Assessment of changes in the content of sulforaphane and expression levels of CYP79F1 and myrosinase genes and proteomic profile of Lepidium draba plant under water-deficit stress induced by polyethylene glycol

Abstract

Lepidium draba weed, which has a very valuable secondary metabolite named sulforaphane, is a precious medicinal plant that very few studies have been done on it. In this study, 5-day-old Lepidium draba plants were grown for 9 days in differentially levels of polyethylene glycol and the amount of total Phenols, total Flavonoids, total Anthocyanins, sulforaphane, chlorophyll and Carotenoids as well as cytochorome P450 79F1 and myrosinase genes expression levels, which are two main genes in the biosynthesis pathway of sulforaphane, were investigated in14-day-old sprouts of these plants. Our results showed that with increasing doses of polyethylene glycol, the contents of total Phenols, total Flavonoids, total Anthocyanins and sulforaphane increased, while chlorophyll and Carotenoids contents decreased. In addition, cytochorome P450 79F1 and myrosinase genes expression levels increased with enhancement of polyethylene glycol levels. A direct relationship was observed between sulforaphane content and cytochorome P450 79F1 and myrosinase genes expression together and also with enhancement of polyethylene glycol concentrations. To determine the protein changes in the Lepidium draba plant under water-deficit stress, a proteomics study was carried out on total 14-day-old sprouts of this plant by two-dimensional electrophoresis (2-DE) based on proteomics method under non stress (polyethylene glycol 0%), and medium stress (polyethylene glycol 6%) conditions. We have for the first time found that glutamate 5-kinase, 3′-5′ exonuclease and Sigma-54-dependent Fis family transcriptional regulator, were changed remarkably in plant in response to abiotic stress.