地黄氧-酰基转移酶WSD基因的鉴定与表达分析

Identification and expression analyses of O-acyltransferase WSD genes in Rehmannia glutinosa

关键词:  地黄, 氧-酰基转移酶WSD, 生物信息学分析, 基因表达, 镉胁迫

Key words:  Rehmannia glutinosa, O-acyltransferase WSD, bioinformatics, gene expression, cadmium stress

摘要:

植物蜡酯合成酶催化长链醇和长链脂肪酸合成蜡酯,对植物蜡质合成及其抗旱、抗致病菌袭击和紫外辐射、抗寒和昆虫侵害等环境胁迫具有非常重要的作用; 镉是环境中含量最高的有毒重金属之一,严重威胁植物的生长发育、质量、产量和食用安全。为研究地黄蜡酯合成酶基因镉胁迫表达,该文从地黄全长转录组测序数据中鉴定其成员,并用生物信息学技术与qRT-PCR对其编码蛋白质的理化性质、系统进化和保守结构域及其组织表达与镉胁迫表达进行分析。结果表明:(1)鉴定出两个蜡酯合成酶基因RgOATWSD1与RgOATWSD2,其编码蛋白质的长度、理论等电点和相对分子量依次为463 aa与473 aa、8.86与9.34、51.31 kD与52.49 kD,均为不稳定蛋白。(2)二者均具有acyl_WS_DGAT保守域与DUF1298超家族,前者占其氨基酸序列的92.65%～94.50%。(3)二者均定位于内质网中,二级结构以无规卷曲与α螺旋为主; RgOATWSD1为跨膜蛋白,而RgOATWSD2 不是。(4)二者均在地黄根、茎、叶中差异表达。(5)二者表达均受镉胁迫诱导,但其表达变化趋势不同。该研究鉴定了两个镉胁迫应答反应的蜡酯合成酶基因,为地黄RgOATWSD的镉胁迫表达及功能研究奠定了基础。

Abstract:

Plant wax ester synthase catalyzes the synthesis of wax esters from long-chain alcohols and fatty acids, and plays very important roles in plant wax synthesis and some resistances to drought, pathogenic bacteria, ultraviolet radiation, cold and insect invasion and other environmental stresses; cadmium(Cd)is one of the toxic heavy metals with the highest content in environment, and seriously threatens plant growth, development, quality, yield, and plant food safety. In order to explore the Cd stress expressions of wax ester synthase genes in Rehmannia glutinosa, we identified its wax ester synthase genes from its full-length transcriptome sequencing data, analyzed both physiochemical properties, phytogenetic trees and conserved domains with bioinformatics methods, and tissue expressions and Cd stress expressions using qRT-PCR. The results were as follows:(1)Two wax ester synthase genes, named as RgOATWSD1 and RgOATWSD2, were identified, whose coding proteins were unstable hydrophobic proteins with amino acid lengths of 463 aa and 473 aa, isoelectric points of 8.86 and 9.34 and molecular weights of 51.31 kD and 52.49 kD, respectively.(2)Both proteins contained a conserved acyl_WS_DGAT domain and DUF1298 superfamily, in which the former accounted for 92.65% to 94.50% of the amino acid sequence.(3)Both proteins were located in the endoplasmic reticulum and both secondary structures were mainly composed of random coil and α-helix; RgOATWSD2 was not transmembrane protein but RgOATWSD1.(4)Both were differentially expressed in the roots, stems and leaves of R. glutinosa plants.(5)Both expressions were highly responsive to Cd stress, but both expression change trends were different under Cd stress. This study identifies two wax ester synthase genes in response to Cd stress, and lays a foundation for further research on Cd stress expression and other functions of RgOATWSD.