Division of Soil Science, ICAR-Indian Institute of Rice Research, Hyderabad, 500 030, India.
Division of Microbiology, ICAR-Indian Agricultural Research Institute, New Delhi, 110 012, India.
Plant Physiol Biochem. 2019 Oct;143:19-28. doi: 10.1016/j.plaphy.2019.08.018. Epub 2019 Aug 26.
Response of drought susceptible (DS) genotype Pusa Karishma LES-39 and drought tolerant (DT) mustard genotype NPJ-124, to rhizobacterial inoculation under water deficit stress, was compared in the present study to determine the influence of inoculants on biochemical and physiological attributes of these two different genotypes. Inoculation was observed to improve root and shoot dry weight in both the genotypes, although better results were observed in the DS genotype. There was variation in the response of the two genotypes to rhizobacterial inoculation, under water deficit stress. Significant improvement in most of the physiological and biochemical parameters including antioxidative enzyme activities of the DS genotype; with concomitant decrease in starch content, accumulation of HO and lipid peroxidation upon inoculation of rhizobacteria was observed. In contrast, there was improvement in only few physiological and biochemical parameters in the DT genotype in response to inoculation with rhizobacteria. There was significant increase in catalase enzyme activity along with concomitant decrease in lipid peroxidation. Thus, drought susceptibility of the mustard genotypes, NPJ-124 and Pusa Karishma LES-39, determined their physiological, biochemical and antioxidative responses to rhizobacterial inoculation under water deficit stress. Expression of drought stress responsive genes belonging to ABA-dependent (RD20 and RD26) and ABA-independent (DREB2 and DREB1-2) pathways was studied in the DS genotype. Expression of DREB2 and DREB1-2 genes was considerably enhanced due to inoculation under water deficit stress; indicating that in Bacillus-mediated priming for drought stress tolerance, in this genotype, ABA-independent pathway probably played key role in enhancing tolerance to drought stress.
在本研究中，比较了对干旱敏感（DS）基因型 Pusa Karishma LES-39 和耐旱（DT）芥菜基因型 NPJ-124 在水分亏缺胁迫下根际细菌接种的反应，以确定接种对这两种不同基因型的生化和生理特性的影响。接种观察到在两种基因型中均提高了根和茎的干重，尽管在 DS 基因型中观察到更好的结果。在水分亏缺胁迫下，两种基因型对根际细菌接种的反应存在差异。DS 基因型的大多数生理和生化参数（包括抗氧化酶活性）均有显著改善；同时观察到接种根际细菌后淀粉含量、HO 积累和脂质过氧化的减少。相比之下，在 DT 基因型中，只有少数生理和生化参数对根际细菌接种有反应。过氧化氢酶活性显著增加，同时脂质过氧化减少。因此，芥菜基因型 NPJ-124 和 Pusa Karishma LES-39 的干旱敏感性决定了它们对水分亏缺胁迫下根际细菌接种的生理、生化和抗氧化反应。研究了属于 ABA 依赖型（RD20 和 RD26）和 ABA 非依赖型（DREB2 和 DREB1-2）途径的干旱胁迫响应基因在 DS 基因型中的表达。在水分亏缺胁迫下，DREB2 和 DREB1-2 基因的表达显著增强；表明在芽孢杆菌介导的干旱胁迫耐受引发中，在这种基因型中，ABA 非依赖型途径可能在增强对干旱胁迫的耐受性方面发挥关键作用。
