PHOTOPERIODIC CONTROL OF HYPOCOTYL 1(PCH1)and PCH1-LIKE(PCHL)were shown to directly bind to phytochrome B(phyB)and suppress phyB thermal reversion,resulting in plants with dramatically enhanced light sensitivity.Here,...PHOTOPERIODIC CONTROL OF HYPOCOTYL 1(PCH1)and PCH1-LIKE(PCHL)were shown to directly bind to phytochrome B(phyB)and suppress phyB thermal reversion,resulting in plants with dramatically enhanced light sensitivity.Here,we show that PCH1 and PCHL also positively regulate various light responses,including seed germination,hypocotyl gravitropism,and chlorophyll biosynthesis,by physically interacting with PHYTOCHROME INTERACTING FACTOR 1(PIF1)and CONSTITUTIVE PHOTOMORPHO-GENIC 1(COP1).PCH1 and PCHL interact with PIF1 both in the dark and light,and regulate PIF1 abundance.Moreover,PCH1 and PCHL facilitate the physical interaction between phyB and PIF1 in vivo to promote the light-induced degradation of PIF1.PCH1 and PCHL also inhibit the DNA-binding ability of PIF1 to negatively regulate the expressions of PIF1 target genes.In addition,PCH1 and PCHL interact with COP1 and undergo degradation through the 26S proteasome pathway in the dark.Consistently,pch1 suppresses cop1 phenotype in darkness.Collectively,our study reveals a novel mechanism by which PCH1 and PCHL regulate diverse light responses not only by stabilizing phyB Pfrform but also by directly interacting with PIF1 and COP1,providing a molecular understanding of the control of hypocotyl growth by these proteins.展开更多
Baculoviruses produce two viral phenotypes, the budded virus （BV） and the occlusion-derived virus （ODV）. ODVs are released from occlusion bodies in the midgut where they initiate a primary infection. Due to the la...Baculoviruses produce two viral phenotypes, the budded virus （BV） and the occlusion-derived virus （ODV）. ODVs are released from occlusion bodies in the midgut where they initiate a primary infection. Due to the lack of an in vitro system, the molecular mechanism of ODV infection is still unclear. Here we present data demonstrating that Helicoverpa armigera nucleopolyhedrovirus （HearNPV） ODV infected cultured Hz-AM1 cells in a pH dependent manner. The optimal pH for ODV infection was 8.5, which is same to that in the microvilli of midgut epithelial cells, the ODV native infection sites. Antibodies neutralization analysis indicated that four HearNPV oral infection essential genes p74, pif-l, pif-2 and pif-3 are also essential for HearNPV ODV infection in vitro. Thus, HearNPV-HzAM1 system can be used to analyze the mechanism of ODV entry.展开更多
Leaf senescence can be triggered and promoted by a large number of developmental and environmental fac- tors. Numerous lines of evidence have suggested an involvement of phytochromes in the regulation of leaf senescen...Leaf senescence can be triggered and promoted by a large number of developmental and environmental fac- tors. Numerous lines of evidence have suggested an involvement of phytochromes in the regulation of leaf senescence, but the related signaling pathways and physiological mechanisms are poorly understood. In this study, we initially identi- fied phytochrome-interacting factors （PIFs） 3, 4, and 5 as putative mediators of leaf senescence. Mutations of the PIF genes resulted in a significantly enhanced leaf longevity in age-triggered and dark-induced senescence, whereas overexpressions of these genes accelerated age-triggered and dark-induced senescence in Arabidopsis. Consistently, loss-of-function of PIF4 attenuated dark-induced transcriptional changes associated with chloroplast deterioration and reactive oxygen species （ROS） generation. ChlP-PCR and DualoLuciferase assays demonstrated that PIF4 can activate chlorophyll degradation regulatory gene NYE1 and repress chloroplast activity maintainer gene GLK2 by binding to their promoter regions. Finally, dark-induced ethylene biosynthesis and ethylene-induced senescence were both dampened in pif4, suggesting the involvement of PIF4 in both ethylene biosynthesis and signaling pathway. Our study provides evidence that PIF3, 4, and 5 are novel positive senes- cence mediators and gains an insight into the mechanism of light signaling involved in the regulation of leaf senescence.展开更多
基金supported by grants from the National Institutes of Health(GM-114297)National Science Foundation(MCB-1543813)to E.H.and by a grant from the German Research Foundation(DFG)to A.H.(HI 1369/7-1)by the DFG under Germany’s Excellence Strategy(CIBSS-EXC-2189-Project ID 390939984).
文摘PHOTOPERIODIC CONTROL OF HYPOCOTYL 1(PCH1)and PCH1-LIKE(PCHL)were shown to directly bind to phytochrome B(phyB)and suppress phyB thermal reversion,resulting in plants with dramatically enhanced light sensitivity.Here,we show that PCH1 and PCHL also positively regulate various light responses,including seed germination,hypocotyl gravitropism,and chlorophyll biosynthesis,by physically interacting with PHYTOCHROME INTERACTING FACTOR 1(PIF1)and CONSTITUTIVE PHOTOMORPHO-GENIC 1(COP1).PCH1 and PCHL interact with PIF1 both in the dark and light,and regulate PIF1 abundance.Moreover,PCH1 and PCHL facilitate the physical interaction between phyB and PIF1 in vivo to promote the light-induced degradation of PIF1.PCH1 and PCHL also inhibit the DNA-binding ability of PIF1 to negatively regulate the expressions of PIF1 target genes.In addition,PCH1 and PCHL interact with COP1 and undergo degradation through the 26S proteasome pathway in the dark.Consistently,pch1 suppresses cop1 phenotype in darkness.Collectively,our study reveals a novel mechanism by which PCH1 and PCHL regulate diverse light responses not only by stabilizing phyB Pfrform but also by directly interacting with PIF1 and COP1,providing a molecular understanding of the control of hypocotyl growth by these proteins.
基金National Nature Science Foundations ofChina (30325002, 30470075)National Basic ResearchPriorities Program of China (2003CB1140).
文摘Baculoviruses produce two viral phenotypes, the budded virus （BV） and the occlusion-derived virus （ODV）. ODVs are released from occlusion bodies in the midgut where they initiate a primary infection. Due to the lack of an in vitro system, the molecular mechanism of ODV infection is still unclear. Here we present data demonstrating that Helicoverpa armigera nucleopolyhedrovirus （HearNPV） ODV infected cultured Hz-AM1 cells in a pH dependent manner. The optimal pH for ODV infection was 8.5, which is same to that in the microvilli of midgut epithelial cells, the ODV native infection sites. Antibodies neutralization analysis indicated that four HearNPV oral infection essential genes p74, pif-l, pif-2 and pif-3 are also essential for HearNPV ODV infection in vitro. Thus, HearNPV-HzAM1 system can be used to analyze the mechanism of ODV entry.
文摘Leaf senescence can be triggered and promoted by a large number of developmental and environmental fac- tors. Numerous lines of evidence have suggested an involvement of phytochromes in the regulation of leaf senescence, but the related signaling pathways and physiological mechanisms are poorly understood. In this study, we initially identi- fied phytochrome-interacting factors （PIFs） 3, 4, and 5 as putative mediators of leaf senescence. Mutations of the PIF genes resulted in a significantly enhanced leaf longevity in age-triggered and dark-induced senescence, whereas overexpressions of these genes accelerated age-triggered and dark-induced senescence in Arabidopsis. Consistently, loss-of-function of PIF4 attenuated dark-induced transcriptional changes associated with chloroplast deterioration and reactive oxygen species （ROS） generation. ChlP-PCR and DualoLuciferase assays demonstrated that PIF4 can activate chlorophyll degradation regulatory gene NYE1 and repress chloroplast activity maintainer gene GLK2 by binding to their promoter regions. Finally, dark-induced ethylene biosynthesis and ethylene-induced senescence were both dampened in pif4, suggesting the involvement of PIF4 in both ethylene biosynthesis and signaling pathway. Our study provides evidence that PIF3, 4, and 5 are novel positive senes- cence mediators and gains an insight into the mechanism of light signaling involved in the regulation of leaf senescence.
