Differentially expressed genes between drought-tolerant and drought-sensitive barley genotypes in response to drought stress during the reproductive stage

Abstract

Drought tolerance is a key trait for increasing and stabilizing barley productivity in dry areas worldwide. Identification of the genes responsible for drought tolerance in barley (Hordeum vulgare L.) will facilitate understanding of the molecular mechanisms of drought tolerance, and also facilitate the genetic improvement of barley through marker-assisted selection or gene transformation. To monitor the changes in gene expression at the transcriptional level in barley leaves during the reproductive stage under drought conditions, the 22K Affymetrix Barley 1 microarray was used to screen two drought-tolerant barley genotypes, Martin and Hordeum spontaneum 41-1 (HS41-1), and one drought-sensitive genotype Moroc9-75. Seventeen genes were expressed exclusively in the two drought-tolerant genotypes under drought stress, and their encoded proteins may play significant roles in enhancing drought tolerance through controlling stomatal closure via carbon metabolism (NADP malic enzyme, NADP-ME, and pyruvate dehydrogenase, PDH), synthesizing the osmoprotectant glycine-betaine (C-4 sterol methyl oxidase, CSMO), generating protectants against reactive-oxygen-species scavenging (aldehyde dehydrogenase,ALDH, ascorbate-dependent oxidoreductase, ADOR), and stabilizing membranes and proteins (heat-shock protein 17.8, HSP17.8, and dehydrin 3, DHN3). Moreover, 17 genes were abundantly expressed in Martin and HS41-1 compared with Moroc9-75 under both drought and control conditions. These genes were possibly constitutively expressed in drought-tolerant genotypes. Among them, seven known annotated genes might enhance drought tolerance through signalling [such as calcium-dependent protein kinase (CDPK) and membrane steroid binding protein (MSBP)], anti-senescence (G2 pea dark accumulated protein, GDA2), and detoxification (glutathione S-transferase, GST) pathways. In addition, 18 genes, including those encoding Δl-pyrroline-5-carboxylate synthetase (P5CS), protein phosphatase 2C-like protein (PP2C), and several chaperones, were differentially expressed in all genotypes under drought; thus they were more likely to be general drought-responsive genes in barley. These results could provide new insights into further understanding of drought-tolerance mechanisms in barley.

Transcriptional profiling in pearl millet (Pennisetum glaucum L.R. Br.) for identification of differentially expressed drought responsive genes

“…Drought is one of the main environmental constraints to agricultural productivity worldwide. Many efforts have been made to elucidate the mechanisms of drought tolerance in plants through molecular and genomics approaches, and a number of genes that respond to drought stress at the transcriptional level have been reported (Guo et al 2009). Drought limits the agricultural production by preventing the crop plants from expressing their full genetic potential (Mitra 2001).…”

Virus-induced silencing of genes encoding LEA protein in Tibetan hulless barley (Hordeum vulgare ssp. vulgare) and their relationship to drought tolerance

“…The wide ecological range of Tibetan hulless barley differing in water availability, temperature, soil type and vegetation gives it great potential for adaptive diversity to abiotic stresses and serves as a good source of drought-resistance alleles for breeding purposes (Qian et al 2007). Identification of genes responsible for drought tolerance (such as genes encoding late embryogenesis abundant protein, LEA) in Tibetan hulless barley will facilitate the understanding of the molecular mechanisms of drought tolerance, as well as the genetic improvement of crops through marker-assisted selection or gene transformation (Guo et al 2009). …”

Drought Stress-Related Physiological Changes and Histone Modifications in Barley Primary Leaves at HSP17 Gene

“…Although genes that encode histonemodifying enzymes are induced in barley under drought [23,24], how these modifications are distributed in barley, a stress-tolerant crop, is not clear. HSP17 gene was shown to be upregulated in drought-tolerant barley cultivars under water deficit conditions and is involved in drought tolerance in barley [8]. In this study, we report how progressive drought affects physiology, chlorophyll fluorescence, and the expression of HSP17 gene, encoding a heat shock protein, in barley plants grown under greenhouse conditions.…”

“…of reactive oxygen species (ROS) molecules that can cause damage to PSII, DNA, proteins, and membranes [1,2,[5][6][7]. Antioxidant enzymes and protein kinases are activated [1] and several hundred genes e.g., genes encoding transcription factors, dehydrins, osmolytes, chaperones, protein kinases, and phosphatases as well as genes involved in water management, carbon, and antioxidant metabolism, are regulated by drought [2, [8][9][10]. Gene expression is influenced by chromatin structure, which is governed by processes often associated with epigenetic regulation, namely DNA methylation, histone variants, and post-translational histone modifications.…”