Horticulture Research | 2021
CCCH protein-PvCCCH69 acted as a repressor for leaf senescence through suppressing ABA-signaling pathway
Abstract
CCCH is a subfamily of zinc finger proteins involved in plant growth, development, and stresses response. The function of CCCH in regulating leaf senescence, especially its roles in abscisic acid (ABA)-mediated leaf senescence is largely unknown. The objective of this study was to determine functions and mechanisms of CCCH gene in regulating leaf senescence in switchgrass ( Panicum virgatum ). A CCCH gene, PvCCCH69 (Pv C3H69) , was cloned from switchgrass. Overexpressing Pv C3H69 in rice suppressed both natural senescence with leaf aging and dark-induced leaf senescence. Endogenous ABA content, ABA biosynthesis genes ( NCED3, NCED5 , and AAO3 ), and ABA signaling-related genes ( SnRKs , ABI5 , and ABF2/3/4 ) exhibited significantly lower levels in senescencing leaves of PvC3H69- OE plants than those in WT plants. Pv C3H69 -suppression of leaf senescence was associated with transcriptional upregulation of genes mainly involved in the light-dependent process of photosynthesis, including light-harvesting complex proteins, PSI proteins, and PSII proteins and downregulation of ABA biosynthesis and signaling genes and senescence-associated genes. PvC3H69 could act as a repressor for leaf senescence via upregulating photosynthetic proteins and repressing ABA synthesis and ABA signaling pathways.