Rice yield and heading date are two distinct traits controlled by quantitative trait loci （QTLs）. The dissection of molecular mechanisms underlying rice yield traits is important for developing high-yielding rice va...Rice yield and heading date are two distinct traits controlled by quantitative trait loci （QTLs）. The dissection of molecular mechanisms underlying rice yield traits is important for developing high-yielding rice varieties. Here, we report the cloning and characterization of Ghd8, a major QTL with pleiotropic effects on grain yield, heading date, and plant height. Two sets of near isogenic line populations were developed for the cloning of GhdS. Ghd8 was narrowed down to a 20-kb region containing two putative genes, of which one encodes the OsHAP3 subunit of a CCAAT-box binding protein （HAP complex）; this gene was regarded as the Ghd8 candidate. A complementary test confirmed the identity and pleiotropic effects of the gene; interestingly, the genetic effect of Ghd8 was dependent on its genetic background. By regulating Ehdl, RFT1, and Hd3a, Ghd8 delayed flowering under long-day conditions, but promoted flowering under short-day conditions. Ghd8 up-regulated MOC1, a key gene controlling tillering and branching; this increased the number of tillers, primary and secondary branches, thus producing 50% more grains per plant. The ectopic expression of Ghd8 in Arabidopsis caused early flowering by 10 d-a situation similar to the one observed by its homolog AtHAP3b, when compared to wild-type under long-day conditions; these findings indicate the conserved function of Ghd8 and AtHAP3b in flowering in Arabidopsis. Our results demonstrated the important roles of Ghd8 in rice yield formation and flowering, as well as its opposite functions in flowering between rice and Arabidopsis under long-day conditions.展开更多
In plant development, the flowering transition and inflorescence architecture are modulated by two homol- ogous proteins, FLOWERING LOCUS T （FT） and TERMINAL FLOWER 1 （TFL1）. The florigen FT promotes the transitio...In plant development, the flowering transition and inflorescence architecture are modulated by two homol- ogous proteins, FLOWERING LOCUS T （FT） and TERMINAL FLOWER 1 （TFL1）. The florigen FT promotes the transition to reproductive development and flowering, while TFL1 represses this transition. Despite their importance to plant adaptation and crop improvement and their extensive study by the plant community, the molecular mechanisms controlling the opposing actions of FT and TFL1 have remained mysterious. Recent studies in multiple species have unveiled diverse roles of the FT/TFL 1 gene family in developmental processes other than flowering regulation. In addition, the striking evolution of FT homologs into flowering repressors has occurred independently in several species during the evolution of flowering plants. These reports indicate that the FT/TFL1 gene family is a major target of evolution in nature. Here, we comprehen- sively survey the conserved and diverse functions of the FTITFL1 gene family throughout the plant kingdom, summarize new findings regarding the unique evolution of FT in multiple species, and highlight recent work elucidating the molecular mechanisms of these proteins.展开更多
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 pla...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.展开更多
文摘Rice yield and heading date are two distinct traits controlled by quantitative trait loci （QTLs）. The dissection of molecular mechanisms underlying rice yield traits is important for developing high-yielding rice varieties. Here, we report the cloning and characterization of Ghd8, a major QTL with pleiotropic effects on grain yield, heading date, and plant height. Two sets of near isogenic line populations were developed for the cloning of GhdS. Ghd8 was narrowed down to a 20-kb region containing two putative genes, of which one encodes the OsHAP3 subunit of a CCAAT-box binding protein （HAP complex）; this gene was regarded as the Ghd8 candidate. A complementary test confirmed the identity and pleiotropic effects of the gene; interestingly, the genetic effect of Ghd8 was dependent on its genetic background. By regulating Ehdl, RFT1, and Hd3a, Ghd8 delayed flowering under long-day conditions, but promoted flowering under short-day conditions. Ghd8 up-regulated MOC1, a key gene controlling tillering and branching; this increased the number of tillers, primary and secondary branches, thus producing 50% more grains per plant. The ectopic expression of Ghd8 in Arabidopsis caused early flowering by 10 d-a situation similar to the one observed by its homolog AtHAP3b, when compared to wild-type under long-day conditions; these findings indicate the conserved function of Ghd8 and AtHAP3b in flowering in Arabidopsis. Our results demonstrated the important roles of Ghd8 in rice yield formation and flowering, as well as its opposite functions in flowering between rice and Arabidopsis under long-day conditions.
文摘In plant development, the flowering transition and inflorescence architecture are modulated by two homol- ogous proteins, FLOWERING LOCUS T （FT） and TERMINAL FLOWER 1 （TFL1）. The florigen FT promotes the transition to reproductive development and flowering, while TFL1 represses this transition. Despite their importance to plant adaptation and crop improvement and their extensive study by the plant community, the molecular mechanisms controlling the opposing actions of FT and TFL1 have remained mysterious. Recent studies in multiple species have unveiled diverse roles of the FT/TFL 1 gene family in developmental processes other than flowering regulation. In addition, the striking evolution of FT homologs into flowering repressors has occurred independently in several species during the evolution of flowering plants. These reports indicate that the FT/TFL1 gene family is a major target of evolution in nature. Here, we comprehen- sively survey the conserved and diverse functions of the FTITFL1 gene family throughout the plant kingdom, summarize new findings regarding the unique evolution of FT in multiple species, and highlight recent work elucidating the molecular mechanisms of these proteins.
文摘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.
