海南龙血树4-香豆酸辅酶A连接酶基因的克隆与表达分析

Cloning and Expression Analysis of 4-coumaric Acid Coenzyme A Ligase from Dracaena cambodiana

4-香豆酸辅酶A连接酶(4CL)是苯丙烷代谢途径中的一个关键酶之一,在木质素和类黄酮生物合成中起重要作用。利用前期已获得的转录组数据,克隆了1个海南龙血树4CL基因,命名为Dc4CL1。Dc4CL1全长为2139bp,编码549个氨基酸。Dc4CL1氨基酸序列具有典型的保守序列SSGTTGMPKGV和催化活性中心GEICIRG序列,其等电点为8.98,相对分子质量为59.7kD,不稳定系数为47.60,在分类上属于不稳定性蛋白。进化树分析表明,Dc4CL1属于ClassⅢ类4CL,血竭诱导剂能够诱导Dc4CL1的表达;Dc4CL1对干旱、盐和糖三种胁迫无响应,而对紫外辐射响应积极;龙血树经过茉莉酸(jasmonicacidJA)、脱落酸(abscisicacidABA)、细胞分裂素(6-BA)和油菜素甾醇(brassinosteroidBR)诱导处理可以上调Dc4CL1的表达。本研究将为进一步揭示4CL在海南龙血树类黄酮生物合成和血竭形成中的潜在功能提供帮助。

4-coumaric acid coenzyme A ligase (4CL) is one of the key enzymes in the phenylpropanoid metabolism pathway and plays an important role in the biosynthesis of lignin and flavonoids. Using the previously obtained transcriptome data, a 4CL gene from Dracaena cambodiana named Dc4CL1 was cloned. The full-length cDNA of Dc4CL1 was 2 139 bp and encoded 549 amino acids. Dc4CL1 has the typical conserved sequence SSGTTGMPKGV and the catalytic activity center GEICIRG sequence. The predicted isoelectric point is 8.98 and the relative molecular mass is 59.7 kD. The instability coefficient is 47.60, which belongs to the stable protein in classification. Phylogenetic tree analysis showed that Dc4CL1 belonged to Class Ⅲ 4CL. The expression results showed that dragon's blood inducer could induce the expression of Dc4CL1; Dc4CL1 did not respond to the three stresses of drought, salt and sugar, but responded positively to ultraviolet radiation; the expression of Dc4CL1 showed varying degrees of increase after treatment with jasmonic acid (JA), abscisic acid (ABA), cytokinin (6-BA) and brassinosteroid (BR). This study would be helpful to reveal 4CL potential functions in the biosynthesis and formation of flavonoids from Dracaena cambodiana.