title: Faba bean drought responsive gene identification and validation.
abstract: 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 inVicia fabareported here is an important step toward the development of drought-tolerant genotypes that can cope with arid environments.
authors.affiliation: 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.
authors.forename: Megahed H
authors.initials: MH
authors.lastname: Ammar
authors.affiliation: Legume Research Group, Plant Production Department, Faculty of Food and Agricultural Sciences, King Saud University, P.O. Box 2460, Riyadh 11451, Saudi Arabia.
authors.forename: Altaf M
authors.initials: AM
authors.lastname: Khan
authors.affiliation: Legume Research Group, Plant Production Department, Faculty of Food and Agricultural Sciences, King Saud University, P.O. Box 2460, Riyadh 11451, Saudi Arabia.
authors.forename: Hussein M
authors.initials: HM
authors.lastname: Migdadi
authors.affiliation: Botany and Microbiology Department, College of Science, King Saud University, Saudi Arabia; Rice Research and Training Center, Sakha, 33717 KafrEl-Sheikh, Egypt.
authors.forename: Samah M
authors.initials: SM
authors.lastname: Abdelkhalek
authors.affiliation: Legume Research Group, Plant Production Department, Faculty of Food and Agricultural Sciences, King Saud University, P.O. Box 2460, Riyadh 11451, Saudi Arabia.
authors.forename: Salem S
authors.initials: SS
authors.lastname: Alghamdi
keywords: Drought; Drought-responsive genes; Hassawi 2; Suppressive subtraction hybridization; Vicia faba