Seed dormancy of cultivated rice was largely weakened during the progress of domestication.Correct timing and uniformity of seed germination are important for rapid seedling establishment and highyield production.In t...Seed dormancy of cultivated rice was largely weakened during the progress of domestication.Correct timing and uniformity of seed germination are important for rapid seedling establishment and highyield production.In the present study,we found that the heading-date gene Ghd7 acted as a negative regulator of germination.A mutant of ghd7 showed low sensitivity to exogenous ABA treatment during seed germination.Further investigation revealed reduced accumulation of ABA in mature ghd7 seeds as a consequence of dampened expression of OsNCED genes.Moreover,elevated GA_(3) level was detected in seeds of ghd7 mutant during imbibition course,which was attributed to the induction of genes responsible for the synthesis pathways of bioactive GAs.Thus,Ghd7 inhibits seed germination by increasing the ABA/GA_(3) ratio.Besides revealing pleiotropic effects of Ghd7,our results indicate its role in linking seed germination to growth-phase transition in rice,which would enrich the theoretical basis for future breeding practices.展开更多
Ghd7 is an important gene involved in the photoperiod flowering pathway in rice.A Ghd7-involved transcriptional regulatory network has been established,but its translational regulatory pathway is poorly understood.The...Ghd7 is an important gene involved in the photoperiod flowering pathway in rice.A Ghd7-involved transcriptional regulatory network has been established,but its translational regulatory pathway is poorly understood.The mutant suppressor of overexpression of Ghd7(sog7)was identified from EMS-induced mutagenesis on the background of ZH11 overexpressing Ghd7.Mut Map analysis revealed that SOG7 is allelic to Ghd8 and delayed flowering under long-day(LD)conditions.Biochemical assays showed that Ghd8 interacts with OsHAP5C and Ghd7 both in vivo and in vitro.Surprisingly,a point mutation E96K in theα2 helix of the Ghd8 histone fold domain(HFD)destroyed its ability to interact with Ghd7.The prediction of the structure shows that mutated amino acid is located in the interaction region of CCT/NF-YB/YC complexes,which alter the structure ofα4 of Ghd8.This structural difference prevents the formation of complex NF-YB/YC.The triple complex of Ghd8-OsHAP5C-Ghd7 directly bound to the promotor of Hd3a and downregulated the expression of Ehd1,Hd3a and RFT1,and finally resulted in a delayed heading.These findings are helpful in deeply understanding the Ghd7-involved photoperiod flowering pathway and promote the elucidation of rice heading.展开更多
基金This work was supported by the National Key Research and Development Program of China(2017YFD0100406)China Postdoctoral Science Foundation(2019M652606).
文摘Seed dormancy of cultivated rice was largely weakened during the progress of domestication.Correct timing and uniformity of seed germination are important for rapid seedling establishment and highyield production.In the present study,we found that the heading-date gene Ghd7 acted as a negative regulator of germination.A mutant of ghd7 showed low sensitivity to exogenous ABA treatment during seed germination.Further investigation revealed reduced accumulation of ABA in mature ghd7 seeds as a consequence of dampened expression of OsNCED genes.Moreover,elevated GA_(3) level was detected in seeds of ghd7 mutant during imbibition course,which was attributed to the induction of genes responsible for the synthesis pathways of bioactive GAs.Thus,Ghd7 inhibits seed germination by increasing the ABA/GA_(3) ratio.Besides revealing pleiotropic effects of Ghd7,our results indicate its role in linking seed germination to growth-phase transition in rice,which would enrich the theoretical basis for future breeding practices.
基金supported by the Youth Foundation of China(31601283)。
文摘Ghd7 is an important gene involved in the photoperiod flowering pathway in rice.A Ghd7-involved transcriptional regulatory network has been established,but its translational regulatory pathway is poorly understood.The mutant suppressor of overexpression of Ghd7(sog7)was identified from EMS-induced mutagenesis on the background of ZH11 overexpressing Ghd7.Mut Map analysis revealed that SOG7 is allelic to Ghd8 and delayed flowering under long-day(LD)conditions.Biochemical assays showed that Ghd8 interacts with OsHAP5C and Ghd7 both in vivo and in vitro.Surprisingly,a point mutation E96K in theα2 helix of the Ghd8 histone fold domain(HFD)destroyed its ability to interact with Ghd7.The prediction of the structure shows that mutated amino acid is located in the interaction region of CCT/NF-YB/YC complexes,which alter the structure ofα4 of Ghd8.This structural difference prevents the formation of complex NF-YB/YC.The triple complex of Ghd8-OsHAP5C-Ghd7 directly bound to the promotor of Hd3a and downregulated the expression of Ehd1,Hd3a and RFT1,and finally resulted in a delayed heading.These findings are helpful in deeply understanding the Ghd7-involved photoperiod flowering pathway and promote the elucidation of rice heading.
