Abstract
Plant growth-promoting rhizobacteria play a substantial role in plant growth and development under biotic and abiotic stress conditions. However, understanding about the functional role of rhizobacterial strains for wheat growth under salt stress remains largely unknown. Here we investigated the antagonistic bacterial strain Bacillus aryabhattai PM34 inhabiting ACC deaminase and exopolysaccharide producing ability to ameliorate salinity stress in wheat seedlings under in vitro conditions. The strain PM34 was isolated from the potato rhizosphere and screened for different PGP traits comprising nitrogen fixation, potassium, zinc solubilization, indole acetic acid, siderophore, and ammonia production, along with various extracellular enzyme activities. The strain PM34 showed significant tolerance towards both abiotic stresses including salt stress (NaCl 2 M), heavy metal (nickel, 100 ppm, and cadmium, 300 ppm), heat stress (60 °C), and biotic stress through mycelial inhibition of Rhizoctonia solani (43%) and Fusarium solani (41%). The PCR detection of ituC, nifH, and acds genes coding for iturin, nitrogenase, and ACC deaminase enzyme indicated the potential of strain PM34 for plant growth promotion and stress tolerance. In the in vitro experiment, NaCl (2 M) decreased the wheat growth while the inoculation of strain PM34 enhanced the germination% (48%), root length (76%), shoot length (75%), fresh biomass (79%), and dry biomass (87%) over to un-inoculated control under 2M NaCl level. The results of experiments depicted the ability of antagonistic bacterial strain Bacillus aryabhattai PM34 to augment salt stress tolerance when inoculated to wheat plants under saline environment.
Highlights
The objectives of our present research were as follows: (1) To isolate the bacteria equipped with plant growth-promoting traits, salt stress tolerance, and bio-control capacity; (2) to identify the bacterial isolate
The rhizosphere soil samples of potato were collected from potato cultivated in Chitral, Pakistan (35.991119◦ N, 71.557720◦ E) and the strain PM34 was isolated from the rhizosphere soil through serial dilution method [20]
Both fungus Rhizoctonia solani and Fusarium solani were obtained from Crop Disease Research Institute, NARC, Islamabad, Pakistan (33.677113◦ N, 73.139111◦ E)
Summary
Wheat (Triticum aestivum) is one of the widely grown food crops globally with an annual production of 760 million tons in 2019–2020 [1]. It fulfills the nutritional requirements of 21% of the world’s population [2]. Wheat crop encounters various abiotic (e.g., temperature, drought, heavy metals, and salt stress) and biotic (e.g., insect attack, weed, and disease infestation) stresses during the developmental stages. These environmental stresses deteriorate the plant’s major metabolic activities, such as decreased
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