Yellow nutsedge WRI3/4-like gene improves drought tolerance in Arabidopsis thaliana by promoting cuticular wax biosynthesis

Abstract

In this study we cloned a WRI1-like gene from yellow nutsedge. Conserved domain and phylogenetic analyses indicated it to be a WRI3/4-like gene. Arabidopsis plants transformed with WRI3/4-like gene showed significantly improved tolerance to both PEG-simulated drought stress and real dehydration compared with the wild type. Quantitative RT-PCR indicated that, under unstressed conditions, the expressions of key genes involved in fatty acid biosynthesis was not significantly different between wild type (WT) and transgenic lines, while the expressions of genes involved in cuticular wax biosynthesis was significantly higher in transgenic lines compared with the wild type. The PEG treatment slightly decreased the expression of above mentioned genes in WT plants while it was significantly increased in transgenic lines compared with their respective unstressed control. Without PEG treatment, the expression of TAG1, the gene involved in triacylglycerol (TAG) accumulation, was 10-40% lower in the transgenic lines than that in the wild type. However, after PEG treatment, the expression of TAG1 was slightly decreased in the wild type, while in the transgenic lines its expression was decreased by 20-70% compared with unstressed transgenic lines and was highly significantly lower than that in the wild type. The cuticular wax content in Arabidopsis leaves was significantly higher in the transgenic lines than that in the wild type, while the oil content was not significantly different.