Diphenyleneiodonium delays the deposition of suberin polyphenolic and lignin at wounds of potato tubers by inhibiting Strbohs transcription and NADPH oxidase activity

Abstract

Diphenyleneiodonium (DPI) is a specific and effective inhibitor of NADPH oxidase (NOX). However, there are no reports on whether DPI affects the transcription of Strbohs family members, and the accumulation of suberin polyphenolic (SPP) and lignin of potato tubers during healing. In this study, DPI treatment was shown to exert an inhibitory effect on the expression of Strbohs at the wound tissue, especially StrbohA, StrbohB, and StrbohE. DPI clearly reduced the activity of NOX and superoxide dismutase, and decreased O2− and H2O2 accumulation. DPI also decreased the activity of phenylalanine ammonia-lyase, cinnamate-4-hydroxylase, 4-coumarate-CoA ligase, and cinnamyl alcohol dehydrogenase as well as the contents of total phenolics and lignin. Moreover, DPI caused the lower deposition amount of SPP and lignin at wounds of potato tubers. Above results suggested that DPI led to the less SPP and lignin deposition at the wound surfaces by decreasing H2O2 production via Strbohs / NOX and suppressing phenylpropanoid metabolism in potato tubers.