辣椒CaAUX22基因的克隆与表达分析

Cloning and Expression Analysis of CaAUX22 Gene in Pepper

AUX/IAA(生长素/吲哚-3-乙酸)基因家族是植物中重要的生长调控元件,主要调控植物生长素响应和信号传导。为揭示辣椒生长素原初响应基因CaAUX22的结构特征及功能,本研究以辣椒自交系6421为试验材料,克隆CaAUX22编码基因全长进行生物信息学和时空表达模式分析。结果发现,CaAUX22基因编码序列全长552 bp,编码183个氨基酸,蛋白分子量为20 798.85 Da,为亲水不稳定性蛋白。该蛋白不含信号肽,为非分泌蛋白,且不具有叶绿体、线粒体靶向肽。亚细胞定位预测CaAUX22蛋白位于细胞质中。蛋白跨膜结构预测显示CaAUX22蛋白不属于膜结构蛋白。进化树分析和同源基因序列比对表明CaAUX22与黄灯笼辣椒、曼陀罗、三分三的序列高度相似,均含有AUX/IAA结构域,且自身具有高度的保守性。RT-qPCR检测结果显示,辣椒CaAUX22基因在根和茎中微量表达,在花和叶中少量表达,在胎座和种子中表达相对较高,在果皮组织中表达量极高,并随着果实的生长其表达量逐渐升高,至成熟期降低,说明CaAUX22基因参与了辣椒果实的发育过程。这些结果为进一步研究辣椒CaAUX22基因的功能及其作用机制提供了理论依据。

The AUX/IAA(auxin/indole-3-acetic acid)gene family is one of the important regulators in plants,mainly regulating the response to auxin and signal transduction in plants.In order to reveal the structural characteristics and function of the primary response gene CaAUX22,the pepper inbred line 6421 was used as the material to clone the full length of CaAUX22 gene for bioinformatic analysis,and analyze its spatio-temporal expression pattern.The results showed that the coding sequence of CaAUX22 gene is 552 bp in length,encoding a hydrophilic instability protein with 183 amino acids and protein molecular weight of 20798.85 Da.Without signal peptide,it is a non-secreted protein and does not possess a chloroplast or mitochondrial targeted peptide.Subcellular localization predicts that the CaAUX22 protein is located in the cytoplasm.Prediction on the protein transmembrane structure reveals that the CaAUX22 protein is not a membrane structural protein.Evolutionary tree analysis and sequence alignment showed that CaAUX22 was highly similar to its homologous genes in Yellow Lantern pepper,Mandala,and Shanfenshan,which contain the highly conserved AUX/IAA domains.RT-qPCR showed that the transcript abundances of CaAUX22 gene were very low in roots and stems,low inflowers and leaves,relatively high in fetuses and seeds,and extremely high in peel tissue.Meanwhile,expression of CaAUX22 was gradually increased with the fruit growth and then decreased until maturity,indicating that CaAUX22 is involved in the development of pepper fruit.These results provide substantial information for further studies on the function of pepper CaAUX22 gene and its mechanism of action.