百香果苯丙氨酸解氨酶基因PePAL克隆及表达分析

Cloning and Expression Analysis of Phenylalanine Ammonia‑lyase Gene PePAL in Passion Fruit

为探讨百香果中苯丙氨酸解氨酶(PAL)编码基因的序列结构和蛋白质功能,以台农1号百香果(Passiflora edulis Sims)为材料,以cDNA为模板对PePAL基因进行同源克隆,同时对PePAL编码蛋白质的结构及功能进行预测。结果表明,PePAL基因cDNA全长2499 bp,含有1个完整开放阅读框(2124 bp),编码707个氨基酸,蛋白质分子质量为173.43 ku。利用ProtParam、SignalP 4.1软件及TMHMM等软件对PePAL蛋白的结构预测显示,该蛋白质是一个亲水性的非分泌型蛋白,无跨膜结构域,无信号肽。PePAL主要定位于细胞核、叶绿体、细胞质、细胞膜、线粒体、液泡等部位,其二级结构由α螺旋、延伸链、β转角及无规则卷曲组成。PePAL在不同品种百香果的同一结果枝上的表达模式均呈现花中表达量最高,其次是茎,在成熟叶中表达量最低。

Phenylalanine ammonia‑lyase(PAL)is involved in the formation of secondary metabolism of lignin,flavonoids and coumarines,and plays an important role in plant disease resistance,insect resistance,stress resistance and growth and development.In order to explore the gene sequence structure and protein function of PAL in Passiflora edulis Sims,the“Tainong 1”Passiflora edulis Sims was used as the material and the cDNA was used as the template for homologous cloning of the PePAL gene.At the same time,the structure and function of the PePAL coding protein were predicted.The results showed that the cDNA of PePAL gene was 2499 bp in length,containing a complete open reading frame(ORF)of 2124 bp,encoding 707 amino acids,with a molecular weight of 173.43 ku.The structural prediction of PePAL protein using ProtParam,SignalP4.1 and TMHMM softwares showed that the protein was a hydrophilic non‑secretory protein without transmembrane domain and signal peptide.PePAL was mainly located in the nucleus,chloroplast,cytoplasm,cell membrane,mitochondria,vacuoles and other parts,and its secondary structure was composed ofα‑helix,extended strand,β‑turn and random coil.The expression of PePAL was the highest in flowers on the same fruiting branch of passion fruit,followed by stems,and the lowest in mature leaves.