Abstract：
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.
摘要：
三株革兰氏阴性菌，根瘤菌,是通过γ（γ）辐射随机诱变开发的。对开发的菌株进行了共生关联的增强特征评估，固氮,和三种豆科植物——鹰嘴豆的作物产量，田豆,和印度北部哈里亚纳邦的小扁豆农田。与未接种对照的作物和用本地或商业作物特异性根瘤菌菌株种植的作物相比，用发达突变体处理的作物在植物特征和作物产量方面表现出显着改善。这种改进归因于产生的突变体，MbPrRz1（鹰嘴豆），MbPrRz2（扁豆），和MbPrRz3（在豌豆上）。此外,发现MbPrRz1和MbPrRz2突变体的共培养共生反应在所有三种作物上都更为明显。使用Pearson相关系数进行的统计分析显示，结瘤和植物生物量是作物产量最相关的参数。在发达突变体的有效性中，MbPrRz1对于所有三种测试作物都产生了最好的结果。此外，与拥有本地根瘤菌群落的田地相比，开发的突变体增强了实验田的宏观和微量营养素。这些发育的突变体被进一步遗传表征，主要表达固氮标记，nifH,似乎属于中生根瘤菌（MbPrRz1）和豆科根瘤菌（MbPrRz2和MbPrRz3）。总之,这项研究强调了开发的根瘤菌突变体作为可持续农业有效生物肥料的潜力，展示他们增强共生关系的能力，作物产量，和土壤肥力。
