Plant growth-promoting rhizobacteria (PGPR) represent a set of microorganisms that play significant role in improving plant growth and controlling the phytopathogens. Unpredictable performance after the application of PGPR has been observed when these were shifted from in-vitro to in-vivo conditions due to the prevalence of various abiotic stress conditions. During growing period, the potato crop is subjected to a combination of biotic and abiotic stresses. Rhizoctonia solani, a soil-borne plant pathogen, causes reduced vigor and yield of potato crop worldwide. In the current study, multi-stress-tolerant rhizobacterial strain, Bacillus subtilis PM32, was isolated from field-grown potato with various plant growth promoting (PGP) traits including zinc and potassium solubilization, biological nitrogen fixation, ammonia and siderophore, as well as extracellular enzyme productions (cellulase, catalase, amylase, protease, pectinase, and chitinase). The strain PM32 exhibited a distinct potential to support plant growth by demonstrating production of indole-3-acetic acid (102.6 μM/mL), ACC-deaminase activity (1.63 μM of α-ketobutyrate/h/mg protein), and exopolysaccharides (2.27 mg/mL). By retarding mycelial growth of R. solani the strain PM32 drastically reduced pathogenicity of R. solani. The strain PM32 also suppressed the pathogenic activity significantly by impeding mycelial expansion of R. solani with inhibition co-efficient of 49.87. The B. subtilis PM32 also depicted significant tolerance towards salt, heavy metal (Pb), heat and drought stress. PCR based amplification of ituC and acds genes coding for iturin and ACC-deaminase activity respectively indicated potential of strain PM32 for lipopeptides production and ACC deaminase enzyme activity. Results of both in-vitro and pot experiments under greenhouse conditions depicted the efficiency of B. subtilis PM32 as a promising bio-control agent for R. solani infection together with enhanced growth of potato plants as deciphered from biomass accumulation, chlorophyll a, b, and carotenoid contents. Therefore, it was envisioned that application of indigenous multi-stress tolerant PGPR may serve to induce biotic and abiotic stress tolerance in crops/plants for pathogen control and sustainable global food supply.

植物生长促进根际细菌 (PGPR) 是一组在促进植物生长和控制植物病原体方面发挥重要作用的微生物。由于各种非生物胁迫条件的普遍存在，当这些条件从体外转移到体内条件时，观察到应用 PGPR 后的不可预测的性能。在生长期，马铃薯作物受到生物和非生物胁迫的组合。立枯丝核菌是一种土壤传播的植物病原体，导致全世界马铃薯作物的活力和产量下降。在目前的研究中，耐多胁迫的根际菌株枯草芽孢杆菌PM32 是从田间种植的马铃薯中分离得到的，具有多种植物生长促进 (PGP) 性状，包括锌和钾溶解、生物固氮、氨和铁载体，以及胞外酶产物（纤维素酶、过氧化氢酶、淀粉酶、蛋白酶、果胶酶和几丁质酶）。菌株 PM32 表现出支持植物生长的独特潜力，通过证明产生吲哚-3-乙酸 (102.6 μM/mL)、ACC-脱氨酶活性 (1.63 μM α-酮丁酸/h/mg 蛋白)和胞外多糖 (2.27毫克/毫升）。通过延缓R. solani的菌丝体生长，菌株 PM32 大大降低了R. solani的致病性。PM32菌株还通过阻碍R. solani的菌丝体扩张来显着抑制病原活性抑制系数为 49.87。B. subtilis PM32 还表现出对盐、重金属 (Pb)、热和干旱胁迫的显着耐受性。基于 PCR 的ituC和acds基因的编码 iturin 和 ACC 脱氨酶活性的扩增分别表明菌株 PM32 具有产生脂肽和 ACC 脱氨酶活性的潜力。温室条件下的体外和盆栽实验结果表明，枯草芽孢杆菌PM32 作为一种有前景的抗茄病菌感染生物防治剂的效率，以及从生物量积累、叶绿素a、b、和类胡萝卜素含量。因此，设想应用本地多胁迫耐受性 PGPR 可用于诱导作物/植物对生物和非生物胁迫的耐受性，以控制病原体和可持续的全球粮食供应。