茶树脯氨酸转运蛋白基因鉴定及表达分析

Identification and Expression Profiling Analysis of CsProTs Gene Family in Tea Plant

脯氨酸转运蛋白在植物体内脯氨酸的分配及响应多种非生物逆境胁迫过程中发挥着重要作用。为明确茶树体内脯氨酸转运蛋白家族情况,该研究从全基因组水平鉴定获得茶树脯氨酸转运蛋白家族成员,进行了系统进化关系、蛋白结构、基因表达特异性等分析。结果表明:(1)茶树中有6个脯氨酸转运蛋白基因,长度为1326~1725 bp之间,编码氨基酸数目在441~574 aa之间,蛋白质分子质量在48.5~63.0 kD之间,等电点为8.51~9.41,大部分为碱性蛋白,其结构中含有大量的α-螺旋和自由卷曲,少量的延长链和β-转角结构。(2)亚细胞定位分析结果显示,茶树CsProT1、CsProT2、CsProT4、CsProT5和CsProT6蛋白定位于细胞膜,CsProT3蛋白则定位于高尔基体。(3)CsProTs蛋白中含9~11个典型的跨膜结构域,其三级结构与保守基序特征均与拟南芥高度相似,具有高度的保守性,不同成员间氨基酸序列相似性达40.14%。(4)基因表达特异性分析显示,CsProT1,CsProT2和CsProT3基因在各个组织部位的表达量均较高,CsProT4、CsProT5和CsProT6表达量均较低,且CsProT1基因的表达量最高;除CsProT5基因外,CsProTs蛋白家族的基因均受到NaCl、干旱及冷胁迫的诱导表达。(5)蛋白相互作用分析结果显示,CsProTs蛋白可与脯氨酸氧化酶ERD5,脯氨酸生物合成限速酶P5CS1、P5CS2和δ-吡咯啉-5-羧酸脱氢酶ALDH12A1等脯氨酸合成,转运及降解有关的蛋白相互作用,共同调控茶树体内脯氨酸的含量。研究认为,茶树6个CsProTs蛋白可共同参与茶树体内脯氨酸的转运平衡及对多种非生物逆境胁迫响应的过程。

The proline transporter protein(ProTs)family plays an important role in proline distribution and protective stress responses in plants.To understand the profile of ProTs in tea plant,we used the bioinformatics methods to identify the members of CsProTs from genome of tea plant,and analyzed their phylogenetic relationship,protein structure and gene expression patterns in the present study.The results showed that:(1)there were six CsProT genes in tea plant:CsProT1,CsProT2,CsProT3,CsProT4,CsProT5 and CsProT6;We found that the number of amino acids encoded by CsProTs genes in tea plant is ranged from 441 to 574,the IP is covered from 8.51 to 9.41 and the molecular weight is distributed from 48.5 to 63.0 kDa;Most of them are basic proteins,which containing a large number ofα-helix,free curls,a small number of elongation chains andβ-corner structures.(2)The subcellular localization analysis showed that CsProT1,CsProT2,CsProT4,CsProT5 and CsProT6 were located in cell membrane,but CsProT3 located in Golgi.(3)The prediction results from amino acid sequences showed that each of CsProTs contained 9-11 transmembrane domains.The conservative motif analysis showed that the ProTs had high conservation in tea plant and Arabidopsis,and the consistency of amino acid sequence among different members was as high as 40.14%.(4)CsProT1,CsProT2 and CsProT3 genes were highly expressed in all tissues of tea plant,but CsProT4,CsProT5 and CsProT6 genes were low;And except CsProT5 gene,CsProTs genes were all induced by NaCl,drought and cold stress in the leaves of tea plant.(5)The protein-protein interaction analysis showed that CsProTs could interact with proline oxidase ERD5,proline biosynthesis rate limiting enzymes P5CS1,P5CS2,δ-pyrroline-5-carboxylic acid dehydrogenase ALDH12A1 and other proteins related to proline synthesis,transport,degradation and jointly regulate proline content in tea plant.In conclusion,there were six CsProTs in tea plant,which are widely involved in the regulation of proline homeostasis and responding to different abiotic stress.