Basis Of Drought Tolerance Research Articles

Assessment of drought tolerance of spring wheat

Under the conditions of climate change, the problem of drought tolerance of agricultural crops is gaining an increasing effect. The lack of moisture remains a limiting factor and leads to a decrease in plant productivity in an arid climate. Therefore, an important direction of modern breeding, and today, is to increase the drought tolerance of plants when creating new varieties. To assess the resistance of plants, various methods are used, including laboratory ones. In physiological assessment, an effective method is to assess drought tolerance at the seedling stage. A deeper analysis is molecular labeling based on the genes that control the trait under study. The article presents the results of studies on the assessment of soft durum wheat samples for resistance to osmotic stress and their molecular screening using marker technology. The purpose of the research is to study and select the selected varieties of spring wheat on the basis of drought tolerance. The selected varieties and lines are recommended as a promising starting material in breeding for drought tolerance.

Differential seedling growth and tolerance indices reflect drought tolerance in cotton

BackgroundCotton production is adversely effected by drought stress. It is exposed to drought stress at various critical growth stages grown under a water scarcity environment. Roots are the sensors of plants; they detect osmotic stress under drought stress and play an important role in plant drought tolerance mechanisms. The seedling stage is very sensitive to drought stress, and it needed to explore the methods and plant characteristics that contribute to drought tolerance in cotton.ResultsInitially, seedlings of 18 genotypes from three Gossypium species: G. hirsutum, G. barbadense, and G. arboreum, were evaluated for various seedling traits under control (NS) and drought stress (DS). Afterward, six genotypes, including two of each species, one tolerant and one susceptible, were identified based on the cumulative drought sensitivity response index (CDSRI). Finally, growth rates (GR) were examined for shoot and root growth parameters under control and DS in experimental hydroponic conditions. A significant variation of drought stress responses was observed across tested genotypes and species. CDSRI allowed here to identify the drought-sensitive and drought-resistant cultivar of each investigated species. Association among root and shoots growth traits disclosed influential effects of enduring the growth under DS. The traits including root length, volume, and root number were the best indicators with significantly higher differential responses in the tolerant genotypes. These root growth traits, coupled with the accumulation of photosynthates and proline, were also the key indicators of the resistance to drought stress.ConclusionTolerant genotypes have advanced growth rates and the capacity to cop with drought stress by encouraging characteristics, including root differential growth traits coupled with physiological traits such as chlorophyll and proline contents. Tolerant and elite genotypes of G. hirsutum were more tolerant of drought stress than obsolete genotypes of G. barbadense and G. arboreum. Identified genotypes have a strong genetic basis of drought tolerance, which can be used in cotton breeding programs.

Sandbur Drought Tolerance Reflects Phenotypic Plasticity Based on the Accumulation of Sugars, Lipids, and Flavonoid Intermediates and the Scavenging of Reactive Oxygen Species in the Root.

The perennial grass Cenchrus spinifex (common sandbur) is an invasive species that grows in arid and semi-arid regions due to its remarkable phenotypic plasticity, which confers the ability to withstand drought and other forms of abiotic stress. Exploring the molecular mechanisms of drought tolerance in common sandbur could lead to the development of new strategies for the protection of natural and agricultural environments from this weed. To determine the molecular basis of drought tolerance in C. spinifex, we used isobaric tags for relative and absolute quantitation (iTRAQ) to identify proteins differing in abundance between roots growing in normal soil and roots subjected to moderate or severe drought stress. The analysis of these proteins revealed that drought tolerance in C. spinifex primarily reflects the modulation of core physiological activities such as protein synthesis, transport and energy utilization as well as the accumulation of flavonoid intermediates and the scavenging of reactive oxygen species. Accordingly, plants subjected to drought stress accumulated sucrose, fatty acids, and ascorbate, shifted their redox potential (as determined by the NADH/NAD ratio), accumulated flavonoid intermediates at the expense of anthocyanins and lignin, and produced less actin, indicating fundamental reorganization of the cytoskeleton. Our results show that C. spinifex responds to drought stress by coordinating multiple metabolic pathways along with other adaptations. It is likely that the underlying metabolic plasticity of this species plays a key role in its invasive success, particularly in semi-arid and arid environments.

Buckwheat selection for resistance to extreme environmental factors

Aim. Based on the usage of samples from the buckwheat genus collection, create and evaluate new source material for drought tolerance, productivity, and quality indicators. Methods. Testing, material evaluation, analysis of plants, yield and grain quality were carried out in accordance with the generally accepted methods of the State variety testing. Results. A laboratory and field assessment of the initial parental forms selected from the collection of the buckwheat genus, involved in hybridization and hybrid combinations based on them based on drought tolerance in the conditions of Podilskyi State Agrarian and Engineering University during 2006–2019 was carried out. It was revealed that the donors for creating new source material on the basis of drought tolerance are the varieties Skorostyhla 86, Smuglianka, Kazanka, Alyonushka, and Veselka. Buckwheat numbers 7/07, 8/07, 2/07, 24/06 have a vegetation period shorter by 5–12 days, drought tolerance 35,4–47,3 % higher, 0,3–0,7 t higher / ha grain yield and high quality indicators compared with the standard Victoria variety. Conclusions. Selected samples with economically valuable traits (7/06, 4/07, 23/06, 5/07, 6/07, 16/07, 15/07, 25/06, 24/06, 22/06) use in breeding programs to create more drought-resistant buckwheat varieties with high yield and grain quality.
 Keywords: buckwheat, selection, drought tolerance, express method, productivity and quality indicators.

Genome-wide transcriptomic analysis of a desert willow, Salix psammophila, reveals the function of hub genes SpMDP1 and SpWRKY33 in drought tolerance

BackgroundDrought is a major environmental constraint to plant growth, development and productivity. Compared with most willows that are generally susceptible to drought, the desert willow Salix psammophila has extraordinary adaptation to drought stress. However, its molecular basis of drought tolerance is still largely unknown.ResultsDuring polyethylene glycol 6000 (PEG 6000)-simulated drought stress, we found that the osmotic adjustment substances were accumulated and the antioxidant enzyme activities were enhanced in S. psammophila roots. A total of 8172 differentially expressed genes were identified in roots of S. psammophila through RNA-Sequencing. Based on K-means clustering, their expression patterns were classified into nine clusters, which were enriched in several stress-related processes including transcriptional regulation, response to various stresses, cell death, etc. Moreover, 672 transcription factors from 45 gene families were differentially expressed under drought stress. Furthermore, a weighted gene co-expression network was constructed, and eight genes were identified as hub genes. We demonstrated the function of two hub genes, magnesium-dependent phosphatase 1 (SpMDP1) and SpWRKY33, through overexpression in Arabidopsis thaliana. Overexpression of the two hub genes enhanced the drought tolerance in transgenic plants, suggesting that the identification of candidate drought tolerance genes in this study was highly efficient and credible.ConclusionsOur study analyzed the physiological and molecular responses to drought stress in S. psammophila, and these results contribute to dissect the mechanism of drought tolerance of S. psammophila and facilitate identification of critical genes involved in drought tolerance for willow breeding.

Differentially Expressed Genes and Enriched Pathways During Drought-Sensitive Period Under Field Conditions in Bread Wheat

Understanding molecular basis of drought tolerance is important for improving wheat adaption to water-deficit environments. Stem elongation stage is a key period for wheat development and determination of potential grain number. In this study, RNA-seq analysis was conducted to study the effect of drought on wheat transcriptome changes during early stem elongation stage under field condition. In total, 5776 genes responded to drought at stem elongation stage. Seven pathways were significantly affected by drought, including “phagosome”, “Spliceosome”, “Peroxisome”, “Pentose phosphate pathway”, “Ribosome”, “Cutin, suberine and wax biosynthesis”, and “RNA transport”. Real-time quantitative PCR (RT-qPCR) analysis confirmed the involvement of genes encoding tubulins, 6-phosphogluconate dehydrogenase (PGD6), cuticular wax-associated proteins, and heat shock proteins in drought tolerance under multiple genetic backgrounds. Ongoing functional analyses of candidate genes will assist unraveling their biological roles in drought tolerance in wheat.

Proteomic prospects for tolerance of sunflower (Helianthus annuus) to drought stress during the flowering stage

In order to understanding proteomic basis of drought tolerance in sunflower (Helianthus annuus L.), two contrasting inbred lines were subjected to drought stress during the flowering stage for two years. Proteins were extracted from leaves of well-watered and drought-treated plants by using the TCA–acetone precipitation method and analysed by two-dimensional polyacrylamide gel electrophoresis followed by nanoscale liquid chromatography coupled to tandem mass spectrometry for identification of affected proteins. When comparing proteomic patterns, 18 proteins were changed by drought stress in sensitive lines and 24 proteins in tolerant lines. Concurrent down-expressions of oxygen-evolving enhancer and ferredoxin-NADP reductase were considered as primary drought sensors that mediate downstream pathways to cope with drought conditions. Differential and line-specific proteomic changes were attributed as the source for contrasting response to drought stress. According to the results, scavenging of reactive oxygen species, conservation of energy and water, and cell-structure integrity constituted the major aspects of drought tolerance in sunflower.