RESUMO
BACKGROUND: Barley (H. vulgare L.) is an important cereal crop cultivated across various climates globally. Barley and its ancestor (H. vulgare subsp. spontaneum) are an economically valuable model for genetic research and improvement. Drought, among various abiotic stresses, is a substantial threat to agriculture due to its unpredictable nature and significant impact on crop yield. RESULTS: This study was conducted in both greenhouse and laboratory settings. Prior to the study, wild barley accessions were pre-selected based on their sensitivity or tolerance to drought as determined from fieldwork in the 2020-2021 and 2021-2022 cropping seasons. The effects of three levels of drought stress were evaluated (control, 90-95% field capacity [FC]; mild stress, 50-55% FC; and severe stress, 25-30% FC). Several parameters were assessed, including seedling and root growth, enzymatic activity (CAT, SOD, POD), soluble protein levels, chlorophyll content, carotenoids, abaxial and adaxial stomatal density and dimensions, and relative gene expression of Dhn1, SOD, POD, and CAT. Drought stress significantly increased enzyme activities, especially at 25-30% FC, and more in the tolerant genotype. On the other hand, sensitive genotypes showed a notable increase in stomatal density. Under drought stress, there was a general decline in seedling and root growth, protein content, chlorophyll and carotenoids, and stomatal dimensions. Importantly, gene expression analysis revealed that Dhn1, SOD, POD, and CAT were upregulated under drought, with the highest expression levels observed in the drought-tolerant genotype under severe stress conditions (25-30% FC). CONCLUSIONS: Our investigation highlights the distinct morphological, physiological, biochemical, and gene-expression profiles of drought-resistant and drought-sensitive wild barley genotypes under varying degrees of drought.
Assuntos
Hordeum , Hordeum/genética , Secas , Genótipo , Clorofila/metabolismo , Carotenoides/metabolismo , Expressão Gênica , Superóxido Dismutase/metabolismo , Estresse Fisiológico/genéticaRESUMO
Alien disomic addition lines are valuable genetic resources for breeding programs under wide hybridization. The present study was carried out to identify the chromosome location of ISSR markers and genes controlling seed germination under drought stress in wheat-barley disomic addition lines. Germination experiment was performed at 0, -4 bar and -8 bar levels in a completely randomized design with three replications. The Germination Index, Germination Percentage, Coefficient of Germination Velocity, Mean Germination Time, Mean Germination Daily, and Plantlet Growth Speed were measured. Based on karyotype analysis, the presence of addition chromosomes was confirmed. The IS10 (0.494) and IS15 (0.395) primers showed the greatest polymorphism among the addition lines. The primers amplified most parts of the chromosomes 2H, 3H, and 7H, indicating these ISSR primers are located on these chromosomes. It is also indicated that most of the genes responsible for the seed germination under drought stress are located on chromosomes 4H and 5H.