Abdelmoghny A M, Raghavendra K P, Sheeba J Annie, Santosh H B, Meshram Jayant H, Singh Suman Bala, Kranthi K R, Waghmare V N
Cotton Research Institute (CRI), Agricultural Research Center (ARC), Giza, Egypt.
ICAR - Central Institute for Cotton Research (CICR), Nagpur, India.
Physiol Mol Biol Plants. 2020 Dec;26(12):2339-2353. doi: 10.1007/s12298-020-00890-3. Epub 2020 Dec 4.
Drought stress is one of the major abiotic stresses affecting lint yield and fibre quality in cotton. With increase in population, degrading natural resources and frequent drought occurrences, development of high yielding, drought tolerant cotton cultivars is critical for sustainable cotton production across countries. Six genotypes identified for drought tolerance, wider adaptability and better fibre quality traits were characterized for various morpho-physiological and biochemical characters and their molecular basis was investigated under drought stress. Under drought conditions, genotypes revealed statistically significant differences for all the morpho-physiological and biochemical traits. The interaction (genotype × treatment) effects were highly significant for root length, excised leaf water loss and cell membrane thermostability indicating differential interaction of genotypes under control and stress conditions. Correlation studies revealed that under drought stress, relative water content had significant positive correlation with root length and root-to-shoot ratio while it had significant negative correlation with excised leaf water loss, epicuticular wax, proline, potassium and total soluble sugar content. Analysis of expression of fourteen drought stress related genes under water stress indicated that both ABA dependent and ABA independent mechanisms of drought tolerance might be operating differentially in the studied genotypes. IC325280 and LRA5166 exhibited ABA mediated expression of stress responsive genes and traits. Molecular basis of drought tolerance in IC357406, Suraj, IC259637 and CNH 28I genotypes could be attributed to ABA independent pathway. Based on physiological phenotyping, the genotypes IC325280 and IC357406 were identified to possess better root traits and LRA5166 was found to have enhanced cellular level tolerance. Variety Suraj exhibited good osmotic adjustment and better root traits to withstand water stress. The identified drought component trait(s) in specific genotypes would pave way for their pyramiding through marker assisted cotton breeding.
干旱胁迫是影响棉花皮棉产量和纤维品质的主要非生物胁迫之一。随着人口增长、自然资源退化以及干旱频繁发生，培育高产、耐旱的棉花品种对于各国棉花的可持续生产至关重要。对六个鉴定出具有耐旱性、广泛适应性和优良纤维品质性状的基因型进行了各种形态生理和生化特性的表征，并研究了它们在干旱胁迫下的分子基础。在干旱条件下，各基因型在所有形态生理和生化性状上均表现出统计学上的显著差异。根长、离体叶片失水率和细胞膜热稳定性的基因型×处理互作效应极显著，表明在对照和胁迫条件下基因型的互作存在差异。相关性研究表明，在干旱胁迫下，相对含水量与根长和根冠比呈显著正相关，而与离体叶片失水率、表皮蜡质、脯氨酸、钾和总可溶性糖含量呈显著负相关。对水分胁迫下14个干旱胁迫相关基因的表达分析表明，耐旱的ABA依赖和ABA非依赖机制在研究的基因型中可能存在差异作用。IC325280和LRA5166表现出ABA介导的胁迫响应基因和性状的表达。IC357406、Suraj、IC259637和CNH 28I基因型耐旱性的分子基础可能归因于ABA非依赖途径。基于生理表型分析，鉴定出IC325280和IC357406基因型具有较好的根系性状，LRA5166具有增强的细胞水平耐受性。Suraj品种表现出良好的渗透调节能力和较好的根系性状以抵御水分胁迫。在特定基因型中鉴定出的干旱组成性状将为通过标记辅助棉花育种将这些性状聚合奠定基础。
