Identification of osmotic stress-responsive genes from <i>Leymus mollis</i>, a wild relative of wheat (<i>Triticum aestivum</i> L.)

Abstract

The tolerance of the dune grass Leymus mollis (Triticeae; Poaceae) to various biotic and abiotic stresses makes it a very useful genetic resource for wheat breeding. Wide hybridization between L. mollis and wheat allows the introduction of Leymus chromosomes into the wheat genetic background and facilitates the integration of useful traits into wheat. However, the genetic basis controlling the physiological tolerance of L. mollis to multiple environmental stresses remains largely unexplored. Using suppression subtractive hybridization, we identified 112 osmotic-stress-responsive genes from L. mollis and confirmed their differential expression under osmotic stress. These genes were categorized into 13 functional categories, including cell defense and stress response, transcriptional regulation, signal transduction, biosynthesis of compatible solutes and cell wall metabolism. Representative genes were validated by northern blot and RT-PCR analyses of expression patterns in response to osmotic stress and abscisic acid treatment. The genes identified here represent a useful source of expressed sequence tags (ESTs) for the analysis and identification of Leymus chromosomes introduced into wheat. Furthermore, being highly conserved, genetically associated with osmotic stress tolerance and transferable to wheat, these ESTs provide significant tools for the development of EST-derived molecular markers for introgression of osmotic stress tolerance genes into wheat.

Drought and Heat Differentially Affect XTH Expression and XET Activity and Action in 3-Day-Old Seedlings of Durum Wheat Cultivars with Different Stress Susceptibility

“…XTH15 , and XTH16 ) has been previously reported in early developing leaf tissue of six natural variants of Arabidopsis subjected to mild or severe drought stress by Clauw et al (2015), whereas an up-regulation of XTH coding genes has been reported in the elongation zone of drought-stressed rice roots (Yang et al, 2006), in water-stressed leaves of hot pepper plants ( C. annuum L.; Cho et al, 2006) and in osmotically stressed leaves of Leymus mollis (Trin.) Pilg., a wild relative of wheat (Habora et al, 2012). Further, the expression behavior of OsXET9 was differently affected by drought in the Pei’ai64s rice cultivar depending on tissue and development stage, being up-regulated exclusively in the panicles of heading and flowering stage plants (Dong et al, 2011).…”

Cloning of allene oxide cyclase gene from <i>Leymus mollis</i> and analysis of its expression in wheat–<i>Leymus</i> chromosome addition lines

“…Suppressive-subtractive hybridization was performed according to the method of Diatchenko et al (1996) using a PCR-Select cDNA Subtraction Kit (Clontech, Palo Alto, CA, USA) according to the manufacturer’s instructions. Forward-subtracted sequences were cloned and verified as described previously (Eltayeb Habora et al 2012). …”

“…It is considered to be a potentially very useful genetic resource for wheat breeding (Kishii et al 2003), as it is tolerant to salt and drought stress (McGuire and Dvorak 1981), resistant to various diseases, including scab (Mujeeb-Kazi et al 1983) and powdery mildew (Faith 1983) and highly adaptable to nutrient deprivation and harsh conditions. Recently, to clarify the molecular basis of its high tolerance, we identified AOC among several osmotic stress-responsive genes in L. mollis (Eltayeb Habora et al 2012). In this paper, we report the molecular cloning of a L. mollis allene oxide cyclase gene ( LmAOC ), its localization, gene copy number and its expression patterns under various abiotic stresses (salt, drought, cold and heat stresses) and hormone treatments.…”

Chromosome constitution and origin analysis in three derivatives of Triticum aestivum – Leymus mollis by molecular cytogenetic identification

“…Pilger, which grows mainly along sea coasts and in inland dry areas (Fan et al 2009), is considered to be very useful as a genetic resource for wheat breeding (Kishii et al 2003). Being a valuable genetic resources, L. mollis has some desirable characters, such as a perennial growth habit, strong rhizomes, vigorous growth, a high tillering ability, good fecundity, a high number of seeds per spike (Sigurbjornsson 1960), a high protein content, and good resistance to fungal diseases such as powdery mildew, scab, leaf rust, and stripe rust (Fatih 1983;Mujeeb-Kazi et al 1983;Merker 1992), as well as tolerance to low temperatures, saline and alkaline conditions, and heat and drought stresses (McGuire and Dvôrák 1981;Anamthawat-Jónsson et al 1997;Habora et al 2012;Habora et al 2013).…”

“…Leymus mollis has been used extensively for hybridization with bread wheat and durum wheat, and numerous useful genes, particularly those for stripe rust resistance and drought stress tolerance, have been successfully transferred into wheat (Anamthawat-Jónsson et al 1997;Zhou et al 2001;Lu et al 2005;Shao et al 2007;Song et al 2008;Wang et al 2008;Wang and Wang 2009;Yang et al 2010;Bao et al 2012;Habora et al 2012). Many derivatives have been produced from Triticum aestivum (common wheat) -L. mollis hybrids, such as octoploid amphiploids, hexaploid amphiploids, and an alien substitution line (Fu et al 1993;Wang et al 2000Wang et al , 2013Forsström and Merker 2001;He et al 2010;Yang et al 2010;Zhao et al 2012;Pang et al 2014).…”