Functional and RNA-Sequencing Analysis Revealed Expression of a Novel Stay-Green Gene from () Caused Chlorophyll Degradation and Accelerated Senescence in Arabidopsis.

Senescence is not only an important developmental process, but also a responsive regulation to abiotic and biotic stress for plants. Stay-green protein plays crucial roles in plant senescence and chlorophyll degradation. However, the underlying mechanisms were not well-studied, particularly in non-model plants. In this study, a novel stay-green gene, , was isolated from . Subcellular localization result demonstrated that ZjSGR was localized in the chloroplasts. Quantitative real-time PCR results together with promoter activity determination using transgenic Arabidopsis confirmed that could be induced by darkness, ABA and MeJA. Its expression levels could also be up-regulated by natural senescence, but suppressed by SA treatments. Overexpression of in Arabidopsis resulted in a rapid yellowing phenotype; complementary experiments proved that was a functional homolog of from . Over expression of accelerated chlorophyll degradation and impaired photosynthesis in Arabidopsis. Transmission electron microscopy observation revealed that overexpression of decomposed the chloroplasts structure. RNA sequencing analysis showed that could play multiple roles in senescence and chlorophyll degradation by regulating hormone signal transduction and the expression of a large number of senescence and environmental stress related genes. Our study provides a better understanding of the roles of s, and new insight into the senescence and chlorophyll degradation mechanisms in plants.