Natural variation of GmFNSII-2 contributes to drought resistance by modulating enzyme activity in soybean

As an essential crop that provides vegetable oil and protein,soybean(Glycine max(L.)Merr.)is widely planted all over the world.However,the scarcity of water resources worldwide has seriously impacted on the quality and yield of soybean.To address this,exploring excellent genes for improving drought resistance in soybean is crucial.In this study,we identified natural variations of GmFNSII-2(flavone synthase II)significantly affect the drought resistance of soybeans.Through sequence analysis of GmFNSII-2 in 632 cultivated and 44 wild soybeans nine haplotypes were identified.The full-length allele GmFNSII-2^(C),but not the truncated allele GmFNSII-2^(A) possessing a nonsense nucleotide variation,increased enzyme activity.Further research found that GmDREB3,known to increase soybean drought resistance,bound to the promoter region of GmFNSII-2^(C).GmDREB3 positively regulated the expression of GmFNSII-2^(C),increased flavone synthase abundance and improved the drought resistance.Furthermore,a singlebase mutation in the GmFNSII-2^(C) promoter generated an additional drought response element(CCCCT),which had stronger interaction strength with GmDREB3 and increased its transcriptional activity under drought conditions.The frequency of drought-resistant soybean varieties with Hap 1(Pro:GmFNSII-2^(C))has increased,suggesting that this haplotype may be selected during soybean breeding.In summary,GmFNSII-2^(C) could be used for molecular breeding of drought-tolerant soybean.

Natural variation in the cytochrome c oxidase subunit 5B OsCOX5B regulates seed vigor by altering energy production in rice

Seed vigor is a crucial trait for the direct seeding of rice.Here we examined the genetic regulation of seed vigor traits in rice,including germination index(GI)and germination potential(GP),using a genome-wide association study approach.One major quantitative trait locus,qGI6/qGP6,was identified simultaneously for both GI and GP.The candidate gene encoding the cytochrome c oxidase subunit 5B(OsCOX5B)was validated for qGI6/qGP6.The disruption of OsCOX5B caused the vigor traits to be significantly lower in Oscox5b mutants than in the japonica Nipponbare wild type(WT).Gene co-expression analysis revealed that OsCOX5B influences seed vigor mainly by modulating the tricarboxylic acid cycle process.The glucose levels were significantly higher while the pyruvic acid and adenosine triphosphate levels were significantly lower in Oscox5b mutants than in WT during seed germination.The elite haplotype of OsCOX5B facilitates seed vigor by increasing its expression during seed germination.Thus,we propose that OsCOX5B is a potential target for the breeding of rice varieties with enhanced seed vigor for direct seeding.

Natural variation of main biochemical components,morphological and yield traits among a panel of 87 tea [Camellia sinensis(L.) O. Kuntze] cultivars

Many attentions have been previously focused to identify the multiple biochemical components related to tea quality and health benefits,however, the natural variation of biochemical components present in tea germplasm has not been adequately evaluated. In this study, the main biochemical components, leaf morphological and yield characteristics were evaluated for four rounds of tea leaves in a panel of 87 elite tea cultivars suitable for black, green, or oolong tea. Significant variations were observed among the tea cultivars, as well as seasonal differences in the levels of the free amino acid(FAA), caffeine(CAF), tea polyphenols(TP), water extract(WE) and TP to FAA ratio(TP/FAA). Results showed that the average levels of FAA showed a seasonal change, with the highest level of 4.0% in the 1st spring tea in the cultivars suitable for green tea and the lowest of 3.2% in summer tea in the cultivars suitable for black tea. The average CAF content was highest 3.2% in the cultivars suitable for oolong tea in the 1st spring and the lowest 2.5% in the cultivars suitable for green tea in summer. Limited seasonal and varietal variations were noticed in the average levels of WE among the three categories of tea. In addition, significant natural variation of the morphological characteristics, bud length varying from 2.5 cm to 8.7 cm, bud density from 190.3 buds · m-2to 1 730.3 buds · m-2, mature leaves biomass from 128.4 kg · hm-2to 2 888.4 kg · hm-2, and yield component traits of 100 buds(one bud with two leaves) dry weight from 3.7 g to37.7 g, tea yield/round from 444.6 kg · hm-2to 905.3 kg · hm-2, were observed. The aim of our evaluation was not only to identify the advantages of seasonal and clonal variations but also to provide a new viewpoint for their further application. Representative accessions were selected from the germplasm to promote the establishment of an inherent biochemical constituent expressing the quality of black, green, and oolong tea. The findings might be utilized to establish early selection criteria to enhance the tea breeding and production program.

OsNPF5.16, a nitrate transporter gene with natural variation, is essential for rice growth and yield

Rice has a large number of nitrate or peptide transporter family(NPF) genes, but the effects of most members on rice growth and development are unknown. We report that Os NPF5.16, a nitrate transporter gene with natural variation in its promoter sequence, is essential for rice growth and yield. The promoter sequence showed various differences between indica and japonica cultivars, and higher expression of Os NPF5.16 was found in indica cultivars with higher plant weight and more tillers than japonica cultivars.Os NPF5.16 was highly expressed in roots, tiller basal parts, and leaf sheaths, and its protein was localized on the plasma membrane. In c RNA-injected Xenopus laevis oocytes, Os NPF5.16 transport of nitrate at high nitrate concentration depended on p H. Overexpression of Os NPF5.16 increased nitrate content and total nitrogen content in leaf sheath as well as biomass and tiller bud length in rice. Elevated expression of Os NPF5.16 increased rice tiller number and grain yield by regulating cytokinin levels. Inhibition of Os NPF5.16 expression showed the opposite effects. Regulating Os NPF5.16 expression has potential for improving rice grain yield.

Natural Variation of Pto and Fen Genes and Marker-Assisted Selection for Resistance to Bacterial Speck in Tomato

The resistance in tomato plants to bacterial speck caused by Pseudomonas syringae pv. tomato is triggered by the interactions between the plant resistance protein Pto and the pathogen avirulence proteins AvrPto or AvrPtoB. Fen is a gene encoding closely related functional protein kinases as the Pto gene. To investigate the status of resistance to the pathogen and natural variation of Pto and Fen genes in tomato, 67 lines including 29 growing in China were subject to disease resistance evaluation and fenthion-sensitivity test. Alleles of Pto and Fen were amplified from genomic DNA of 25 tomato lines using polymerase chain reaction （PCR） and sequences were determined by sequencing the PCR products. The results indicated that none of the 29 cultivars/hybrids growing in China were resistant to bacterial speck race 0 strain DC3000. Seven of eight tomato lines resistant to DC3000 were also fenthion-sensitive. Analysis of deduced amino acid sequences identified three novel residue substitutions between Pto and pto, and one new substitution identified between Fen and fen. A PCR-based marker was developed and successfully used to select plants with resistance to DC3000.

Natural variation in MORE GRAINS 1 regulates grain number and grain weight in rice

Grain yield is determined mainly by grain number and grain weight.In this study,we identified and characterized MORE GRAINS1(MOG1),a gene associated with grain number and grain weight in rice(Oryza sativa L.),through map-based cloning.Overexpression of MOG1 increased grain yield by 18.6%-22.3%under field conditions.We determined that MOG1,a bHLH transcription factor,interacts with OsbHLH107 and directly activates the expression of LONELY GUY(LOG),which encodes a cytokinin-activating enzyme and the cell expansion gene EXPANSIN-LIKE1(EXPLA1),positively regulating grain number per panicle and grain weight.Natural variations in the promoter and coding regions of MOG1 between Hap-LNW and Hap-HNW alleles resulted in changes in MOG1 expression level and transcriptional activation,leading to functional differences.Haplotype analysis revealed that Hap-HNW,which results in a greater number and heavier grains,has undergone strong selection but has been poorly utilized in modern lowland rice breeding.In summary,the MOG1-OsbHLH107 complex activates LOG and EXPLA1 expression to promote cell expansion and division of young panicles through the cytokinin pathway,thereby increasing grain number and grain weight.These findings suggest that Hap-HNW could be used in strategies to breed high-yielding temperate japonica lowland rice.

Natural variations of maize ZmLecRK1 determine its interaction with ZmBAK1 and resistance patterns to multiple pathogens

Maize(Zea mays)is one of the most important crops in the world,but its yield and quality are seriously affected by diverse diseases.Identifying broad-spectrum resistance genes is crucial for developing effective strategies to control the disease in maize.In a genome-wide study in maize,we identified a G-type lectin receptor kinase ZmLecRK1,as a new resistance protein against Pythium aphanidermatum,one of the causal pathogens of stalk rot in maize.Genetic analysis showed that the specific ZmLecRK1 allele can confer resistance to multiple pathogens in maize.The cell death and disease resistance phenotype mediated by the resistant variant of ZmLecRK1 requires the co-receptor ZmBAK1.A naturally occurring A404S variant in the extracellular domain of ZmLecRK1 determines the ZmLecRK1-ZmBAK1 interaction and the formation of ZmLecRK1-related protein complexes.Interestingly,the ZmLecRK1 susceptible variant was found to possess the amino acid S404 that is present in the ancestral variants of ZmLecRK1 and conserved among the majority of grass species,while the resistance variant of ZmLecRK1 with A404 is only present in a few maize inbred lines.Substitution of S by A at position 404 in ZmLecRK1-like proteins of sorghum and rice greatly enhances their ability to induce cell death.Further transcriptomic analysis reveals that ZmLecRK1 likely regulates gene expression related to the pathways in cell wall organization or biogenesis in response to pathogen infection.Taken together,these results suggest that the ZmLecRK1 resistance variant enhances its binding affinity to the co-receptor ZmBAK1,thereby enhancing the formation of active complexes for defense in maize.Our work highlights the biotechnological potential for generating disease-resistant crops by precisely modulating the activity of ZmLecRK1 and its homologs through targeted base editing.

Natural variation of GmFATA1B regulates seed oil content and composition in soybean

Soybean(Glycine max) produces seeds that are rich in unsaturated fatty acids and is an important oilseed crop worldwide. Seed oil content and composition largely determine the economic value of soybean. Due to natural genetic variation, seed oil content varies substantially across soybean cultivars. Although much progress has been made in elucidating the genetic trajectory underlying fatty acid metabolism and oil biosynthesis in plants, the causal genes for many quantitative trait loci(QTLs) regulating seed oil content in soybean remain to be revealed. In this study, we identified Gm FATA1B as the gene underlying a QTL that regulates seed oil content and composition, as well as seed size in soybean. Nine extra amino acids in the conserved region of Gm FATA1B impair its function as a fatty acyl–acyl carrier protein thioesterase, thereby affecting seed oil content and composition. Heterogeneously overexpressing the functional Gm FATA1B allele in Arabidopsis thaliana increased both the total oil content and the oleic acid and linoleic acid contents of seeds. Our findings uncover a previously unknown locus underlying variation in seed oil content in soybean and lay the foundation for improving seed oil content and composition in soybean.

Natural variations of OsAUX5,a target gene of OsWRKY78,control the neutral essential amino acid content in rice grains

Grain essential amino acid(EAA)levels contribute to rice nutritional quality.However,the molecular mechanisms underlying EAA accumulation and natural variation in rice grains remain unclear.Here we report the identification of a previously unrecognized auxin influx carrier subfamily gene,OsAUX5,which encodes an amino acid transporter that functions in uptake of multiple amino acids.We identified an elite haplotype of Pro::OsAUX5^(Hap2) that enhances grain EAA accumulation without an apparent negative effect on agronomic traits.Natural variations of OsAUX5 occur in the cis elements of its promoter,which are differentially activated because of the different binding affinity between OsWRKY78 and the W-box,contributing to grain EAA variation among rice varieties.The two distinct haplotypes were shown to have originated from different Oryza rufipogon progenitors,which contributed to the divergence between japonica and indica.Introduction of the indica-type Pro::OsAUX5^(Hap2) genotype into japonica could significantly increase EAA levels,indicating that indica-type Pro::OsAUX5^(Hap2) can be utilized to increase grain EAAs of japonica varieties.Collectively,our study uncovers an WRKY78–OsAUX5-based regulatory mechanism controlling grain EAA accumulation and provides a potential target for breeding EAA-rich rice.

Natural Variation in OsPRR37 Regulates Heading Date and Contributes to Rice Cultivation at a Wide Range of Latitudes

Heading date and photoperiod sensitivity are fundamental traits that determine rice adaptation to a wide range of geographic environments. By quantitative trait locus （QTL） mapping and candidate gene analysis using whole- genome re-sequencing, we found that Oryza sativa Pseudo-Response Regulator37 （OsPRR37; hereafter PRR37） is respon- sible for the Early heading7-2 （EH7-2）/Heading date2 （Hd2） QTL which was identified from a cross of late-heading rice ＇Milyang23 （M23）＇ and early-heading rice ＇H143＇. H143 contains a missense mutation of an invariantly conserved amino acid in the CCT （CONSTANS, CO-like, and TOC1） domain of PRR37 protein. In the world rice collection, different types of nonfunctional PRR37 alleles were found in many European and Asian rice cultivars. Notably, the japonica varieties harboring nonfunctional alleles of both Ghd7/Hd4 and PRR37/Hd2 flower extremely early under natural long-day condi- tions, and are adapted to the northernmost regions of rice cultivation, up to 53~ N latitude. Genetic analysis revealed that the effects of PRR37 and Ghd7 alleles on heading date are additive, and PRR37 down-regulates Hd3a expression to suppress flowering under long-day conditions. Our results demonstrate that natural variations in PRR37/Hd2 and GhdT/ Hd4 have contributed to the expansion of rice cultivation to temperate and cooler regions.

Natural Variation in the Promoter of GSE5 Contributes to Grain Size Diversity in Rice

The utilization of natural genetic variation greatly contributes to improvement of important agronomic traits in crops. Understanding the genetic basis for natural variation of grain size can help breeders develop high- yield rice varieties. In this study, we identify a previously unrecognized gene, named GSE5, in the qSW5/ GW5 locus controlling rice grain size by combining the genome-wide association study with functional analyses. GSE5 encodes a plasma membrane-associated protein with ｜Q domains, which interacts with the rice calmodulin protein, OsCaMl-1. We found that loss of GSE5 function caused wide and heavy grains, while overexpression of GSE5 resulted in narrow grains. We showed that GSE5 regulates grain size predominantly by influencing cell proliferation in spikelet hulls. Three major haplotypes of GSE5 （GSE5, GSE5DELl＋IN1, and GSESDEL~ in cultivated rice were identified based on the deletion/insertion type in its pro- moter region. We demonstrated that a 950-bp deletion （DELl） in indica varieties carrying the GSE5DELl＋IN1 haplotype and a 1212-bp deletion （DEL2） in japonica varieties carrying the GSE5DEL2 haplotype associated with decreased expression of GSE5, resulting in wide grains. Further analyses indicate that wild rice acces- sions contain all three haplotypes of GSE5, suggesting that the GSE5 haplotypes present in cultivated rice are likely to have originated from different wild rice accessions during rice domestication. Taken together, our results indicate that the previously unrecognized GSE5 gene in the qSW5/GW5 locus, which is widely utilized by rice breeders, controls grain size, and reveal that natural variation in the promoter region of GSE5 contributes to grain size diversity in rice.

Comprehensive profiling and natural variation of flavonoids in rice

Flavonoids constitute a major group of plant phenolic compounds.While extensively studied in Arabidopsis,profiling and naturally occurring variation of these compounds in rice（Oryza sativa）,the monocot model plant,are less reported.Using a collection of rice germplasm,comprehensive profiling and natural variation of flavonoids were presented in this report.Application of a widely targeted metabolomics method facilitated the simultaneous identification and quantification of more than 90 flavonoids using liquid chromatography tandem mass spectrometry（LC-MS/MS）.Comparing flavonoid contents in various tissues during different developmental stages revealed tissue-specific accumulation of most flavonoids.Further investigation indicated that flavone mono-C-glycosides,malonylated flavonoid O-hexosides,and some flavonoid O-glycosides accumulated at significantly higher levels in indica than in japonica,while the opposite was observed for aromatic acylated flavone C-hexosyl-O-hexosides.In contrast to the highly differential accumulation between the two subspecies,relatively small variations within subspecies were detected for most flavonoids.Besides,an association analysis between flavonoid accumulation and its biosynthetic gene sequence polymorphisms disclosed that natural variation of flavonoids was probably caused by sequence polymorphisms in the coding region of flavonoid biosynthetic genes.Our work paves the way for future dissection of biosynthesis and regulation of flavonoid pathway in rice.

The divergence of brassinosteroid sensitivity between rice subspecies involves natural variation conferring altered internal auto-binding of OsBSK2

Japonica/geng and indica/xian are two major rice(Oryza sativa)subspecies with multiple divergent traits,but how these traits are related and interact within each subspecies remains elusive.Brassinosteroids(BRs)are a class of steroid phytohormones that modulate many important agronomic traits in rice.Here,using different physiological assays,we revealed that japonica rice exhibits an overall lower BR sensitivity than indica.Extensive screening of BR signaling genes led to the identification of a set of genes distributed throughout the primary BR signaling pathway with divergent polymorphisms.Among these,we demonstrate that the C38/T variant in BR Signaling Kinase2(OsBSK2),causing the amino acid change P13L,plays a central role in mediating differential BR signaling in japonica and indica rice.OsBSK2in indica plays a greater role in BR signaling than OsB SK2in japonica by affecting the auto-binding and protein accumulation of OsBSK2.Finally,we determined that OsBSK2 is involved in a number of divergent traits in japonica relative to indica rice,including grain shape,tiller number,cold adaptation,and nitrogen-use efficiency.Our study suggests that the natural variation in OsB SK2 plays a key role in the divergence of BR signaling,which underlies multiple divergent traits between japonica and indica.

Natural variation of H3K27me3 modification in two Arabidopsis accessions and their hybrid

Histone modifications affect gene expression, but the mechanism and biological consequence of natural variation in histone modifications remain unclear. Here, we generated genome-wide integrated maps of H3K27me3 modification and transcriptome for Col, C24 and their F1 hybrid. A total of 1,828 genomic regions showing variation in H3K27me3 modification between Col and C24 were identified, most of which were associated with genic regions. Natural variation of H3K27me3 modification between parents could result in aUelic bias of H3K27me3 in hybrids. Furthermore, we found that H3K27me3 variation between Col and C24 was negatively correlated with gene expression differences between two accessions, espe- cially with those arising from the cis-effect. Importantly, mutation of CLF, an Arabidopsis methyltransferase for H3K27,altered gene expression patterns between the parents. Together, these data provide insights into natural variation of histone modifications and their association with gene expression differences between Arabidopsis ecotypes.

Natural Variation in Tomato Reveals Differences in the Recognition of AvrPto and AvrPtoB Effectors from Pseudomonas syringae

The Pto protein kinase from Solanum pimpinellifolium interacts with Pseudomonas syringae effectors AvrPto or AvrPtoB to activate effector-triggered immunity. The previously solved crystal structures of the AvrPto-Pto and AvrPtoB-Pto complexes revealed that Pro binds each effector through both a shared and a unique interface. Hera we use natural variation in wild species of tomato to further investigate Pto recognition of these two effectors. One species, Solanum chmielewskU, was found to have many accessions that recognize only AvrPtoB. The Pto ortholog from one of these accessions was responsible for recognition of AvrPtoB and it differed from Solanum pimpinellifolium Pto by only 14 amino acids, including two in the AvrPto-specific interface, glutamate-49/glycine-51. Converting these two residues to those in Pro （histidine-49/valine-51） did not restore recognition of AvrPto. Subsequent experiments revealed that a single substitution of a histidine-to-aspartate at position 193 in Pto, which is not near the AvrPto- specific interface, was sufficient for conferring recognRion of AvrPto in plant cells. The reciprocal substi- tution of aspartate-to-histidine-193 in Pto abolished AvrPto recognition, confirming the importance of this residue. Our results reveal new aspects about effector recognition by Pto and demonstrate the value of using natural variation to understand the interaction between resistance proteins and pathogen effectors.

Natural variation in the transcription factor REPLUMLESS contributes to both disease resistance and plant growth in Arabidopsis

When attacked by pathogens,plants need to reallocate energy from growth to defense to fend off the invaders,frequently incurring growth penalties.This phenomenon is known as the growth–defense tradeoff and is orchestrated by a hardwired transcriptional network.Altering key factors involved in this network has the potential to increase disease resistance without growth or yield loss,but the mechanisms underlying such changes require further investigation.By conducting a genome-wide association study(GWAS)of leaves infected by the hemi-biotrophic bacterial pathogen Pseudomonas syringae pv.tomato(Pst)DC3000,we discovered that the Arabidopsis transcription factor REPLUMLESS(RPL)is necessary for bacterial resistance.More importantly,RPL functions in promoting both disease resistance and growth.Transcriptome analysis revealed a cluster of genes in the GRETCHEN HAGEN 3(GH3)family that were significantly upregulated in rpl mutants,leading to the accumulation of indole-3-acetic acid-aspartic acid(IAA-Asp).Consistent with this observation,transcripts of virulence effector genes were activated by IAA-Asp accumulated in the rpl mutants.We found that RPL protein could directly bind to GH3 promoters and repress their expression.RPL also repressed flavonol synthesis by directly repressing CHI expression and thus activated the auxin transport pathway,which promotes plant growth.Therefore,RPL plays an important role in plant immunity and functions in the auxin pathway to optimize Arabidopsis growth and defense.

Natural Variation in the Sequence of SNAC1 and Its Expression Level Polymorphism in Rice Germplasms under Drought Stress

Water is a major limiting factor for food production and many countries fail to produce sufficient food for their population due to severe water scarcity （Jury and Vaux, 2005）. Rice is the main staple food worldwide. More than 50% of rice in the world is rain-fed and drought causes severe reduction in rice grain yield in rain-fed environments （Venuprasad et al., 2007; Zhang, 2007; Sandhu et al., 2014）. Therefore, enhancing drought resistance （DR） of rice is important for food security. However, DR is a complex trait, which is controlled by a large number of loci with small effect and is also affected by different genetic background, genotype-by-environment interaction and other stresses such as heat （Hu and Xiong, 2014）.

Natural variation of hormone levels in Arabidopsis roots and correlations with complex root architecture

Studies on natural variation are an important tool to unravel the genetic basis of quantitative traits in plants. Despite the significant roles of phytohormones in plant development, including root architecture, hardly any studies have been done to investigate natural variation in endogenous hormone levels in plants. Therefore, in the present study a range of hormones were quantified in root extracts of thirteen Arabidopsis thaliana accessions using a ultra performance liquid chromatography triple quadrupole mass spectrometer. Root system architecture of the set of accessions was quantified, using a new parameter （mature root unit） for complex root systems, and correlated with the phytohormone data. Significant variations in phytohormone levels among the accessions were detected, but were remarkably small, namely less than three-fold difference between extremes. For cytokinins, relatively larger variations were found for ribosides and glucosides, as compared to the free bases. For root phenotyping, length-related traits--lateral root length and total root length--showed larger variations than lateral root number-related ones. For root architecture, antagonistic interactions between hormones, for example, indole-3-acetic acid to trans-zeatin were detected in correlation analysis. These findings provide conclusive evidence for the presence of natural variation in phytohormone levels in Arabidopsis roots, suggesting that quantitative genetic analyses are feasible.

Genetic variation in ZmSO contributes to ABA response and drought tolerance in maize seedlings

Water scarcity impairs maize growth and yield.Identification and deployment of superior droughttolerance alleles is desirable for the genetic improvement of stress tolerance in maize.Our previous study revealed that maize sulfite oxidase(SO) catalyzes the oxidation of sulfite to sulfate and may be involved in drought response.But it was unclear whether the natural variation in Zm SO is directly associated with the drought resistance of maize.In the present study,we showed that Zm SO was associated with drought tolerance in maize seedlings,using gene association analysis and a transgene approach.A 14-bp insertion variation,containing two ABA-responsive elements,in the promoter region of Zm SO conferred ABAinducible expression,leading to increased drought tolerance.Genetic selection of this favorable allele increased drought tolerance.This study has identified elite alleles associated with sulfur metabolism for improving maize drought resistance.

Accession-specific flowering time variation in response to nitrate fluctuation in Arabidopsis thaliana

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.