Identification of PAL Gene in Purple Cabbage and Functional Analysis Related to Anthocyanin Synthesis
Jun Tian, Ru Xu, Kaizhen Chang, Yuan Song, Chenxin Huang, Jinwei Wang, Shuhao Li, Fazhong Liu, Fenglin Zhong
Abstract
Anthocyanin is a characteristic nutrient of purple cabbage, and phenylalanine ammonia-lyase (PAL) is the rate-limiting enzyme for the synthesis of anthocyanin by the phenylpropane pathway, which is an important part of plant secondary metabolism. In this research, 7 BrPAL, 8 BoPAL, and 15 BnPAL genes from genomes of Brassica rapa, Brassica oleracea, and Brassica napus, divided into four subgroups, evolved from 4 PAL genes in Arabidopsis. The amplification and evolution of the BrPAL gene are due to segmental duplication and purifying selection. BrPAL genes clustered in the same clade have similar intron/exon structures and motifs. The cis-regulatory elements are divided into four categories: light, growth and development, stress and hormones. The qRT-PCR assays showed that most BrPAL genes were upregulated by UVA, low temperature and MeJA and downregulated by FR, high temperature, salt, PEG, IAA, ABA and GA, and there was a positive correlation between anthocyanin content and gene expression. This study can be used as a source for the function of the cabbage PAL gene and its molecular mechanism of regulating anthocyanin synthesis and provides a theoretical basis for the molecular breeding of cabbage.