Identification and Expression Analysis of LBD Genes in Moso Bamboo (Phyllostachys edulis)

The Lateral Organ Boundaries Domain (LBD) proteins are a class of plant-specific transcription factor family, which participate in plant growth, development, and stress response. In present study, 61 PheLBD genes were identified in moso bamboo (Phyllostachys edulis) genome. These members clustered into two major classes (Class I and Class II) based on the previous study and phylogenetic analysis, and Class I was further divided into five subgroups (Class I-Class E). The gene architecture and conserved motifs suggested the members in one subgroup shared the structural similarities and highly conserved motif compositions. Scaffold position analysis showed PheLBDs were unevenly located on 19 moso bamboo scaffolds. Synteny analysis indicated segmental duplication and transposed duplication played significant roles in PheLBD gene expansion and some PheLBD genes have been and are undergoing markedly positive purifying selection during evolution. A large number of light-responsive elements, abiotic-stress and hormone-response elements were discovered in the promoter of PheLBDs. Public RNA-seq data helps to analyze the expression profile of PheLBD genes in 14 moso bamboo tissues. And we also found most genes in class II were significantly up-regulated under auxin naphthaleneacetic acid (NAA) treatment, but were sensitive after Gibberellins (GA)-treated. Moreover, quantitative real-time reverse transcription PCR (RT-qPCR) analysis showed that PheLBDs have different response to salt and drought stress as well as abscisic acid (ABA) and Methyl jasmonate (MeJA). Overall, these results paved a way for the further functional studies of PheLBDs.