Mapping and breeding value evaluation of a semi-dominant semidwarf gene in upland rice

Plant height is an important trait related to yield potential and plant architecture. A suitable plant height plays a crucial role in improvement of rice yield and lodging resistance. In this study, we found that the traditional upland landrace ＇Kaowenghan＇ （KWH） showed a special semi-dwarf phenotype. To identify the semi-dwarf gene from KWH, we raised BC2F4 semi-dwarf introgression lines （IL） by hybridization of the japonica rice cultivar ＇Dianjingyoul＇ （DJY1） and KWH in a DJY1 background. The plant height of the homozygous semi-dwarf IL （IL-87） was significantly reduced compared with that of DJY1. The phenotype of the F1 progeny of the semi-dwarf IL-87 and DJY1 showed that the semi-dwarf phenotype was semi- dominant. QTL mapping indicated that the semi-dwarf phenotype was controlled by a major QTL qDH1 and was localized between the markers RM6696 and RM12047 on chromosome 1. We also developed near-isogenic lines （NIL） from the BC3F3 population, and found that the yield of homozygous NIL （NIL-2） was not significantly different compared to DJY1. Breeding value evaluation through investigation of the plant height of the progeny of NIL （NIL-2） and cultivars from different genetic background indicate that the novel semi-dwarf gene shows potential as a genetic resource for rice breeding.

Phytochrome B regulates jasmonic acid-mediated defense response against Botrytis cinerea in Arabidopsis

The phytochrome B mediated light signaling integrates with various phytohormone signalings to control plant immune response.However,it is still unclear whether phyB-mediated light signaling has an effect on the biosynthesis of jasmonate during plant defense response against Botrytis cinerea.In this study,we demonstrated that phyB-mediated light signaling has a role in this process.Initially,we confirmed that phyb plants were obviously less resistant to B.cinerea while phyB overexpressing plants showed significantly enhanced resistance.We also found that the expression of numerous JA biosynthesis genes was promoted upon treatment with red or white light when compared to that of darkness,and that this promotion is dependent on phyB.Consistent with the gene expression results,phyb plants accumulated reduced pool of JA-lle,indicating that phyB-mediated light signaling indeed increased JA biosynthesis.Further genetic analysis showed that light-mediated JAZ9 degradation and phyB-enhanced resistance were dependent on the receptor COI1,and that pifl/3/4/5(pi/q)can largely rescue the severe symptom of phyb.Taken together,our study demonstrates that phyB may participate in plant defense against B.cinerea through the modulation of the biosynthesis of JA.

Functional characterization of the Arabidopsis SERRATE under salt stress

SERRATE(SE)plays critical roles in RNA metabolism and plant growth regulation.However,its function in stresseresponse processes remains largely unknown.Here,we examined the regulatory role of SE using the se-1 mutant and its complementation line under saline conditions.The expression of SE was repressed by salt treatment at both mRNA and protein levels.After treatment with different NaCl concentrations,the se-1 mutants showed increased sensitivity to salinity.This heightened sensitivity was evidenced by decreased germination,reduced root growth,more serious chlorosis,and increased conductivity of the mutants compared with the wild type.Further analysis revealed that SE regulates the pre-mRNA splicing of several well-characterized marker genes associated with salt stress tolerance.Our data thus imply that SE may function as a key component in plant response to salt stress by modulating the splicing of salt stress-associated genes.

AtWRKY75 positively regulates age-triggered leaf senescence through gibberellin pathway

WRKY transcription factors play essential roles during leaf senescence.However,the mechanisms by which they regulate this process remains largely unknown.Here,we identified the transcription factor WRKY75 as a positive regulator during leaf senescence.Mutations of WRKY75 caused a delay in agetriggered leaf senescence,whereas overexpression of WRKY75 markedly accelerated this process.Expression of senescence-associated genes(SAGs)was suppressed in WRKY75 mutants but increased in WRKY75-overexpressing plants.Further analysis demonstrated that WRKY75 directly associates with the promoters of SAG12 and SAG29,to activate their expression.Conversely,GAI and RGL1,two DELLA proteins,can suppress the WRKY75-mediated activation,thereby attenuating SAG expression during leaf senescence.Genetic analyses showed that GAI gain-of-function or RGL1 overexpression can partially rescue the accelerated senescence phenotype caused by WRKY75 overexpression.Furthermore,WRKY75 can positively regulate WRKY45 expression during leaf senescence.Our data thus imply that WRKY75 may positively modulate age-triggered leaf senescence through the gibberellin-mediated signaling pathway。

Identification and fine mapping of rtms1-D,a gene responsible for reverse thermosensitive genic male sterility from Diannong S-1X

Thermosensitive genic male sterility(TGMS)has been widely used in two-line hybrid rice breeding.Due to hybrid seed production being highly affected by changeable environments,its application scope is limited to some extent.Thus,it is of great importance to identify potential TGMS genes in specific rice varieties.Here,Diannong S-1 xuan(DNS-1 X),a reverse TGMS(RTGMS)japonica male sterile line,was identified from Diannong S-1.Genetic analysis showed that male sterility was tightly controlled by a single recessive gene,which was supported by the phenotype of the F;and F;populations derived from the cross between DNS-1 X and Yunjing 26(YJ26).Combining simple sequence repeat(SSR)markers and bulked segregation analysis(BSA),we identified a 215 kb region on chromosome 10 as a candidate reverse TGMS region,which was designated as rtmsl-D.It was narrower than the previously reported RTGMS genes rtmsl and tms6(t).The fertility conversion detected in the natural environment showed that DNS-1 X was sterile below 28-30℃;otherwise,it was fertile.Histological analysis further indicated that the pollen abortion was occurred in the young microspore stage.This study will provide new resources for two-line hybrid rice and pave the way for molecular breeding of RTGMS lines.

A hybrid sterile locus leads to the linkage drag of interspecific hybrid progenies

Interspecific hybridization plays an important role in rice breeding by broadening access to desirable traits such as disease resistance and improving yields.However,interspecific hybridization is often hindered by hybrid sterility,linkage drag,and distorted segregation.To mine for favorable genes from Oryza glaberrima,we cultivated a series of BC4 introgression lines(ILs)of O.glaberrima in the japonica rice variety background(Dianjingyou 1)in which the IL-2769(BC4F10)showed longer sterile lemmas,wider grains and spreading panicles compared with its receptor parent,suggesting that linkage drag may have occurred.Based on the BC5F2 population,a hybrid sterility locus,S20,a long sterile lemma locus,G1-g,and a new grain width quantitative trait locus(QTL),qGW7,were mapped in the linkage region about 15 centimorgan(cM)from the end of the short arm of chromosome 7.The hybrid sterility locus S20 from O.glaberrima eliminated male gametes of Oryza sativa,and male gametes carrying the alleles of O.sativa in the heterozygotes were aborted completely.In addition,the homozygotes presented a genotype of O.glaberrima,and homozygous O.sativa were not produced.Surprisingly,the linked traits G1-g and qGW7 showed similar segregation distortion.These results indicate that S20 was responsible for the linkage drag.As a large number of detected hybrid sterility loci are widely distributed on rice chromosomes,we suggest that hybrid sterility loci are the critical factors for the linkage drag in interspecific and subspecific hybridization of rice.

Transcription factor OsWRKY11 induces rice heading at low concentrations but inhibits rice heading at high concentrations

The heading date of rice is a crucial agronomic characteristic that influences its adaptability to different regions and its productivity potential.Despite the involvement of WRKY transcription factors in various biological processes related to development,the precise mechanisms through which these transcription factors regulate the heading date in rice have not been well elucidated.The present study identified OsWRKY11 as a WRKY transcription factor which exhibits a pivotal function in the regulation of the heading date in rice through a comprehensive screening of a clustered regularly interspaced palindromic repeats(CRISPR)-CRISPR-associated nuclease 9 mutant library that specifically targets the WRKY genes in rice.The heading date of oswrky11 mutant plants and OsWRKY11-overexpressing plants was delayed compared with that of the wild-type plants under short-day and long-day conditions.Mechanistic investigation revealed that OsWRKY11 exerts dual effects on transcriptional promotion and suppression through direct and indirect DNA binding,respectively.Under normal conditions,OsWRKY11 facilitates flowering by directly inducing the expression of OsMADS14 and OsMADS15.The presence of elevated levels of OsWRKY11 protein promote formation of a ternary protein complex involving OsWRKY11,Heading date 1(Hd1),and Days to heading date 8(DTH8),and this complex then suppresses the expression of Ehd1,which leads to a delay in the heading date.Subsequent investigation revealed that a mild drought condition resulted in a modest increase in OsWRKY11 expression,promoting heading.Conversely,under severe drought conditions,a significant upregulation of OsWRKY11 led to the suppression of Ehd1 expression,ultimately causing a delay in heading date.Our findings uncover a previously unacknowledged mechanism through which the transcription factor OsWRKY11 exerts a dual impact on the heading date by directly and indirectly binding to the promoters of target genes.

Multi-omics analysis reveals the evolutionary origin of diterpenoid alkaloid biosynthesis pathways in Aconitum

Diterpenoid alkaloids(DAs) have been often utilized in clinical practice due to their analgesic and anti-infammatory properties. Natural DAs are prevalent in the family Ranunculaceae, notably in the Aconitum genus. Nevertheless, the evolutionary origin of the biosynthesis pathway responsible for DA production remains unknown.In this study, we successfully assembled a highquality, pseudochromosome-level genome of the DA-rich species Aconitum vilmorinianum(A.vilmorinianum)(5.76 Gb). An A. vilmorinianumspecific whole-genome duplication event was discovered using comparative genomic analysis,which may aid in the evolution of the DA biosynthesis pathway. We identified several genes involved in DA biosynthesis via integrated genomic, transcriptomic, and metabolomic analyses. These genes included enzymes encoding target ent-kaurene oxidases and aminotransferases, which facilitated the activation of diterpenes and insertion of nitrogen atoms into diterpene skeletons, thereby mediating the transformation of diterpenes into DAs. The divergence periods of these genes in A. vilmorinianum were further assessed, and it was shown that two major types of genes were involved in the establishment of the DA biosynthesis pathway. Our integrated analysis offers fresh insights into the evolutionary origin of DAs in A.vilmorinianum as well as suggestions for engineering the biosynthetic pathways to obtain desired DAs.

Activated Expression of WRKY57 Confers Drought Tolerance in Arabidopsis

Drought is one of the most serious environmental factors that limit the productivity of agricultural crops worldwide. However, the mechanism underlying drought tolerance in plants is unclear. WRKY transcription factors are known to function in adaptation to abiotic stresses. By screening a pool of WRKY-associated T-DNA insertion mutants, we isolated a gain-of-function mutant, acquired drought tolerance （adt）, showing improved drought tolerance. Under drought stress conditions, adt accumulated higher levels of ABA than wild-type plants. Stomatal aperture analysis indi- cated that adt was more sensitive to ABA than wild-type plants. Molecular genetic analysis revealed that a T-DNA inser- tion in adt led to activated expression of a WRKY gene that encodes the WRKR57 protein. Constitutive expression of WRKY57 also conferred similar drought tolerance. Consistently with the high ABA content and enhanced drought tol- erance, three stress-responsive genes （RD29A, NCED3, and ABA3） were up-regulated in adt. ChIP assays demonstrated that WRKY57 can directly bind the W-box of RD29A and NCED3 promoter sequences. In addition, during ABA treatment, seed germination and early seedling growth of adt were inhibited, whereas, under high osmotic conditions, adt showed a higher seed germination frequency. In summary, our results suggested that the activated expression of WRKY57 improved drought tolerance of Arabidopsis by elevation of ABA levels. Establishment of the functions of WRKY57 will enable improvement of plant drought tolerance through gene manipulation approaches.

Arabidopsis WRKY Transcription Factors WRKY12 and WRKY13 Oppositely Regulate Flowering under Short-Day Conditions

In plants, photoperiod is an important cue for determining flowering. The floral transition in Arabidopsis thaliana is earlier under long-day （LD） than under short-day （SD） conditions. Flowering of Arabidopsis plants under SD conditions is mainly regulated by the plant hormone gibberellin （GA）. Here, we report two WRKY transcription factors function oppositely in controlling flowering time under SD conditions. Phenotypic analysis showed that disruption of WRKY12 caused a delay in flowering, while loss of WRKY13 function promoted flowering. WRKY12 and WRKY13 displayed negatively correlated expression profiles and function successively to regulate flowering. Molecular and genetic analyses demonstrated that FRUITFULL （FUL） is a direct downstream target gene of WRKY12 and WRKY13. Interestingly, we found that DELLA proteins GIBBERELLIN INSENSITIVE （GAI） and RGA-LIKE1 （RGL1） interacted with WRKY12 and WRKY13, and their interactions interfered with the transcriptional activity of the WRKY12 and WRKY13. Further studies suggested thatWRKY12 and WRKY13 partly mediated the effect of GA3 on controlling flowering time. Taken together, our results indicate that WRKY12 and WRKY13 oppositely modulate flower- ing time under SD conditions, which at least partially involves the action of GA.

Analysis of genetic architecture and favorable allele usage of agronomic traits in a large collection of Chinese rice accessions

Genotyping and phenotyping large natural populations provide opportunities for population genomic analysis and genome-wide association studies(GWAS). Several rice populations have been re-sequenced in the past decade;however, many major Chinese rice cultivars were not included in these studies. Here, we report large-scale genomic and phenotypic datasets for a collection mainly comprised of 1,275 rice accessions of widely planted cultivars and parental hybrid rice lines from China. The population was divided into three indica/Xian and three japonica/Geng phylogenetic subgroups that correlate strongly with their geographic or breeding origins. We acquired a total of 146 phenotypic datasets for 29 agronomic traits under multi-environments for different subpopulations. With GWAS, we identified a total of 143 significant association loci, including three newly identified candidate genes or alleles that control heading date or amylose content. Our genotypic analysis of agronomically important genes in the population revealed that many favorable alleles are underused in elite accessions, suggesting they may be used to provide improvements in future breeding efforts. Our study provides useful resources for rice genetics research and breeding.

The bHLH Transcription Factors MYC2, MYC3, and MYC4 Are Required for Jasmonate-Mediated Inhibition of Flowering in Arabidopsis

Dear Editor,In plants, the floral transition is flexibly controlled by various environmental conditions and endogenous developmental cues. In Arabidopsis, six major flowering pathways respond to changes in these factors （Fornara et al., 2010）. The photoperiod, vernalization, and ambient pathways monitor exogenous signals from the environment such as day length, minimum winter temperature, and ambient temperature （Fornara et al., 2010）. By contrast, the autonomous, gibberellin, and age pathways respond to endogenous cues linked to developmental status （Fornara et al., 2010）. Accumulating evidence indicates that the six flowering pathways converge in a network to regulate floral integrator genes FLOWERING LOCUS T （FT）, TWIN SISTER OF FT （TSF）, and SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1 （Fornara et al., 2010）.

Control of sulfate concentration by miR395-targeted APS genes in Arabidopsis thaliana

Sulfur nutrition is crucial for plant growth and development,as well as crop yield and quality.Inorganic sulfate in the soil is the major sulfur source for plants.After uptake,sulfate is activated by ATP sulfurylase,and then gets assimilated into sulfur-containing metabolites.However,the mechanism of regulation of sulfate levels by ATP sulfurylase is unclear.Here,we investigated the control of sulfate levels by miR395-mediated regulation of APS1/3/4.Sulfate was over-accumulated in the shoots of miR395 over-expression plants in which the expression of the APS1,APS3,and APS4 genes was suppressed.Accordingly,reduced expression of miR395 caused a decline of sulfate concentration.In agreement with these results,over-expression of the APS1,APS3,and APS4 genes led to the reduction of sulfate levels.Differential expression of these three APS genes in response to sulfate starvation implied that they have different functions.Further investigation revealed that the regulation of sulfate levels mediated by miR395 depends on the repression of its APS targets.Unlike the APS1,APS3,and APS4 genes,which encode plastid-localized ATP sulfurylases,the APS2 gene encodes a cytosolic version of ATP sulfurylase.Genetic analysis indicated that APS2 has no significant effect on sulfate levels.Our data suggest that miR395-targeted APS genes are key regulators of sulfate concentration in leaves.

WRKY transcription factors WRKY12 and WRKY13 interact with SPL10 to modulate age-mediated flowering

WRKY12 and WRKY13 are two WRKY transcription factors that play important roles in the control of flowering time under short-day(SD)conditions.The temporally regulated expression of WRKY12 and WRKY13 indicates that they may be involved in the age-mediated flowering pathway.However,their roles in this pathway are poorly understood.Here,we show that the transcription of WRKY12 and WRKY13 is directly regulated by SQUAMOSA PROMOTER BINDING-LIKE 10(SPLio),a transcription factor downstream of the age pathway.Binding and activation analyses revealed that SPL10 functions as a positive regulator of WRKY12 and a negative regulator of WRKY13.Further mechanistic investigation revealed that WRKY12 and WRKY13 physically interact with SPL10 and that both of them bind to the promoter of miRiy2b.Thus,the WRKY12-SPL10 and WRKY13-SPL10 interactions facilitate and inhibit SPL10 transcriptional function,respectively,to regulate miRiy2b expression.Together,our results show that WRKY12 and WRKY13 participate in the control of age-mediated flowering under SD conditions though physically interacting with SPLs and co-regulating the target gene miRi72b.

Trehalose phosphate synthase 5-dependent trehalose metabolism modulates basal defense responses in Arabidopsis thaliana

Despite the recent discovery that trehalose synthesis is important for plant development and abiotic stress tolerance, the effects of trehalose on biotic stress responses remain relatively unknown. In this study, we demonstrate that TREHALOSE PHOSPHATE SYNTHASE 5(TPS5)-dependent trehalose metabolism regulates Arabidopsis thaliana defenses against pathogens(necrotrophic Botrytis cinerea and biotrophic Pseudomonas syringae).Pathogen infection increased trehalose levels and upregulated TPS5 expression. Application of exogenous trehalose significantly improved plant defenses against B. cinerea, but increased the susceptibility of plants to P. syringae. We demonstrate that elevated trehalose biosynthesis, in transgenic plants over-expressing TPS5, also increased the susceptibility to P. syringae, but decreased the disease elcit r symptoms caused by B. cinerea. The knockout of TPS5 prevented the accumulation of trehalose and enhanced defense responses against P. syringae. Additionally, we observed that a TPS5-interacting protein(multiprotein bridging factor 1c) was required for induced expression of TPS5 during pathogen infections. Furthermore, we show that trehalose promotes P. syringae growth and disease development, via a mechanism involving suppression of the plant defense gene, Pathogenesis-Related Protein 1. These findings provide insight into the function of TPS5-dependent trehalose metabolism in plant basal defense responses.

Arabidopsis VQ10 interacts with WRKY8 to modulate basal defense against Botrytis cinerea

Recent studies in Arabidopsis have revealed that some vq motif-containing proteins physically interact with WRKY transcription factors; however, their specific biological functions are still poorly understood. In this study, we confirmed the interaction between VQ1o and WRKY8, and show that VQ1o and WRKY8 formed a complex in the plant cell nucleus. Yeast two-hybrid analysis showed that the middle region of WRKY8 and the vq motif of vqlo are critical for their interaction, and that this interaction promotes the DNA-binding activity of WRKY8. Further investigation revealed that the VqlO protein was exclusively localized in the nucleus, and VQ1o was predominantly expressed in siliques, vQ1o expression was strongly responsive to the necrotrophic fungal pathogen, Botrytis cinerea and defense-relatedhormones. Phenotypic analysis showed that disruption of VQlo increased mutant plants susceptibility to the fungal pathogen B. cinerea, whereas constitutive-expres- sion of VQlo enhanced resistance to B. cinerea. Consis- tent with these findings, expression of the defenserelated PLANT DEFENSIN1.2 （PDFt2） gene was decreased in vqlo mutant plants, after B. cinerea infection, but increased in vQ1o-overexpressing transgenic plants. Taken together, our findings provide evidence that VQlo physically interacts with WRKY8 and positively regulates plant basal resistance against the necrotrophic fungal pathogen B. cinerea.

ERF1 delays flowering through direct inhibition of FLOWERING LOCUS T expression in Arabidopsis

ETHYLENE RESPONSE FACTOR1(ERF1)is a key component in ethylene signaling,playing crucial roles in both biotic and abiotic stress responses.Here,we demonstrate that ERF1 also has an important role during floral initiation in Arabidopsis thaliana.Knockdown or knockout of ERF1 accelerated floral initiation,whereas overexpression of ERF1 dramatically delayed floral transition.These contrasting phenotypes were correlated with opposite transcript levels of FLOWERING LOCUS T(FT).Chromatin immunoprecipitation(ChIP)assays revealed that ERF1 associates with genomic regions of the FT gene to repress its transcription.ft-10/ERF1RNAi plants showed a similar flowering phenotype to the ft-10 mutant,whereas the flowering of FTox/ERF1ox mimicked that of FTox plants,suggesting that ERF1 acts upstream of FT during floral initiation.Similarly,altered floral transition in ethylene-related mutants was also correlated with FT expression.Further analysis suggested that ERF1 also participates in delay in flowering-time control mediated by the ethylene precursor 1-aminocyclopropane-1-carboxylic acid.Thus,ERF1 may act as a negative modulator of flowering-time control by repressing FT transcription in Arabidopsis.

Oryza sativa FER-LIKE FE DEFICIENCY-INDUCED TRANSCRIPTION FACTOR(OsFIT/OsbHLH156)interacts with OsIRO2 to regulate iron homeostasis

Iron(Fe)is indispensable for the growth and development of plants.It is well known that FER-LIKE FE DEFICIENCY-INDUCED TRANSCRIPTION FACTOR(FIT)is a key regulator of Fe uptake in Arabidopsis.Here,we identify the Oryza sativa FIT(also known as Osb HLH156)as the interacting partner of IRON-RELATED BHLH TRANSCRIPTION FACTOR 2(OsIRO2)that is critical for regulating Fe uptake.The OsIRO2 protein is localized in the cytoplasm and nucleus,but OsFIT facilitates the accumulation of OsIRO2 in the nucleus.Loss-of-function mutations of OsFIT result in decreased Fe accumulation,severe Fe-deficiency symptoms,and disrupted expression of Feuptake genes.In contrast,OsFIT overexpression promotes Fe accumulation and the expression of Fe-uptake genes.Genetic analyses indicate that OsFIT and OsIRO2 function in the same genetic node.Further analyses suggest that OsFIT and OsIRO2 form a functional transcription activation complex to initiate the expression of Fe-uptake genes.Our findings provide a mechanism understanding of how rice maintains Fe homeostasis.

bHLH104 confers tolerance to cadmium stress in Arabidopsis thaliana

Cd is a non-essential heavy metal that is toxic to both plants and animals. Here, we reveal that the transcription factor bHLH104 positively regulates Cd tolerance in Arabidopsis thaliana. We show that Fe deficiency-responsive genes were induced by Cd treat- ment, and that their upregulation was suppressed in bhlh104 loss-of-function mutants, but enhanced upon overexpression of bHLH104. Correspondingly, the bhlh104 mutants displayed sensitivity to Cd stress, whereas plants overexpressing bHLH104 exhibited enhanced Cd tolerance. Further analysis suggested that bHLH104 positivelyregulates four heavy metal detoxification-associated genes, IREG2, A4TP3, HA4A3 and NAS4, which play roles in Cd sequestration and tolerance. The bHLH104 overexpres- sion plants accumulated high levels of Cd in the root but low levels of Cd in the shoot, which might contribute to the Cd tolerance in those lines. The present study thus points to bHLH104 as a potentially useful tool for genetic engineering of plants with enhanced Cd tolerance.

Natural alleles of a uridine 5'-diphospho-glucosyltransferase gene responsible for differential endosperm development between upland rice and paddy rice

Traditional upland rice generally exhibits insufficient grains resulting from abnormal endosperm development compared to paddy rice. However, the underlying molecular mechanism of this trait is poorly understood. Here,we cloned the uridine 5’-diphospho(UDP)-glucosyltransferase gene EDR1(Endosperm Development in Rice) responsible for differential endosperm development between upland rice and paddy rice by performing quantitative trait loci analysis and map-based cloning. EDR1 was highly expressed in developing seeds duringgrain filling. Natural variations in EDR1 significantly reduced the UDP-glucosyltransferase activity of EDR1 YZNcompared to EDR1 YD1,resulting in abnormal endosperm development in the near-isogenic line, accompanied by insufficient grains and changes in grain quality.By analyzing the distribution of the two alleles EDR1 YD1 and EDR1 YZNamong diverse paddy rice and upland rice varieties, we discovered that EDR1 was conserved in upland rice, but segregated in paddy rice. Further analyses of grain chalkiness in the alleles of EDR1 YD1 and EDR1 YZNvarieties indicated that rice varieties harboring EDR1 YZNand EDR1 YD1 preferentially showed high chalkiness, and low chalkiness,respectively. Taken together, these results suggest that the UDP-glucosyltransferase gene EDR1 is an important determinant controlling differential endosperm development between upland rice and paddy rice.