青稞GPAT基因家族全基因鉴定及表达分析

Identification and expression analysis of GPAT gene family in hulless barley

甘油-3-磷酸酰基转移酶(glycerol-3-phosphate acyltransferase,GPAT)是一类膜结合酶,催化甘油脂质生物合成的起始步骤,在植物生长、发育和逆境胁迫反应过程中发挥着重要作用。本研究利用青稞‘拉萨钩芒’和‘藏青320’基因组为参考基因组,通过鉴定青稞GPAT基因家族成员,开展其基因结构、进化关系、顺式作用元件等生物信息学分析,并对其非生物胁迫下表达模式进行分析。结果表明:共鉴定出21个青稞GPAT家族成员,按染色体位置命名为HvGPAT1~HvGPAT21,除HvGPAT21基因染色体位置未知,其余20个基因不均匀分布在青稞7条染色体上。理化性质分析表明该家族成员编码213~847个氨基酸,理论等电点在4.93~10.58。系统进化分析将其分为三类,GroupⅠ类(6个)、GroupⅡ类(1个)和GroupⅢ类(14个),各类间基因结构和保守基序差异明显;在HvGPATs基因启动子区域广泛预测到3种胁迫响应元件[防御和压力响应元件(TC-rich repeats)、干旱响应元件(MBS)、低温响应元件(LTR)]和5种激素响应元件[脱落酸反应元件(ABRE)、生长素响应元件(TGA-element)、赤霉素响应元件(GARE-motif和P-box)、茉莉酸甲酯(MeJA)反应元件(TGACG-motif和CGTCA-motif)和水杨酸反应元件(TCA元件)],表明该家族与非生物胁迫有关。qRT-PCR分析表明:冷胁迫下HvGPAT1在叶中表达量相对较高,HvGPAT14和HvGPAT18在根中表达量升高;干旱胁迫下HvGPAT14在叶中的表达量上调;盐胁迫下HvGPAT4和HvGPAT18在叶中的表达量显著升高,HvGPAT4在根中表达量会显著上升。

Glycerol-3-phosphate acyltransferase(GPAT)is a kind of membrane-bound enzyme,which catalyzes the initial step of glycerol lipid biosynthesis and plays an important role in plant growth,development and stress response.In this study,hulless barley(Hordeum vulgare var.nudum)‘Lhasa hook awn’and‘Zangqing320’were used as reference genomes to identify the members of hulless barley GPAT gene family,analyzed their gene structure,evolutionary relationship,cis-acting elements and abiotic stress expression.The results showed that 21 members of hulless barley GPAT family were identified and named HvGPAT1–HvGPAT21 according to chromosome position.Except that the chromosome position of HvGPAT21 gene was unknown,the other 20 genes were unevenly distributed on seven chromosomes.The analysis of physical and chemical properties showed that the family members encoded 213-847 amino acids,and the theoretical isoelectric point was 4.93–10.58.Phylogenetic analysis showed that they can be divided into three categories:GroupⅠ(6),GroupⅡ(1)and GroupⅢ(14),which there were significant differences in gene structure and conserved motifs among different types.Three abiotic stress response elements[defense and pressure response element(TC-rich repeats),drought response element(MBS),low temperature response element(LTR)]and five hormone response elements[abscisic acid response element(ABRE),auxin response element(TGA-element),gibberellin response element(GARE-motif and P-box),methyljasmonic acid(MeJA)response element(TGACG motif and CGTCA motif),salicylic acid response element(TCA element)]were predicted in the promoter region of HvGPAT genes,indicating that this family is related to abiotic stress.qRT-PCR results showed that under cold stress,the expression level of HvGPAT1 was relatively high in leaves,and the expression levels of HvGPAT14 and HvGPAT18 were increased in roots.The expression of HvGPAT14 in leaves was up-regulated under drought stress.Under salt stress,the expression levels of HvGPAT4 and HvGPAT18 in leaves were increased significantly,and as did the expression level of Hv GPAT4 in roots.