Abstract: [Objective] The SBP family genes encode a class of transcription factors which recognize and bind to the promoter of the MADS-box gene SQUAMOSA (SQUA), and regulate plant growth and reproductive growth. Systematic identification and analysis of Phyllostachys edulis SBP family genes can help to understand the role of them in vegetative growth and reproductive growth of P. edulis, and lay a foundation for gene functional analysis of SBP family genes in P. edulis.[Method] The SBP family genes were identified by bioinformatics methods using published P. edulis genomic data. The basic biological information of P. edulis SBP family genes was analyzed by using MEGA 6.0,DNAMAN, psRNATarget and other bioinformatics software. The expression patterns of P. edulis SBP family genes were studied by using the quantitative real-time fluorescence PCR (qPCR) in different tissues including leaf, root and stem, during floral development and under high salt stress.[Result] A total of 18 SBP family genes were identified in the genome of P. edulis, and these genes had a single and highly conserved SBP domain, of which 10 SBP family genes had miR156 target sites. There are 74 amino acid residues in the SBP domain of P. edulis, including two zinc finger domains and one NLS domain. The SBP transcription factors with close evolutionary relationship have similar motif distribution pattern and gene structure. The phylogenetic analysis of the SBP family gene of different species showed that the SBP family genes of P. edulis were closely related to the SBP family in rice. The qPCR result showed that, the relative expression levels of PeSBP11 and PeSBP16 were the highest in stems and roots, respectively. There were six genes (PeSBP1, PeSBP2, PeSBP3, PeSBP7, PeSBP15 and PeSBP17) with relatively low expression levels and no obvious change of expression abundances at P1-P4 stages (early in the formation of inflorescence (P1), the differentiation of spikelet (P2), the differentiation of floret (P3), the growth of spikelet (P4)) during the development of inflorescences. And seven genes (PeSBP5, PeSBP9, PeSBP10, PeSBP12, PeSBP14, PeSBP16 and PeSBP18) expression level increased in the P1-P2, of which high expression level of PeSBP10 and PeSBP14 continued to P3 phase. Seven genes (PeSBP6, PeSBP8, PeSBP9, PeSBP10, PeSBP14, PeSBP16 and PeSBP18) had a higher expression level than other genes in P3. Five genes (PeSBP4, PeSBP5, PeSBP9, PeSBP13 and PeSBP16) had the higher expression value than other genes at stage P4. The relative expression levels of PeSBP2, PeSBP3, PeSBP4, PeSBP8, PeSBP10, PeSBP11, PeSBP12 and PeSBP14 increased gradually with the prolonging of treatment time under high salt stress.[Conclusion] P. edulis SBP family genes were relatively conserved in evolution, and there is not novel SBP genes found in P. edulis genome. qPCR analysis showed that the SBP family genes of P. edulis were involved in the growth of vegetative organs of P. edulis, and played an important role in the flowering process of P. edulis. Under the high salt stress, the expression of four SBP family genes were significantly increased, which were involved in the response to high salt stress.

Key words: Phyllostachys edulis, SBP family genes, gene expression pattern, development of inflorescences, salt stress