errors(RMSE),compared to the traditional model calibration.The predictions of crop model were further modified using the machine learning(ML)methods and climate indicators.The accuracy of the modified predictions were comparable to what was achieved using the traditional calibration approach.In addition,the Multi-model ensemble(MME)was comparable to that of the best individual model.Implications of our findings can potentially facilitate molecular breeding and phenotypic prediction of rice.展开更多
In plants,numerous non-Mendelian inherited dominant effects,including over-,incomplete-,and codominance,are frequently observed,yet they remain insufficiently understood.A novel phenotype has been identified in specif...In plants,numerous non-Mendelian inherited dominant effects,including over-,incomplete-,and codominance,are frequently observed,yet they remain insufficiently understood.A novel phenotype has been identified in specific soybean transformants overexpressing a single 35S::GmFT2a copy:superearly flowering dominance is exclusively observed in hemizygotes,not in homozygotes.Homozygous individual exhibits si RNA-mediated DNA methylation,causing epigenetic transcriptional silencing,whereas no such effect occurs in hemizygotes.Intriguingly,two distinct rounds of DNA methylation establishment occur,each mediated by a different mechanism.The homozygotes that derived from the hemizygous mother plants carrying 35S::GmFT2a locus was associated with the initiation of CHHcontext DNA methylation at 35S promoters mediated by 21 and 22 nucleotide(nt)si RNAs.Subsequently,24 nt si RNAs contribute to additional CHG-and CG-context DNA methylation at 35S promoters during the homozygosity of genes in plants already homozygous in maternal lineage.Reducing DNA methylation levels can be achieved by generating a hemizygous genotype through a crossing experiment with a recessive genotype.This research has unveiled a phenomenon:hemizygote-dependent dominance resulting from transcriptional silencing in homozygote offsprings.It provides new insights into the molecular mechanism underlying dominant effects.展开更多
Flowering time(or heading date)is a crucial agronomic trait for the adaptation of rice to specific growing regions and seasons.Although many flowering time-related rice genes have been identified and functionally char...Flowering time(or heading date)is a crucial agronomic trait for the adaptation of rice to specific growing regions and seasons.Although many flowering time-related rice genes have been identified and functionally characterized,continuing in-depth research is revealing how transcription of these genes is regulated.In this study,we determined that a basic leucine zipper transcription factor(OsbZIP40)and its homologous protein(OsbZIP12)participate in the control of flowering time.Overexpression of OsbZIP40 delayed flowering.Double mutants in which both OsbZIP40 and OsbZIP12 were knocked out exhibited an early-flowering phenotype under both long-day and short-day conditions.However,there was no difference in the heading date between the wild-type and each single mutant.These results suggest that OsbZIP40 functions as a flowering suppressor.Both OsbZIP40 and OsbZIP12 bound directly to the Ehd1 promoter and repressed its expression.Furthermore,MOTHER OF FT AND TFL1(Os MFT1)interacted with OsbZIP40/OsbZIP12 and enhanced their repressive effects on Ehd1 expression.Based on the data,we present a transcriptional regulatory mechanism in which OsbZIP40 and OsbZIP12 interact with Os MFT1 and modulate Ehd1 expression to delay flowering.Our findings provide relevant insights into the molecular mechanisms regulating flowering time in rice.展开更多
基金supported by Yunnan Province Agricultural Joint Key Project(Grant No.202401BD070001-016)the National Natural Science Foundation of China(Grant No.32202530)+3 种基金Talent Introduction and Training Project of Yunnan Academy of Agricultural Sciences(Grant No.2024RCYP-09)Fundamental Research Project(Grant No.202401CF070046)Xingdian Talent support program(XDYC-QNRC-2023-0457)Yunnan Technology Innovation Center of Flower Technique.
文摘The proper flowering time of rose(Rosa hybrida)is vital for the market value of this horticultural crop,but the mechanism regulating this trait is largely unclear.Here,we found that the transcription factor SQUAMOSA PROMOTER BINDING PROTEIN-LIKE4(RhSPL4)positively regulates flowering time in rose.Transient silencing or overexpression transgenic rose plants of RhSPL4 exhibited delayed or early flowering,respectively.Analysis of transcriptome data from transgenic lines overexpressing RhSPL4 compared to the wild type indicated that differentially expressed genes were significantly enriched in the circadian rhythm pathway.Among the proteins encoded by these genes,RhSPL4 binds to the promoter of PSEUDO-RESPONSE REGULATOR 5-LIKE(RhPRR5L),as revealed in yeast one-hybrid,dual-Luciferase/Renilla luciferase reporter,chromatin immunoprecipitation-quantitative PCR and electrophoretic mobility shift assay.Furthermore,RhSPL4 specifically binds to the478 to441 bp region of the RhPRR5L promoter and activates its transcription.The silencing of RhPRR5L delayed flowering time in rose,resembling the phenotype of RhSPL4-silenced plants.Together,these results indicate that the RhSPL4-RhPRR5L module positively regulates flowering time in rose,laying the foundation for the genetic improvement of flowering time in this important horticultural crop.
基金supported by the National Key Research and Development Program of China(2022YFD1200400)the Scientific and Technological Innovation Team of Shaanxi Province(2024RSCXTD-69)+1 种基金the Key Research and Development Program of Shaanxi Province(2021LLRH-07)a grant from the Yang Ling Seed Industry Innovation Center(K3031122024).
文摘Appropriate flowering time in rapeseed(Brassica napus L.)is vital for preventing losses from weather,diseases,and pests.However,the molecular basis of its regulation remains largely unknown.Here,a genome-wide association study identifies BnaC09.FUL,a MADS-box transcription factor,as a promising candidate gene regulating flowering time in B.napus.BnaC09.FUL expression increases sharply in B.napus shoot apices near bolting.BnaC09.FUL overexpression results in early flowering,while BnaFUL mutation causes delayed flowering in B.napus.A zinc finger transcription factor,BnaC06.WIP2,is identified as an interaction partner of BnaC09.FUL,and BnaC06.WIP2 overexpression delays flowering in B.napus,with RNA sequencing revealing its influence on the expression of many flowering-associated genes.We further demonstrate that BnaC06.WIP2 directly represses the expression of BnaA05.SOC1,BnaC03.SOC1,BnaC04.SOC1,BnaC06.FT,BnaA06.LFY,BnaC07.FUL,BnaA08.CAL,and BnaC03.CAL and indirectly inhibits the expression of other flowering time-related genes.Genetic and molecular investigations highlight the antagonistic relationship between BnaC09.FUL and BnaC06.WIP2 in regulating the flowering time in B.napus through direct regulation of the expression of BnaC03.SOC1,BnaA08.CAL,and BnaC03.CAL.Overall,our findings provide a mechanism by which the BnaC09.FUL–BnaC06.WIP2 transcriptional regulatory module controls the flowering time in B.napus.
基金supported by National Natural Science Foundation of China(Grant Nos.32372733,32172594)Natural Science Foundation of Hebei(Grant No.C2020204111)+2 种基金S&T Program of Hebei(Grant No.21326344D)State Key Laboratory of North China Crop Improvement and Regulation(Grant No.NCCIR2023ZZ-1)the Starting Grant from Hebei Agricultural University(Grant No.YJ201920).
文摘Properly regulated flowering time is pivotal for successful plant reproduction.The floral transition from vegetative growth to reproductive growth is regulated by a complex gene regulatory network that integrates environmental signals and internal conditions to ensure that flowering takes place under favorable conditions.Brassica rapa is a diploid Cruciferae species that includes several varieties that are cultivated as vegetable or oil crops.Flowering time is one of the most important agricultural traits of B.rapa crops because of its influence on yield and quality.The transition to flowering in B.rapa is regulated by several environmental and developmental cues,which are perceived by several signaling pathways,including the vernalization pathway,the autonomous pathway,the circadian clock,the thermosensory pathway,and gibberellin(GA)signaling.These signals are integrated to control the expression of floral integrators BrFTs and BrSOC1s to regulate flowering.In this review,we summarized current research advances on the molecular mechanisms that govern flowering time regulation in B.rapa and compare this to what is known in Arabidopsis.
基金supported by the National Natural Science Foundation of China(U22A20473)the National Key Research and Development Program of China(2021YFD1201600)+2 种基金the China Agriculture Research System(CARS-04-PS01)the Agricultural Science and Technology Innovation Program(ASTIP)of Chinese Academy of Agricultural Sciences,Scientific Innovation 2030 Project(2022ZD0401703)the Platform of National Crop Germplasm Resources of China。
文摘Flowering time is important for adaptation of soybean(Glycine max)to different environments.Here,we conducted a genome-wide association study of flowering time using a panel of 1490 cultivated soybean accessions.We identified three strong signals at the qFT02-2 locus(Chr02:12037319–12238569),which were associated with flowering time in three environments:Gongzhuling,Mengcheng,and Nanchang.By analyzing linkage disequilibrium,gene expression patterns,gene annotation,and the diversity of variants,we identified an AP1 homolog as the candidate gene for the qFT02-2 locus,which we named GmAP1d.Only one nonsynonymous polymorphism existed among 1490 soybean accessions at position Chr02:12087053.Accessions carrying the Chr02:12087053-T allele flowered significantly earlier than those carrying the Chr02:12087053-A allele.Thus,we developed a cleaved amplified polymorphic sequence(CAPS)marker for the SNP at Chr02:12087053,which is suitable for marker-assisted breeding of flowering time.Knockout of GmAP1d in the‘Williams 82’background by gene editing promoted flowering under long-day conditions,confirming that GmAP1d is the causal gene for qFT02-2.An analysis of the region surrounding GmAP1d revealed that GmAP1d was artificially selected during the genetic improvement of soybean.Through stepwise selection,the proportion of modern cultivars carrying the Chr02:12087053-T allele has increased,and this allele has become nearly fixed(95%)in northern China.These findings provide a theoretical basis for better understanding the molecular regulatory mechanism of flowering time in soybean and a target gene that can be used for breeding modern soybean cultivars adapted to different latitudes.
基金supported by the National Key Research and Development Program of China(2023YFD1200600 to Xiaoya Lin)National Natural Science Foundation of China(32090060 to Fanjiang Kong,32001568 to Xiaoya Lin,31930083 to Baohui Liu,and 31901500 to Tiantian Bu)China Postdoctoral Science Foundation(2019 M652839 to Liyu Chen)。
文摘Soybean(Glycine max)is a short-day crop whose flowering time is regulated by photoperiod.The longjuvenile trait extends its vegetative phase and increases yield under short-day conditions.Natural variation in J,the major locus controlling this trait,modulates flowering time.We report that the three J-family genes influence soybean flowering time,with the triple mutant Guangzhou Mammoth-2 flowering late under short days by inhibiting transcription of E1-family genes.J-family genes offer promising allelic combinations for breeding.
基金Project supported by the National Natural Science Foundation of China(Nos.31171615 and 31401913)
文摘We investigated the microRNA172(miR172)-mediated regulatory network for the perception of changes in external and endogenous signals to identify a universally applicable floral regulation system in ornamental plants, manipulation of which could be economically beneficial. Transgenic gloxinia plants, in which miR172 was either overexpressed or suppressed, were generated using Agrobacterium-mediated transformation. They were used to study the effect of altering the expression of this miRNA on time of flowering and to identify its mRNA target. Early or late flowering was observed in transgenic plants in which miR172 was overexpressed or suppressed, respectively. A full-length complementary DNA(cDNA) of gloxinia(Sinningia speciosa) APETALA2-like(SsAP2-like) was identified as a target of miR172. The altered expression levels of miR172 caused up-or down-regulation of SsAP2-like during flower development, which affected the time of flowering. Quantitative real-time reverse transcription PCR analysis of different gloxinia tissues revealed that the accumulation of SsAP2-like was negatively correlated with the expression of miR172 a, whereas the expression pattern of miR172 a was negatively correlated with that of miR156 a. Our results suggest that transgenic manipulation of miR172 could be used as a universal strategy for regulating time of flowering in ornamental plants.
基金supported by the National Natural Science Foundation of China(31871705,32072091)the Agricultural Science and Technology Innovation Program(ASTIP)of the Chinese Academy of Agricultural Sciencesthe Central Public-interest Scientific Institution Basal Research Fund。
文摘Soybean(Glycine max)responds to ambient light variation by undergoing multiform morphological alterations,influencing its yield potential and stability in the field.Phytochromes(PHYs)are plant-specific red(R)and far-red(FR)light photoreceptors mediating photomorphogenesis and photoperiodic flowering.As an ancient tetraploid,soybean harbors four PHYA,two PHYB,and two PHYE paralogs.Except for GmPHYA2/E4 and GmPHYA3/E3,which have been identified as photoperiod-dependent flowering repressors,the functions of GmPHYs are still largely unclear.We generated a series of individual or combined mutations targeting the GmPHYA or GmPHYB genes using CRISPR/Cas9 technology.Phenotypic analysis revealed that GmPHYB1 mediates predominantly R-light induced photomorphogenesis,whereas GmPHYA2/E4 and GmPHYA3/E3,followed by GmPHYA1 and GmPHYB2,function redundantly and additively in mediating FR light responses in seedling stage.GmPHYA2/E4 and GmPHYA3/E3,with weak influence from GmPHYA1 and GmPHYA4,delay flowering time under natural long-day conditions.This study has demonstrated the diversified functions of GmPHYAs and GmPHYBs in regulating light response,and provides a core set of phytochrome mutant alleles for characterization of their functional mechanisms in regulating agronomic traits of soybean.
基金supported by National Key Research and Development Program of China(2017YFD0101305)the National Natural Science Foundation of China(31930083,31901568,31801384,31725021,and 31771815)。
文摘Flowering time is an important agronomic trait for soybean yield and adaptation. However, the genetic basis of soybean adaptation to diverse latitudes is still not clear. Four NIGHT LIGHT-INDUCIBLE AND CLOCK-REGULATED 2(LNK2) homeologs of Arabidopsis thaliana LNK2 were identified in soybean. Three single-guide RNAs were designed for editing the four LNK2 genes. A transgene-free homozygous quadruple mutant of the LNK2 genes was developed using the CRISPR(clustered regularly interspaced short palindromic repeats)/Cas9(CRISPR-associated protein 9). Under long-day(LD) conditions, the quadruple mutant flowered significantly earlier than the wild-type(WT). Quantitative real-time PCR(q RT-PCR)revealed that transcript levels of LNK2 were significantly lower in the quadruple mutant than in the WT under LD conditions. LNK2 promoted the expression of the legume-specific E1 gene and repressed the expression of FT2 a. Genetic markers were developed to identify LNK2 mutants for soybean breeding.These results indicate that CRISPR/Cas9-mediated targeted mutagenesis of four LNK2 genes shortens flowering time in soybean. Our findings identify novel components in flowering-time control in soybean and may be beneficial for further soybean breeding in high-latitude environments.
基金This study was supported by Hebei Province Special Postdoctoral Financial Assistance(B2017003030)the Youth Innovation Fund of the Institute of Cereal and Oil Crops,Hebei Academy of Agriculture and Forestry Sciences(LYS2017001)the Hebei Financial Special Project:Construction of Talents Team for Agricultural Science Technical Innovation,and the China Agriculture Research System(CARS-02).
文摘Flowering time is an indicator of adaptation in maize and a key trait for selection in breeding.The genetic basis of flowering time in maize,especially in response to plant density,remains unclear.The objective of this study was to identify maize quantitative trait loci(QTL)associated with flowering time-related traits that are stably expressed under several plant densities and show additive effects that vary with plant density.Three hundred recombinant inbred lines(RIL)derived from a cross between Ye 478 and Qi 319,together with their parents,were planted at three plant densities(90,000,120,000,and 150,000 plants ha^(-1))in four environments.The five traits investigated were days to tasseling(DTT),days to silking(DTS),days to pollen shed(DTP),interval between anthesis and silking(ASI),and interval between tasseling and anthesis(TAI).A high-resolution bin map was used for QTL mapping.In the RIL population,the DTT,DTS,and DTP values increased with plant density,whereas the ASI and TAI values showed negligible response to plant density.A total of 72 QTL were identified for flowering time-related traits,including 15 stably expressed across environments.Maize flowering time under different densities seems to be regulated by complex pathways rather than by several major genes or an independent pathway.The effects of some stable QTL,especially qDTT8-1 and qDTT10-4,varied with plant density.Fine mapping and cloning of these QTL will shed light on the mechanism of flowering time and assist in breeding earlymaturing maize inbred lines and hybrids.
基金supported by the National Natural Science Foundation of China(32022062,32001503)the Science and Technology Innovation Team of Soybean Modern Seed Industry in Hebei(21326313D)。
文摘Flowering time is a key agronomic trait that directly affect the adaptation and yield of soybean.After whole genome duplications,about 75%of genes being represented by multiple copies in soybean.There are four TERMINAL FLOWER 1(TFL1)genes in soybean,and the TFL1b(Dt1)has been characterized as the determinant of stem growth habit.The function of other TFL1 homologs in soybean is still unclear.Here,we generated knockout mutants by CRISPR/Cas9 genome editing technology and found that the tfl1c/tfl1d double mutants flowered significantly earlier than wild-type plants.We investigated that TFL1c and TFL1d could physically interact with the b ZIP transcription factor FDc1 and bind to the promoter of APETALA1a(AP1a).RNA-seq and q RT-PCR analyses indicated that TFL1c and TFL1d repressed the expressions of the four AP1 homologs and delayed the flowering time in soybean.The two genes play important roles in the regulation of flowering time in soybean and mainly act as the flowering inhibitors under long-day conditions.Our results identify novel components in the flowering-time regulation network of soybean and will be invaluable for molecular breeding of improved soybean yield.
基金supported by grants from National Natural Science Foundation of China(31570311 to J-Y H and 31800261 to F C)from the CAS Pioneer Hundred Talents Program(292015312D11035 to J-Y H)+2 种基金CAS Key Laboratory for Plant Diversity and Biogeography of East Asia to J-Y Hfrom the Postdoctoral targeted funding from Yunnan Provincethe Yunnan basic and applied research funding to F C。
文摘Flowering time,a key transition point from vegetative to reproductive growth,is regulated by an intrinsic complex of endogenous and exogenous signals including nutrient status.For hundreds of years,nitrogen has been well known to modulate flowering time,but the molecular genetic basis on how plants adapt to ever-changing nitrogen availability remains not fully explored.Here we explore how Arabidopsis natural variation in flowering time responds to nitrate fluctuation.Upon nitrate availability change,we detect accession-and photoperiod-specific flowering responses,which also feature a accession-specific dependency on growth traits.The flowering time variation correlates well with the expression of floral integrators,SOC1 and FT,in an accession-specific manner.We find that gene expression variation of key hub genes in the photoperiod-circadian-clock(GI),aging(SPLs)and autonomous(FLC)pathways associates with the expression change of these integrators,hence flowering time variation.Our results thus shed light on the molecular genetic mechanisms on regulation of accession-and photoperiod-specific flowering time variation in response to nitrate availability.
基金supported by the National Key Research and Development Program of China(2017YFE0104800)the National Natural Science Foundation of China(31671725)。
文摘Manipulation of flowering time to develop cultivars with desired maturity dates is fundamental in plant breeding.It is desirable to generate polyploid rapeseed(Brassica napus L.)germplasm with varying flowering time controlled by a few genes.In the present study,Bna SVP,a rapeseed homolog of the Arabidopsis SVP(Short Vegetative Phase)gene,was characterized and a set of mutants was developed using a CRISPR/Cas9-based gene-editing tool.A single construct targeting multiple sites was successfully applied to precisely mutate four copies of Bna SVP.The induced mutations in these copies were stably transmitted to subsequent generations.Homozygous mutants with loss-of-function alleles and free transgenic elements were generated across the four Bna SVP homologs.All mutant T_(1)lines tested in two environments(summer and winter growing seasons)showed early-flowering phenotypes.The decrease in flowering time was correlated with the number of mutated Bna SVP alleles.The quadruple mutants showed the shortest flowering time,with a mean decrease of 40.6%–50.7%in length relative to the wild type under the two growth conditions.Our study demonstrates the quantitative involvement of Bna SVP copies in the regulation of flowering time and provides valuable resources for rapeseed breeding.
基金supported by the National Key Research and Development Program of China(2016YFD0100201 and 2016YFD0101902)the Knowledge Innovation Project of Chinese Academy of Sciences(XDA08010105)the National Natural Science Foundation of China(31471518 and 31301338)
文摘Flowering time and branching type are important agronomic traits related to the adaptability and yield of soybean. Molecular bases for major flowering time or maturity loci, E1 to E4, have been identified. However, more flowering time genes in cultivars with different genetic backgrounds are needed to be mapped and cloned for a better understanding of flowering time regulation in soybean. In this study, we developed a population of Japanese cultivar（Toyomusume）×Chinese cultivar（Suinong 10） to map novel quantitative trait locus（QTL） for flowering time and branch number. A genetic linkage map of a F_2 population was constructed using 1 306 polymorphic single nucleotide polymorphism（SNP） markers using Illumina Soy SNP8 ki Select Bead Chip containing 7 189（SNPs）. Two major QTLs at E1 and E9, and two minor QTLs at a novel locus, qFT2_1 and at E3 region were mapped. Using other sets of F_2 populations and their derived progenies, the existence of a novel QTL of qFT2_1 was verified. qBR6_1, the major QTL for branch number was mapped to the proximate to the E1 gene, inferring that E1 gene or neighboring genetic factor is significantly contributing to the branch number.
基金This work was funded by the Strategic Priority Research Program of the Chinese Academy of Sciences to J-Y H(XDB31000000)the CAS Pioneer Hundred Talents Program to J-Y H(292015312D11035)and Yunnan Recruitment Program of Experts in Science to J-Y H.
文摘Roses are important horticultural plants with enormous diversity in flowers and flowering behavior.However,molecular regulation of flowering time variation in roses remains poorly characterized.Here,we report an expansion of the FAR1/FRS-like genes that correlates well with the switch to prostrate-toerect growth of shoots upon flowering in Rosa wichuraiana‘Basye's Thornless'(BT).With the availability of the high-quality chromosome-level genome assembly for BT that we developed recently,we identified 91 RwFAR1/FRS-like genes,a significant expansion in contrast to 52 in Rosa chinensis‘Old Blush’(OB),a founder genotype in modern rose domestication.Rose FAR1/FRS-like proteins feature distinct variation in protein domain structures.The dispersed expansion of RwFAR1/FRS-like genes occurred specifically in clade I and II and is significantly associated with transposon insertion in BT.Most of the RwFAR1/FRS-like genes showed relatively higher expression level than their corresponding orthologs in OB.FAR1/FRS-like genes regulate light-signaling processes,shade avoidance,and flowering time in Arabidopsis thaliana.Therefore,the expansion and duplication of RwFAR1/FRS-like genes,followed by diversification in gene expression,might offer a novel leverage point for further understanding the molecular regulation of the variation in shoot-growth behavior and flowering time in roses.
基金supported by the grant from the National Natural Science Foundation of China(Nos.31222029 and 91217306)State Key Basic Research Program of China(No. 2013CB 127000)+2 种基金Shanghai Pujiang Program(No.12PJ 1409900)Recruitment Program of Global Expects(China)the initiation grant from NKLPMG(SIPPE,SIBS)
文摘The shoot apical meristem（SAM） continuously produces lateral organs in plants.Based on the identity of the lateral organs,the life cycle of a plant can be divided into two phases： vegetative and reproductive.The SAM produces leaves during the vegetative phase,whereas it gives rise to flowers in the reproductive phase（reviewed in Poethig,2003）.The floral transition,namely the switch from vegetative to reproductive growth,
基金jointly funded by the National Natural Science Foundation of China (31971963)Agricultural Science and Technology Innovation Program of CAAS。
文摘Flowering time(FT) is a key maize domestication trait, variation in which allows maize to grow in a wide range of latitudes. Although previous studies have investigated the genetic control of FT-related traits per se, few studies of FT hybrid performance have been published. We characterized the genomic architecture associated with hybrid performance for FT in a hybrid panel by testcrossing Chang 7–2 with 328Ye478 × Qi319 recombinant inbred lines(RILs). We identified 11 quantitative trait loci(QTL) for hybrid performance in FT-related traits, including a major QTL qFH10 that controls hybrid performance and heterosis in a summer maize-growing region. However, this locus acts in regulating FT traits per se only in a spring maize-growing region. We validated ZmCCT10 as a candidate gene for qFH10 and found that differences between hybrids and their parental lines in DNA methylation in the differentially methylated region(DMR, –700 to –1520) of the ZmCCT10 promoter affected gene expression pattern and thereby FT in the summer maize-growing region.
文摘Flowering time is critically important for crop yield, and detection of its genetic factors with strongly associated DNA markers is necessary in breeding programs. This study was undertaken to validate the quantitative trait loci （QTLs） underlying flowering time of sorghum based on the association between genotypes at SSR marker loci and flowering time in F3 family lines from self-pollinated heterozygous F2 plants developed by crossing between ＂SC112＂---an early flowering variety from Ethiopia and ＂Kikuchi Zairai＂--a late flowering variety from Japan. The results showed that the SSR markers linked to the QTLs on sorghum chromosomes 1, 2, 3, 5b, 7 and 8b were significantly （P 〈 0.05） associated with flowering time, and these markers and the QTLs reported previously are valid. On the other hand, the genotypes at the marker locus SB596 of qFT1-2 on chromosome 1 was not significantly associated with flowering time. The valid DNA markers, SB258 in qFTI-1, SB 1512 in qFT2, SB 1839 in qFT3, SB3369 in qFT5b, SB4096 in qFT7 and SB4540 and SB4660 in qFT8b, might be useful for DNA-marker assisted breeding.
基金supported by the National Key Research and Development Program of China(2022YFD2001001)the Jiangsu Independent Innovation Fund Project of Agricultural Science and Technology[CX(21)1006]+1 种基金the Jiangsu Collaborative Innovation Center for Modern Crop Production(JCICMCP)the 111 Project.
文摘Genotype-environment interaction(G×E)models have potential in digital breeding and crop phenotype pre-diction.Using genotype-specific parameters(GSPs)as a bridge,crop growth models can capture G×E and simulate plant growth and development processes.In this study,a dataset containing multi-environmental planting and flowering data for 169 genotypes,each with 700K single nucleotide polymorphism(SNP)markers was used.Three rice growth models(ORYZA,CERES-Rice,and RiceGrow),SNPs,and climatic indices were in-tegrated for flowering time prediction.Significant associations between GSPs and quantitative trait nucleotides(QTNs)were investigated using genome-wide association study(GWAS)methods.Several GSPs were associated with previously reported rice flowering genes,including DTH2,DTH3 and OsCOL15,demonstrating the genetic interpretability of the models.The rice models driven by SNPs-based GSPs showed a decrease in goodness of fit as reflected by increased root mean square errors(RMSE),compared to the traditional model calibration.The predictions of crop model were further modified using the machine learning(ML)methods and climate indicators.The accuracy of the modified predictions were comparable to what was achieved using the traditional calibration approach.In addition,the Multi-model ensemble(MME)was comparable to that of the best individual model.Implications of our findings can potentially facilitate molecular breeding and phenotypic prediction of rice.
基金supported by grants from the National Key Research and Development Program of China(2023YFD120300)the National Natural Science Foundation of China(32201869)the Earmarked Fund for China Agriculture Research System(CARS-04)。
文摘In plants,numerous non-Mendelian inherited dominant effects,including over-,incomplete-,and codominance,are frequently observed,yet they remain insufficiently understood.A novel phenotype has been identified in specific soybean transformants overexpressing a single 35S::GmFT2a copy:superearly flowering dominance is exclusively observed in hemizygotes,not in homozygotes.Homozygous individual exhibits si RNA-mediated DNA methylation,causing epigenetic transcriptional silencing,whereas no such effect occurs in hemizygotes.Intriguingly,two distinct rounds of DNA methylation establishment occur,each mediated by a different mechanism.The homozygotes that derived from the hemizygous mother plants carrying 35S::GmFT2a locus was associated with the initiation of CHHcontext DNA methylation at 35S promoters mediated by 21 and 22 nucleotide(nt)si RNAs.Subsequently,24 nt si RNAs contribute to additional CHG-and CG-context DNA methylation at 35S promoters during the homozygosity of genes in plants already homozygous in maternal lineage.Reducing DNA methylation levels can be achieved by generating a hemizygous genotype through a crossing experiment with a recessive genotype.This research has unveiled a phenomenon:hemizygote-dependent dominance resulting from transcriptional silencing in homozygote offsprings.It provides new insights into the molecular mechanism underlying dominant effects.
基金supported by the National Key Research and Development Program of China(2024YFE0103400)the Natural Science Foundation of Jiangsu Province(BK20230013)+3 种基金the National Natural Science Foundation of China(32100259)the Program of Jiangsu Province Government(JBGS[2021]001-1-2)the Program of Zhongshan Biological Breeding Laboratory(ZSBBLKY2023-01)the PAPD Program from Jiangsu Government。
文摘Flowering time(or heading date)is a crucial agronomic trait for the adaptation of rice to specific growing regions and seasons.Although many flowering time-related rice genes have been identified and functionally characterized,continuing in-depth research is revealing how transcription of these genes is regulated.In this study,we determined that a basic leucine zipper transcription factor(OsbZIP40)and its homologous protein(OsbZIP12)participate in the control of flowering time.Overexpression of OsbZIP40 delayed flowering.Double mutants in which both OsbZIP40 and OsbZIP12 were knocked out exhibited an early-flowering phenotype under both long-day and short-day conditions.However,there was no difference in the heading date between the wild-type and each single mutant.These results suggest that OsbZIP40 functions as a flowering suppressor.Both OsbZIP40 and OsbZIP12 bound directly to the Ehd1 promoter and repressed its expression.Furthermore,MOTHER OF FT AND TFL1(Os MFT1)interacted with OsbZIP40/OsbZIP12 and enhanced their repressive effects on Ehd1 expression.Based on the data,we present a transcriptional regulatory mechanism in which OsbZIP40 and OsbZIP12 interact with Os MFT1 and modulate Ehd1 expression to delay flowering.Our findings provide relevant insights into the molecular mechanisms regulating flowering time in rice.
