Department of Botany, Banaras Hindu University, Varanasi, 221005, India.
Department of Biotechnology, Uttaranchal University, Dehradun, 248007, India.
Arch Microbiol. 2021 Apr;203(3):1167-1174. doi: 10.1007/s00203-020-02109-1. Epub 2020 Nov 23.
Chickpea plant root colonizing bacteria Mesorhizobium ciceri Ca181 promotes plant growth and development through symbiotic association with root nodules. The potentially beneficial effects on plants generated due to this bacterium are mineral nutrient solubilization, abiotic stress tolerance, and nitrogen-fixation, though the molecular mechanisms underlying these probiotic capacities are still largely unknown. Hence, this study aims to describe the molecular mechanism of M. ciceri Ca181 in drought stress tolerance and phosphorus solubilization. Here we have developed the transposon inserted mutant library of strain Ca181 and further screened it to identify the phosphorous solubilization and PEG-induced drought stress tolerance defective mutants, respectively. Resultantly, a total of four and three mutants for phosphorous solubilization and drought stress tolerance were screened and identified. Consequently, Southern blot confirmation was done for the cross verification of insertions and stability in the genome. Through the sequencing of each mutant, the interrupted gene was confirmed, and the finding revealed that the production of gluconic acid is necessary for phosphorus solubilization, while otsA, Auc, and Usp genes were involved in the mechanism of drought stress tolerance in M. ciceri Ca181.
鹰嘴豆植物根定殖细菌中慢生根瘤菌 Ca181 通过与根瘤的共生关系促进植物的生长和发育。由于这种细菌，对植物产生了潜在的有益影响，包括矿物养分的溶解、非生物胁迫耐受和固氮，尽管这些益生菌能力的分子机制在很大程度上仍不清楚。因此，本研究旨在描述 M. ciceri Ca181 在干旱胁迫耐受和磷溶解中的分子机制。在这里，我们开发了菌株 Ca181 的转座子插入突变体文库，并进一步对其进行筛选，以分别鉴定出磷溶解和 PEG 诱导的干旱胁迫耐受缺陷突变体。结果，筛选和鉴定了总共 4 个和 3 个用于磷溶解和干旱胁迫耐受的突变体。因此，通过 Southern blot 对插入和基因组稳定性进行了交叉验证。通过对每个突变体的测序，确认了中断的基因，并发现产葡萄糖酸对于磷溶解是必要的，而 otsA、Auc 和 Usp 基因参与了 M. ciceri Ca181 干旱胁迫耐受的机制。
