毛竹C4H基因的鉴定及其表达模式分析

Identification and Expression Pattern Analysis of C4H Genes in Phyllostachys edulis

摘要:

为了解毛竹（Phyllostachys edulis）中肉桂酸-4-羟化酶基因（C4H）的分子特征及其表达模式，采用生物信息学方法在毛竹基因组数据库中鉴定出6个C4H成员（PeC4H1~PeC4H6），基因编码区长度为1 506~1 695 bp，推测编码501~564 aa，均具有保守的血红素结合域、苏氨酸结合槽基序和5个特征性底物识别位点，属于细胞色素P450超家族。系统进化分析表明，6个PeC4Hs可分为2类，分别含有2和4个成员。转录组数据分析表明，PeC4Hs在毛竹26个组织中的表达量存在明显差异，不同高度笋中PeC4Hs的表达差异显著。PeC4Hs启动子序列中含有多种响应逆境胁迫和激素信号的顺式调控元件，PeC4Hs表达受干旱和GA₃的影响，干旱时，仅PeC4H3/4在根中显著上调表达，其余成员均呈下调表达；GA₃处理下叶中PeC4H3/6迅速响应，呈先显著上调后逐渐降低的趋势，根中PeC4H2/5在处理前1 h短暂下调后又显著上调，至8 h时恢复到处理前的表达水平。因此，PeC4Hs可能在毛竹笋的木质化过程和应对非生物胁迫中发挥着重要作用。

Abstract:

To reveal the molecular characteristics and expression pattern of C4H genes in moso bamboo (Phyllostachys edulis), six C4H gene members (PeC4H1-PeC4H6) from moso bamboo genomic database were identified by bioinformatics method. The length of gene coding region ranged from 1 506 to 1 695 bp, encoding 501-564 aa, and all of them have conserved heme binding domain, threonine binding channel motif and five characteristic substrate recognition sites, which belong to the cytochrome P450 superfamily. Phylogenetic analysis showed that the six PeC4Hs could be divided into two classes, containing 2 and 4 members, respectively. Transcriptome analysis showed that there were significant differences in the expression of PeC4Hs in 26 tissues of moso bamboo, and the expression of PeC4Hs in bamboo shoots at different heights were different by qPCR. There were a variety of cis-regulatory elements in response to stress and hormone signals in the promoter sequences of PeC4Hs. The expression of PeC4Hs was affected by drought and GA₃. Under drought, only PeC4H3/4 expression was significantly up-regulated in roots, while others were down-regulated. Treated by GA₃, the expression of PeC4H3/6 in leaves was responded rapidly and significantly up-regulated at first and then gradually decreased. The expression of PeC4H2/5 in roots was briefly down-regulated in the first hour and then significantly increased, finally recovered to the untreated level at 8 h. Therefore, PeC4Hs might play an important role in the lignification process of bamboo shoot and the response to abiotic stress.