BOTRYTIS SUSCEPTIBLE1 INTERACTOR （BOI） and its three homologs （BOIs） are RING domain-containing proteins that repress flowering. Here, we investigated how BOIs repress flowering. Genetic analysis of the boiQ quadr...BOTRYTIS SUSCEPTIBLE1 INTERACTOR （BOI） and its three homologs （BOIs） are RING domain-containing proteins that repress flowering. Here, we investigated how BOIs repress flowering. Genetic analysis of the boiQ quadruple mutant indicates that BOIs repress flowering mainly through FLOWERING LOCUS T （FT）. BOIs repress the expression of FT by CONSTANS （CO）-dependent and -independent mechanisms： in the CO-dependent mechanism, BOIs bind to CO, inhibit the targeting of CO to the FT locus, and thus repress the expression of FT; in the CO-independent mechanism, BOIs target the FT locus via a mechanism that requires DELLAs but not CO. This dual repression of FT makes BOIs strong repressors of flowering in both CO-dependent and CO-independent pathways in Arabidopsis thaliana. Our finding that BOIs inhibit CO targeting further suggests that, in addition to modulating CO mRNA expression and CO protein stability, flowering regulation can also modulate the targeting of CO to FT.展开更多
Mutations in Phytochrome Interacting Factors （PIFs） induce a conversion of the endodermal amyloplasts necessary for gravity sensing to plastids with developed thylakoids accompanied by abnormal activation of photosy...Mutations in Phytochrome Interacting Factors （PIFs） induce a conversion of the endodermal amyloplasts necessary for gravity sensing to plastids with developed thylakoids accompanied by abnormal activation of photosynthetic genes in the dark. In this study, we investigated how PIFs regulate endodermal plastid development by performing comparative transcriptome analysis. We show that both endodermal expression of PIF1 and global expression of the PIF quartet induce transcriptional changes in genes enriched for nuclear-encoded photosynthetic genes such as LHCA and LHCB. Among the 94 shared differentially expressed genes identified from the comparative transcriptome analysis, only 14 genes are demonstrated to be direct targets of PIF1, and most photosynthetic genes are not. Using a co-expression analysis, we identified a direct target of PIF, whose expression pattern shows a strong negative correlation with many photo- synthetic genes. We have named this gene REPRESSOR OF PHOTOSYNTHETIC GENES1 （RPGE1）. Endodermal expression of RPGE1 rescued the elevated expression of photosynthetic genes found in the pff quadruple （pifQ） mutant and partly restored amyloplast development and hypocotyl negative gravitropism. Taken together, our results indicate that RPGE1 acts downstream of PIF1 in the endodermis to repress photosynthetic genes and regulate plastid development.展开更多
文摘BOTRYTIS SUSCEPTIBLE1 INTERACTOR （BOI） and its three homologs （BOIs） are RING domain-containing proteins that repress flowering. Here, we investigated how BOIs repress flowering. Genetic analysis of the boiQ quadruple mutant indicates that BOIs repress flowering mainly through FLOWERING LOCUS T （FT）. BOIs repress the expression of FT by CONSTANS （CO）-dependent and -independent mechanisms： in the CO-dependent mechanism, BOIs bind to CO, inhibit the targeting of CO to the FT locus, and thus repress the expression of FT; in the CO-independent mechanism, BOIs target the FT locus via a mechanism that requires DELLAs but not CO. This dual repression of FT makes BOIs strong repressors of flowering in both CO-dependent and CO-independent pathways in Arabidopsis thaliana. Our finding that BOIs inhibit CO targeting further suggests that, in addition to modulating CO mRNA expression and CO protein stability, flowering regulation can also modulate the targeting of CO to FT.
文摘Mutations in Phytochrome Interacting Factors （PIFs） induce a conversion of the endodermal amyloplasts necessary for gravity sensing to plastids with developed thylakoids accompanied by abnormal activation of photosynthetic genes in the dark. In this study, we investigated how PIFs regulate endodermal plastid development by performing comparative transcriptome analysis. We show that both endodermal expression of PIF1 and global expression of the PIF quartet induce transcriptional changes in genes enriched for nuclear-encoded photosynthetic genes such as LHCA and LHCB. Among the 94 shared differentially expressed genes identified from the comparative transcriptome analysis, only 14 genes are demonstrated to be direct targets of PIF1, and most photosynthetic genes are not. Using a co-expression analysis, we identified a direct target of PIF, whose expression pattern shows a strong negative correlation with many photo- synthetic genes. We have named this gene REPRESSOR OF PHOTOSYNTHETIC GENES1 （RPGE1）. Endodermal expression of RPGE1 rescued the elevated expression of photosynthetic genes found in the pff quadruple （pifQ） mutant and partly restored amyloplast development and hypocotyl negative gravitropism. Taken together, our results indicate that RPGE1 acts downstream of PIF1 in the endodermis to repress photosynthetic genes and regulate plastid development.
