甘蔗(Saccharum spp.hybrids)木菠萝素(Jacalin)基因的克隆及生物信息学分析

Clone and Bioinformatics Analysis of the Jacalin Gene (ScJRL) from Sugarcane (Saccharum spp. hybrids)

木菠萝素(Jacalin)类凝集素(jacalin-related lectins,JRLs)是一类糖结合蛋白,以家族形式存在于植物中并参与各种生物进程,是植物凝集素超家族中的一类新成员。本研究从甘蔗(Saccharum spp.hybrids)叶片全长c DNA文库中克隆了一个甘蔗木菠萝素基因的c DNA全长序列,命名为Sc JRL(Gen Bank登录号为:KT971368)。Sc JRL全长845 bp,开放读码框长444 bp,共编码147个氨基酸。生物信息学分析显示,Sc JRL推导编码的蛋白为稳定亲水性蛋白,分子量为16.15 k D,预测等电点为6.13。采用实时荧光定量PCR技术,对Sc JRL基因在不同浓度以及不同处理时间的非生物胁迫处理下的表达进行了检测。结果显示,Sc JRL基因分别受Me JA(100μmol/L),SA(5 mmol/L)和H2O2(10 mmol/L)的诱导上调表达,且在处理3 h时表达量已达到最高;Sc JRL基因还分别受到ABA(100μmol/L)和Na Cl(250 mmol/L)的抑制而下调表达,且二者呈现出相同的表达模式。此外,不同处理的H2O2均诱导Sc JRL显著上调表达。当采用中等浓度的外源胁迫处理时,Sc JRL对ABA或Na Cl应答趋势的一致性,以及Sc JRL对SA或H2O2应答趋势的一致性,这说明甘蔗Sc JRL基因作为早期响应基因参与了Me JA和SA信号通路介导的甘蔗防御反应。并且该基因经由SA信号通路正向调控参与了甘蔗应答氧化胁迫,在甘蔗应答抗氧化胁迫机制过程中扮演积极的角色。此外,Sc JRL还经由ABA信号通路介导参与了甘蔗应答盐胁迫,且与ABA信号呈正相关。

Jacalin-related lectins(JRLs), a new member of the lectin superfamily, are carbohydrate-binding proteins which comprise a large gene family and are involved in various biological processes. A c DNA sequence of Jacalingene, termed as Sc JRL(Gen Bank Accession number: KT971368) was cloned from the full-length c DNA library of sugarcane lamina of Saccharum spp. hybrids. The full length of the Sc JRL was 845 bp, containing a444 bp open reading frame(ORF) and encoding 147 amino acids. Bioinformatics analysis of its predicted protein revealed that the Sc JRL was a stable hydrophilic protein with the molecular weight of 16.15 k D and p I of 6.13. Real-time fluorescence quantitative PCR(q RT-PCR) was used to measure the expression of Sc JRL, when the ROC22 seedlings were exposed to various stresses at different concentrations and different treatment times. The results indicated that Sc JRL was upregulated after the treatments with Me JA(100 μmol/L), SA(5 mmol/L) and H2O2(10 mmol/L),respectively, and the expression reached a maximal level with in 3 h. On the contrary, Sc JRL was inhibited after the treatments with ABA(100 μmol/L) and Na Cl(250 mmol/L), respectively, and both stresses responses presented a similar expression pattern. Moreover, the expression of Sc JRL were significantly up-regulated in every H2O2 treatments. When processing with different abiotic stresses under medium-concentration, the expression profiles of Sc JRL showed a consistently downward increasing trend in the response to ABA and Na Cl, and showed a consistently upward trend in the response to SA and H2O2. These results revealed that Sc JRL, acting as a primary auxin-responsive gene, was involved in Me JA- and SA- regulated defense responses. Moreover, the gene might play an active role in oxidative stress tolerant, activating by SA-regulated defense responses in sugarcane,Furthermore, positively correlated with the ABA signal, Sc JRL might also involve in ABA-regulated salt stress response in sugarcane.