Ammar Megahed H, Khan Altaf M, Migdadi Hussein M, Abdelkhalek Samah M, Alghamdi Salem S
Legume Research Group, Plant Production Department, Faculty of Food and Agricultural Sciences, King Saud University, P.O. Box 2460, Riyadh 11451, Saudi Arabia; Rice Research and Training Center, Sakha, 33717 KafrEl-Sheikh, Egypt.
Legume Research Group, Plant Production Department, Faculty of Food and Agricultural Sciences, King Saud University, P.O. Box 2460, Riyadh 11451, Saudi Arabia.
Saudi J Biol Sci. 2017 Jan;24(1):80-89. doi: 10.1016/j.sjbs.2016.05.011. Epub 2016 May 25.
This study was carried out to identify drought-responsive genes in a drought tolerant faba bean variety (Hassawi 2) using a suppressive subtraction hybridization approach (SSH). A total of 913 differentially expressed clones were sequenced from a differential cDNA library that resulted in a total of 225 differentially expressed ESTs. The genes of mitochondrial and chloroplast origin were removed, and the remaining 137 EST sequences were submitted to the gene bank EST database (LIBEST_028448). A sequence analysis identified 35 potentially drought stress-related ESTs that regulate ion channels, kinases, and energy production and utilization and transcription factors. Quantitative PCR on Hassawi 2 genotype confirmed that more than 65% of selected drought-responsive genes were drought-related. Among these induced genes, the expression levels of eight highly up-regulated unigenes were further analyzed across 38 selected faba bean genotypes that differ in their drought tolerance levels. These unigenes included ribulose 1,5-bisphosphate carboxylase (rbcL) gene, non-LTR retroelement reverse related, probable cyclic nucleotide-gated ion channel, polyubiquitin, potassium channel, calcium-dependent protein kinase and putative respiratory burst oxidase-like protein C and a novel unigene. The expression patterns of these unigenes were variable across 38 genotypes however, it was found to be very high in tolerant genotype. The up-regulation of these unigenes in majority of tolerant genotypes suggests their possible role in drought tolerance. The identification of possible drought responsive candidate genes in reported here is an important step toward the development of drought-tolerant genotypes that can cope with arid environments.
本研究采用抑制性消减杂交技术（SSH），旨在鉴定耐旱蚕豆品种（哈萨维2号）中的干旱响应基因。从差异cDNA文库中对总共913个差异表达克隆进行了测序，共得到225个差异表达的EST。去除线粒体和叶绿体来源的基因，将剩余的137个EST序列提交至基因库EST数据库（LIBEST_028448）。序列分析鉴定出35个可能与干旱胁迫相关的EST，这些EST调控离子通道、激酶、能量产生与利用以及转录因子。对哈萨维2号基因型进行定量PCR证实，超过65%的所选干旱响应基因与干旱相关。在这些诱导基因中，进一步分析了38个耐旱水平不同的蚕豆基因型中8个高度上调的单基因的表达水平。这些单基因包括核酮糖-1,5-二磷酸羧化酶（rbcL）基因、非LTR反转录元件逆转相关基因、可能的环核苷酸门控离子通道、多聚泛素、钾通道、钙依赖性蛋白激酶以及假定的呼吸爆发氧化酶样蛋白C和一个新的单基因。这些单基因在38个基因型中的表达模式各不相同，但在耐旱基因型中表达量非常高。这些单基因在大多数耐旱基因型中的上调表明它们可能在耐旱性中发挥作用。本文报道鉴定出的可能的干旱响应候选基因，是朝着培育能够应对干旱环境的耐旱基因型迈出的重要一步。
