Capsicum chinenseJacq. derived glutaredoxin (CcGRXS12) alters phytohormonal pathways and redox status of the cells to confer resistance against pepper mild mottle virus (PMMoV-I)

Abstract

AbstractGlutaredoxins (Grxs) are small, ubiquitous, multi-functional proteins present in different compartments of plant cells. A chloroplast targeted class I GRX (CcGRXS12) gene was isolated fromCapsicum chinenseduring the pepper mild mottle virus (PMMoV) infection. Functional characterization of the gene was performed inN. benthamianatransgenic plants transformed with nativeC. chinense GRX(Nb:GRX),GRX-fused with GFP (Nb:GRX-GFP) andGRXtruncated for the chloroplast targeting sequences but fused with GFP (Nb:Δ2MGRX-GFP). Over-expression ofCcGRXS12inhibits the PMMoV-I accumulation at late stage of infection and is accompanied with the activation of SA- pathway pathogenesis related (PR) transcripts, and suppression of JA/ET- pathway transcripts. Further the reduced accumulation of auxin-induced Glutathione-S-Transferase (pCNT103) inCcGRXS12over expressing lines indicates that the protein could able to protect the plants from the oxidative stress caused by the virus. PMMoV-I infection increases accumulation of pyridine nucleotides (PNs) mainly due to the reduced form of PNs (NAD(P)H) and it was higher inNb:GRX-GFPlines compared to other lines where infection is limited. Apart from biotic stress,CcGRXS12protects the plants from abiotic stress conditions caused by H2O2and herbicide paraquat. CcGRXS12 exhibits GSH-disulphide oxidoreductase activityin vitrohowever devoid of complementary Fe-S cluster assembly mechanism in yeast.