Gene expression analysis in the roots of salt-stressed wheat and the cytogenetic derivatives of wheat combined with the salt-tolerant wheatgrass, Lophopyrum elongatum

Abstract

Using microarray analysis, we identified regulatory and signaling-related genes with differential expression in three genotypes with varying degrees of salt tolerance, Triticum aestivum , the amphiploid, and the wheat substitution line DS3E(3A). Lophopyrum elongatum is among one of the most salt-tolerant members of the Triticeae; important genetic stocks developed from crosses between wheat and L. elongatum provide a unique opportunity to compare gene expression in response to salt stress between these highly related species. The octaploid amphiploid contains the entire genome of T. aestivum and L. elongatum, and the disomic substitution line DS3E(3A) has chromosome 3A of wheat replaced by chromosome 3E of L. elongatum. In this study, microarray analysis was used to characterize gene expression profiles in the roots of three genotypes, Triticum aestivum, the octaploid amphiploid, and the wheat DS3E(3A) substitution line, in response to salt stress. We first examined changes in gene expression in wheat over a time course of 3 days of salt stress, and then compared changes in gene expression in wheat, the T. aestivum × L. elongatum amphiploid, and in the DS3E(3A) substitution line after 3 days of salt stress. In the time course experiment, 237 genes had 1.5 fold or greater change at least one out of three time points assayed in the experiment. The comparison between the three genotypes revealed 304 genes with significant differences in changes of expression between the genotypes. Forty-two of these genes had at least a twofold change in expression in response to salt treatment; 18 of these genes have signaling or regulatory function. Genes with significant differences in induction or repression between genotypes included transcription factors, protein kinases, ubiquitin ligases and genes related to phospholipid signaling.

Development and Validation of Thinopyrum elongatum–Expressed Molecular Markers Specific for the Long Arm of Chromosome 7E

“…M any accessions of tall wheatgrass Thinopyrum elongatum (Host) D.R. Dewey (also called Lophopyrum elongatum, Agropyron elongatum and Elytrigia elongatum ) (2 n = 14, EE genome) tolerate many abiotic and biotic stresses (Sharma et al, 1989; Taeb et al, 1993; Friebe et al, 1996; Bai and Shaner, 2004; Lammer et al, 2004; Shen et al, 2004; Colmer et al, 2006; Garg et al, 2009; Hussein et al, 2014). Since the last century, successful crosses of E‐genome‐containing species with wheat ( Triticum aestivum L.) have facilitated the transfer of desired traits and genes to wheat for genetic improvement (Dvořák and Knott, 1974; Mujeeb‐Kazi et al, 2008; Wang, 2011).…”

“…Up to now, Th. elongatum has been used as a donor to transfer genes to bread wheat for improvement of seed quality (Lammer et al, 2004; Garg et al, 2009) as well as resistance to different stresses, including salinity (Colmer et al, 2006; Hussein et al, 2014), waterlogging (Taeb et al, 1993), and diseases such as barley yellow dwarf, leaf rust, and Fusarium head blight (FHB) (Sharma et al, 1989; Friebe et al, 1996; Shen et al, 2004; Zhang et al, 2005).…”

Abscisic Acid-Stress-Ripening Genes Involved in Plant Response to High Salinity and Water Deficit in Durum and Common Wheat

“…Assessment of expression variation after long salt exposure (72 h) is very important because it may be useful to discriminate between salt-tolerant and salt-susceptible genotypes. It could reflect the plant’s long-term adaptation to high salt conditions in contrast to the genes responding to the initial shock of increased salt in the growth medium ( Hussein et al, 2014 ).…”

“…The experimental evidence collected in the present study based on Real-Time PCR data, strongly suggests that ASR genes may be key factors influencing wheat adaptability to high salinity and drought. Indeed, microarray analyses carried out on Triticum varieties exhibiting contrasting phenotypes for salt tolerance, indicate that two distinct gene categories take part to plant response to abiotic stresses, acting at different moments: genes expressed under longer stress exposure were hypothesized to reflect a long-term acclimation and plant adaptation to high salt concentration, in contrast to early genes acting only during the initial shock of increased salt concentration in the growth environment ( Hussein et al, 2014 ).…”

Perennial growth and salinity tolerance in wheat × wheatgrass amphiploids varying in the ratio of wheat to wheatgrass genomes

“…Salinity was increased in 50 mM steps every third day until the desired NaCl concentration was reached. Since NaCl reduces the uptake of Ca 2+ , supplemental Ca 2+ in the form of calcium chloride (CaCl 2 ) was added at a ratio of 8.8 NaCl:1 anhydrous CaCl 2 (Hussein et al, 2014). The plants were exposed to the NaCl solution for 5 weeks, at which point each plant was harvested, oven dried for five days at 65°C and weighed.…”