CONSTANS(CO)and CONSTANS-LIKE(COL)transcription factors are known to regulate a series of cellular processes,including the transition from vegetative growth to flower development in plants.However,their role in regula...CONSTANS(CO)and CONSTANS-LIKE(COL)transcription factors are known to regulate a series of cellular processes,including the transition from vegetative growth to flower development in plants.However,their role in regulating the fruit chlorophyll content is poorly understood.In this study,SlCOL1,the tomato(Solanum lycopersicum)ortholog of Arabidopsis CONSTANS,was shown to play key roles in controlling fruit chlorophyll.The suppression of SlCOL1 expression led to a reduction in the chlorophyll content of immature green fruit,while the overexpression of SlCOL1 increased it.An analysis of protein-protein interactions indicated that SlCOL1 forms a complex with GOLDEN2-LIKE(GLK2),which promotes the stability of its protein.The overexpression of SlCOL1in the glk2 null mutation background of tomato failed to promote chlorophyll accumulation in the immature green fruit,which suggests that GLK2 is required for the function of SlCOL1 in regulating chlorophyll content.These results shed new light on the mechanisms used by COL1 and GLK2 to regulate fruit development and chlorophyll accumulation in tomato.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 Natural Science Foundation of China(32360766,32072595 and 32202512)the Earmarked Fund for CARS(CARS-23-A13)。
文摘CONSTANS(CO)and CONSTANS-LIKE(COL)transcription factors are known to regulate a series of cellular processes,including the transition from vegetative growth to flower development in plants.However,their role in regulating the fruit chlorophyll content is poorly understood.In this study,SlCOL1,the tomato(Solanum lycopersicum)ortholog of Arabidopsis CONSTANS,was shown to play key roles in controlling fruit chlorophyll.The suppression of SlCOL1 expression led to a reduction in the chlorophyll content of immature green fruit,while the overexpression of SlCOL1 increased it.An analysis of protein-protein interactions indicated that SlCOL1 forms a complex with GOLDEN2-LIKE(GLK2),which promotes the stability of its protein.The overexpression of SlCOL1in the glk2 null mutation background of tomato failed to promote chlorophyll accumulation in the immature green fruit,which suggests that GLK2 is required for the function of SlCOL1 in regulating chlorophyll content.These results shed new light on the mechanisms used by COL1 and GLK2 to regulate fruit development and chlorophyll accumulation in tomato.
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.
