Genome-Wide analysis of the AAAP gene family in moso bamboo (Phyllostachys edulis)

Background: Members of the amino acid/auxin permease (AAAP) gene family play indispensable roles in various plant metabolism and biosynthesis processes. Comprehensive analysis of AAAP genes has been conducted in Arabidopsis, rice, maize and poplar, but has not been reported from moso bamboo. Phylogenetics, evolutionary patterns and further expression profiles analysis of the AAAP gene family in moso bamboo (Phyllostachys edulis) will increase our understanding of this important gene family. Results: In this current study, we conducted phylogenetic, gene structure, promoter region, divergence time, expression patterns and qRT-PCR analysis of the 55 predicted AAAP genes in moso bamboo based on the availability of the moso bamboo genome sequence. We identified 55 putative AAAP (PeAAAP1-55) genes, which were divided into eight distinct subfamilies based on comparative phylogenetic analysis using 184 full-length protein sequences, including 55 sequences from moso bamboo, 58 sequences from rice and 71 sequences from maize. Analysis of evolutionary patterns and divergence showed that the PeAAAP genes have undergone a extensive duplication event approximately 12 million years ago (MYA) and that the split between AAAP family genes in moso bamboo and rice occurred approximately 27 MYA. The microarray analysis suggested that some genes play considerable roles in moso bamboo growth and development. We investigated the expression levels of the 16 AAP subfamily genes under abiotic stress (drought, salt and cold) by qRT-PCR to explore the potential contributions to stress response of individual PeAAAP genes in moso bamboo. Conclusions: The results of this study suggest that PeAAAP genes play crucial roles in moso bamboo growth and development, especially in response to abiotic stress conditions. Our comprehensive, systematic study of the AAAPs gene family in moso bamboo will facilitate further analysis of the functions and evolution of AAAP genes in plants.