Induced Mutations for Plant Breeding·Agricultural Biotechnology
LI Ziyang, YANG Kebin, ZHU Chenglei, LIU Yan, GUO Dong, XIAO Xiaoyan, GAO Zhimin
The ATP-binding cassette subfamily G (ABCG) plays a crucial role in the transport of substances in plant. In order to explore the molecular characteristics, expression patterns and regulatory relationships of ABCGs in moso bamboo (Phyllostachys edulis), bioinformatics methods were used to identify the gene members of ABCG subfamily in moso bamboo. Moreover, the comprehensive analysis of the gene structure, physiochemical properties of protein and phylogenetic relationship was conducted, and the gene expression patterns were analyzed by quantitative real-time PCR (qRT-PCR). Furthermore, the regulatory relationship between transcription factors and ABCG gene was verified by yeast one-hybrid assay. The results showed that there were 77 ABCGs identified inmoso bamboo (PeABCG1~PeABCG77). A variety of hormone, abiotic stress response elements were found in the promoters of PeABCGs, among which the ABRE element in response to the abscisic acid (ABA) was the most, and appeared in the promoters of 74 PeABCGs. Phylogenetic analysis showed that PeABCGs were divided into white-brown complex (WBC) and pleiotropic drug resistance (PDR) subgroups, which were closely related to those of rice. The results of qRT-PCR demonstrated that six of seven PeABCGs associated with ABA transport were up-regulated under ABA treatment, whereas PeABCG34 was undetected. All the expressions of seven PeABCGs were induced by low temperature. The expression of two PeABCGs was inhibited, while those of other five genes were induced with different levels of drought treatment. Besides, the expressions of PeABCG15 in shoots was continuously up-regulated with the increasing degree of lignification, consistent with the expression trend of PeKNAT3 and PeMYB42 involved in regulating lignin synthesis. It was confirmed that PeKNAT3 and PeMYB42 could bind to the promoter of PeABCG15 by yeast one-hybrid assay. These results suggested that PeABCGs may participate in the resistance of moso bamboo in two ways: ABA-mediated and non-ABA-mediated, among which PeABCG15 was induced by ABA and may be involved in stress resistance by promoting lignin synthesis. These findings would provide references for revealing the biological functions of ABCG in moso bamboo.