The responses of sulforaphane synthesis and endogenous NO to Penicillium chrysogenum elicitor in Broccoli cells

Abstract

In this study, we investigated the effects Penicillium chrysogenum elicitor and NO synthesis inhibitor on phenylalanine ammonia lyase (PAL) activity, cell viability, endogenous nitric oxide (NO) and NO synthase (NOS) and nitrate reductase (NR), secondary metabolite sulforaphane accumulation. In addition, the link of between endogenous nitric oxide (NO) and sulforaphane, as well as between NR and NOS pathway was also assessed. The results showed that all the concentrations of Penicillium chrysogenum elicitor induced NO synthesis, and the synthesis reaction time was earlier under high concentrations of Penicillium chrysogenum elicitor, while the released rate of NO was relatively slower under low concentration of Penicillium chrysogenum elicitor. In addition, NO scavenger carboxy-PTIO (c-PTIO) blocked the effect of Penicillium chrysogenum elicitor on the promotion that sulforaphane accumulation and the activation of PAL activity, and decrease cell vitality induced by Penicillium chrysogenum elicitor. The content of sulforaphane was related with NO accumulation, and the accumulation of sulforaphane was increased when endogenous NO release was excited, while sulforaphane accumulation amount decreased when NO synthesis was inhibited. Under the induction of Penicillium chrysogenum elicitor, the release of NO from in vitro cells of broccoli was mainly through NOS and NR pathways. When NR pathway was inhibited by high concentrations of NR inhibitor Tungstate, NOS activity was activated via high concentration of K+ from Tungstate. However, NR pathway could not be activated by high concentration of K+ when the NOS pathway was inhibited by NOS inhibitor L-NAME.