Department of Molecular Biology, Biotechnology and Bioinformatics, CCS Haryana Agricultural University, Hisar, India.
Department of Microbiology, OM Sterling Global University, Hisar, India.
J Basic Microbiol. 2024 Nov;64(11):e2400327. doi: 10.1002/jobm.202400327. Epub 2024 Jul 17.
Three strains of Gram-negative bacterium, Rhizobium, were developed by gamma (γ)-irradiation random mutagenesis. The developed strains were evaluated for their augmented features for symbiotic association, nitrogen fixation, and crop yield of three leguminous plants-chickpea, field-pea, and lentil-in agricultural fields of the northern Indian state of Haryana. Crops treated with developed mutants exhibited significant improvement in plant features and the yield of crops when compared to the control-uninoculated crops and crops grown with indigenous or commercial crop-specific strains of Rhizobium. This improvement was attributed to generated mutants, MbPrRz1 (on chickpea), MbPrRz2 (on lentil), and MbPrRz3 (on field-pea). Additionally, the cocultured symbiotic response of MbPrRz1 and MbPrRz2 mutants was found to be more pronounced on all three crops. The statistical analysis using Pearson's correlation coefficients revealed that nodulation and plant biomass were the most related parameters of crop yield. Among the effectiveness of developed mutants, MbPrRz1 yielded the best results for all three tested crops. Moreover, the developed mutants enhanced macro- and micronutrients of the experimental fields when compared with fields harboring the indigenous rhizobial community. These developed mutants were further genetically characterized, predominantly expressing nitrogen fixation marker, nifH, and appeared to belong to Mesorhizobium ciceri (MbPrRz1) and Rhizobium leguminosarum (both MbPrRz2 and MbPrRz3). In summary, this study highlights the potential of developed Rhizobium mutants as effective biofertilizers for sustainable agriculture, showcasing their ability to enhance symbiotic relationships, crop yield, and soil fertility.
三种革兰氏阴性菌（根瘤菌）通过伽马（γ）射线随机诱变产生。在印度北部哈里亚纳邦的农业田中，对这些产生的菌株进行了评估，以确定它们在共生关系、固氮和三种豆科植物（鹰嘴豆、田豌豆和兵豆）中的产量方面的增强特性。与对照（未接种）作物和种植本地或商业专用根瘤菌的作物相比，用产生的突变体处理的作物在植物特征和作物产量方面都有显著提高。这种改善归因于产生的突变体 MbPrRz1（在鹰嘴豆上）、MbPrRz2（在兵豆上）和 MbPrRz3（在田豌豆上）。此外，还发现 MbPrRz1 和 MbPrRz2 突变体的共生共培养反应在所有三种作物上更为明显。使用皮尔逊相关系数的统计分析表明，结瘤和植物生物量是与作物产量最相关的参数。在产生的突变体的有效性中，MbPrRz1 对所有三种测试的作物都产生了最佳的结果。此外，与含有本地根瘤菌群落的田地相比，产生的突变体增强了实验田地的大量和微量营养素。这些产生的突变体进一步进行了遗传特征分析，主要表达氮固定标记 nifH，并且似乎属于中慢生根瘤菌（MbPrRz1）和根瘤菌（MbPrRz2 和 MbPrRz3）。总之，本研究强调了产生的根瘤菌突变体作为可持续农业有效生物肥料的潜力，展示了它们增强共生关系、作物产量和土壤肥力的能力。
