Genome-Wide Identification of the CER1 Gene Family in Plants and Stress-Responsive Expression of the MdCER1 Genes

Abstract

Plant cuticular wax is an important factor affecting the growth and quality of plants through protecting the plant from drought, and other diseases. It is reported that CER1 encodes a core enzyme involved in VLC alkane biosynthesis which can affect plant response to stress, but no characterization of CER1 gene and its family has been reported in apples. In this study, we identified 3 MdCER1 genes in Malus domestica and named MdCER1-1 to MdCER1-3, then we analyzed their sequences feature, expression patterns to screen highly expressed genes for cloning and functional verification. Expression analysis by real-time PCR showed that drought stress could induce MdCER1-like overexpression. The experiment of water loss showed that overexpression of MdCER1-like could effectively prevent water loss in apple calli, and the effect was more significant under drought stress. Meanwhile, the expression of wax metabolism related genes MdYPB5, MdCER3 and MdKCS1 was significantly up-regulated, GC-MS analysis of wax fraction showed that overexpression of MdCER1-like significantly increased the content of alkanes. The enzyme activities (SOD, POD) of overexpressed apple calli increased signifcantly, while the contents of malondialdehyde and proline decreased. In a word, MdCER1-like plays an important role in wax metabolism and tissue water retention, and provides a theoretical basis for exploring its role in drought stress.