Mishra Rohit Kumar, Sahu Pramod Kumar, Mishra Vani, Jamal Hafiza, Varma Ajit, Tripathi Swati
Amity Institute of Microbial Technology, Amity University, Noida, India.
Department of Microbiology, Indian Council of Agricultural Research - National Bureau of Agriculturally Important Microorganism, Kushmaur, Mau, Uttar Pradesh, India.
Front Plant Sci. 2023 Apr 20;14:1122347. doi: 10.3389/fpls.2023.1122347. eCollection 2023.
Halotolerant plant growth promoting rhizobacteria (PGPR) are beneficial microorganisms utilized to mitigate the biotic and abiotic stresses in plants. The areas of Sundarban mangroves of West Bengal, India have been reported to be rich in halotolerant microflora, yet major area remains unexplored. The present study, therefore, aims to map down the region-specific native microbial community potent of salt tolerance, plant growth promoting (PGP) activity and antagonistic activity against fungal pathogens. Bacterial samples were isolated from the saline soil of the Sundarban mangroves. A total of 156 bacterial samples were isolated and 20 were screened for their salt tolerance potential. These isolates were characterised using morphological, biochemical, and molecular approaches. Based on 16s rRNA sequencing, they were classified into 4 different genera, including sp. (01 isolate), (01 isolate), (01 isolate), and (17 isolates). The halotolerant isolates which possessed plant growth promoting traits including phosphate, and zinc solubilization, indole acetic acid production, siderophore, and ammonia generation were selected. Further, the effect of two halotolerant isolates GN-5 and JR-12 which showed most prominent PGP activities was evaluated in pea plant under high salinity conditions. The isolates improved survival by promoting germination (36 to 43%) and root-shoot growth and weight of pea plant in comparison to non-inoculated control plants. In a subsequent dual culture confrontation experiment, both these halo-tolerant isolates showed antagonistic activities against the aggressive root rot disease-causing (Tassi) Goid NAIMCC-F-02902. The identified isolates could be used as potential bioagents for saline soils, with potential antagonistic effect on root rot disease. However, further studies at the physiological and molecular level would help to delineate a detail mechanistic understanding of broad-spectrum defence against salinity and potential biotic pathogen.
耐盐促植物生长根际细菌（PGPR）是用于减轻植物生物和非生物胁迫的有益微生物。据报道，印度西孟加拉邦孙德尔本斯红树林地区富含耐盐微生物群落，但主要区域仍未得到充分探索。因此，本研究旨在绘制出具有耐盐性、植物生长促进（PGP）活性以及对真菌病原体具有拮抗活性的区域特异性本地微生物群落图谱。从孙德尔本斯红树林的盐渍土壤中分离细菌样本。共分离出156个细菌样本，并筛选出20个样本检测其耐盐潜力。采用形态学、生物化学和分子方法对这些分离株进行表征。基于16s rRNA测序，它们被分为4个不同的属，包括 属（1株分离株）、 属（1株分离株）、 属（1株分离株）和 属（17株分离株）。选择具有促进植物生长特性的耐盐分离株，这些特性包括磷和锌的溶解、吲哚乙酸的产生、铁载体的生成以及氨的产生。此外，在高盐条件下，对豌豆植株评估了表现出最显著PGP活性的两种耐盐分离株GN-5和JR-12的效果。与未接种的对照植株相比，这些分离株通过促进发芽（36%至43%）以及豌豆植株的根和茎生长与重量增加，提高了植株的存活率。在随后的双培养对峙实验中，这两种耐盐分离株均对引起侵袭性根腐病的 （塔西）戈德NAIMCC-F-02902表现出拮抗活性。所鉴定的分离株可作为盐渍土壤的潜在生物制剂，对根腐病具有潜在的拮抗作用。然而，在生理和分子水平上的进一步研究将有助于详细阐述对盐度和潜在生物病原体的广谱防御机制。
