Salicylic acid treatment alleviates the loss of glucosinolates accompanying yellowing in harvested broccoli

Abstract

Commercial value of broccoli is seriously affected by the deterioration of its organoleptical and nutritional quality after harvest. Here, we treated broccoli with salicylic acid (SA) to evaluate its impact on the yellowing process and its protective effect on glucosinolates content during shelf life. SA treatment visibly postponed the yellowing process, as evidenced by higher chlorophyll content and h◦ values as well as lower L* values and yellowing index. Meanwhile, higher levels of glucoraphanin, glucobrassicin, and neoglucobrassicin were accumulated in the treatment group. It was attributed to the activation of glucosinolates biosynthetic capacity by SA treatment, as evidenced by the up-regulated expressions of key regulators BoBCAT3, BoCYP83A1, BoCYP83B1, BoMYB28, BoMYB34, and BoMYB122. In addition, the treatment suppressed the increment of ethylene release while facilitating the biosynthesis of endogenous SA, brassinolide, and jasmonic acid. Statistical analysis provided evidence for SA treatment directly promoting glucosinolate biosynthesis in broccoli and indirectly mitigating glucosinolates loss through hormonal interactions.