Analysis of transcriptional responses in root tissue of bread wheat landrace (Triticum aestivum L.) reveals drought avoidance mechanisms under water scarcity

Abstract

In this study, high-throughput sequencing (RNA-Seq) was utilized to evaluate differential expression of transcripts and their related genes involved in response to terminal drought in root tissues of bread wheat landrace (L-82) and drought-sensitive genotype (Marvdasht). Subsets of 460 differentially expressed genes (DEGs) in drought-tolerant genotype and 236 in drought-sensitive genotype were distinguished and functionally annotated with 105 gene ontology (GO) terms and 77 metabolic pathways. Transcriptome profiling of drought-resistant genotype “L-82” showed up-regulation of genes mostly involved in Oxidation-reduction process, secondary metabolite biosynthesis, abiotic stress response, transferase activity and heat shock proteins. On the other hand, down-regulated genes mostly involved in signaling, oxidation-reduction process, secondary metabolite biosynthesis, auxin-responsive protein and lipid metabolism. We hypothesized that the drought tolerance in “L-82” was a result of avoidance strategies. Up-regulation of genes related to the deeper root system and adequate hydraulic characteristics to allow water uptake under water scarcity confirms our hypothesis. The transcriptomic sequences generated in this study provide information about mechanisms of acclimation to drought in the selected bread wheat landrace, “L-82”, and will help us to unravel the mechanisms underlying the ability of crops to reproduce and keep its productivity even under drought stress.

Variation Among Spring Wheat (Triticum aestivum L.) Genotypes in Response to the Drought Stress. II—Root System Structure

“…Further, a direct role of ABA-dependent WRKY transcription factors was evident from their up-regulation in response to drought stress. The role of WRKY as a regulator of reactive oxygen species and antioxidant accumulation, cellular membrane stability, and altered osmotic adjustment was suggested [59,62,66]. We found, that the important mechanisms of drought sensing by roots were also regulated by hormones.…”

“…Drought stress tolerance as a polygenic trait involves the expression of many sets of genes governing morpho-physiological traits, including root architecture [59][60][61]. The meta-analytical approach and analysis of multiple transcriptomic data have uncovered many transcription regulators and key genes.…”

“…The predominant role was attributed to abscisic acid (ABA), ethylene, auxins, and cytokinins. They are key regulators of complex heat-drought stress genetic networks in wheat [59,61,62,66]. ABA is important for early response to drought stress, but its high content in roots is not beneficial under prolonged and severe stress.…”

Global transcriptome and weighted gene co-expression network analyses of growth-stage-specific and hybrid-cultivar-specific drought stress responses in maize

“…This has immensely contributed to our better understanding of the complex molecular networks involved in adaptation and tolerance to water-deficit stress. RNA-seq technology has also been used in Sorghum bicolor L. [27], wheat [28], Glycine max L. [29], and rice [30]. Resultantly, several genes that respond to drought stress have been identified.…”

Methods for evaluation of wheat breeding material for drought tolerance

“…Вважається, що одним із можливих механізмів адаптації рослин до стресових умов є збільшення геномної нестабільності й, відповідно, розширення генетичного різноманіття [69,89]. Дослідження багатьох авторів показують, що значну роль у процесах адаптації рослин до несприятливих факторів зовнішнього середовища відіграє активування мобільних генетичних елементів і генів, що кодують білки, залучені в адаптивних реакціях [25,53,59,68]. Тож пошук джерел стійкості, маркування й ідентифікація генів, що відповідають за посухостійкість рослин, лежить в основі технології створення нових сортів багатьох сільськогосподарських культур.…”