基于全基因组的茶树PAL家族基因鉴定及其在生物与非生物胁迫下的表达分析

Genome-wide Identification and Expression Analyses of PAL Genes Under Biotic and Abiotic Stress in Camellia sinensis

苯丙氨酸解氨酶(Phenylalanine ammonia-lyase,PAL)在植物物质代谢和抗逆过程中发挥重要作用。利用生物信息技术在茶树阿萨姆变种‘云抗10号’和茶变种‘龙井43’基因组中分别预测获得5条和6条PAL家族基因。系统发育树显示,拟南芥、杨树和茶树PAL亲缘关系较远,茶树阿萨姆变种和茶变种存在进化差异。对茶树转录组数据分析发现:盐胁迫和茉莉酸甲酯处理可显著诱导PAL家族基因表达,其对冷胁迫和干旱胁迫响应不显著,在茶树老叶中的表达较低,而在幼嫩组织和根中的表达均较高,其中PALa、PALc、PALe在花中表达最高。q RT-PCR结果表明,茶树炭疽菌(Colletotrichum camelliae)、拟盘多毛孢菌(Pseudopestalotiopsis camelliae-sinensis)和茶尺蠖(Ectropis oblique)接种处理茶变种‘龙井43’和新品系‘2807’24 h后,6个PAL家族基因均显著上调表达。以上结果表明,茶树PAL家族基因在应对不同逆境胁迫时发挥重要功能。

Phenylalanine ammonia-lyase(PAL)plays important roles in plant stress resistance.Based on bioinformatics analyses,five and six PAL genes were identified from the genomes of Camellia sinensis var.assamica‘Yunkang 10’and Camellia sinensis var.sinensis‘Longjing 43’respectively.Homology analysis showed that the CsPAL proteins had low homology to the proteins of Arabidopsis thaliana and Populus trichocarpa,and showed different evolutionary relationship between‘Longjing 43’and‘Yunkang 10’.Transcriptome data further showed that CsPAL genes could be significantly induced under salt stress and methyl jasmonate treatment,while not for cold and drought stresses.Tissue-specific expression of PAL genes showed relatively low transcript abundance in the old leaves of tea plant,but high in young tissues and roots,and particularly the expression of CsPALa,CsPALc,Cs PALe were the highest in flowers.Furthermore,qRT-PCR detection showed that the expression of six CsPAL genes were significantly up-regulated after inoculation at 24 h with Colletotrichum camelliae,Pseudopestalotiopsis camelliaesinensis and Ectropis oblique in‘Longjing 43’and new line‘2807’.The above results indicate that the PAL genes of tea plant play important roles in dealing with different stresses.