CCCH protein-PvCCCH69 acted as a repressor for leaf senescence through suppressing ABA-signaling pathway

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(PvC3H69),was cloned from switchgrass.Overexpressing PvC3H69 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.PvC3H69-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.

Effect of Echinacea Polysaccharide on Secretion of IkB-αmRNA by IEC-6 Injured by LPS

[ Objective] This study was conducted to investigate the mechanism of Echinacea polysaccharide （EPS） in treatment of various bacterial infection and reduction of inflammation, so as to provide a theoretical basis for clinic application of EPS. [ Method ] Nuclear protein extracted from six groups, the normal control group, the simple lipopolysaccharide （LPS） group and the EPS （ with concentrations of 50,100,200 and 500 μg/ml, respectively） ＋ LPS groups was subjected to SDS-PAGE electrophoresis, and pIkB-α protein contents in the extracts were analyzed by Coomassie brilliant blue （CBB） staining and Western-Blot method. [ Result] The simple LPS group showed the highest pIkB-α protein level, and in the EPS concentration range of 0 -200 μg/ml, the expression level of pIkB-α pro- tein was improved with the increase of EPS concentration. [ Conclusion The expression level of pIkB-α protein was improved under the simulation of IEC-6 by LPS, while EPS could effectively inhibit the expression of pIkB-α protein. The expression level of pIkB-α was the lowest in the LPS ＋500 μg/ml EPS group.