Alleviation of Salt Stress in Wheat Seedlings via Multifunctional Bacillus aryabhattai PM34: An In-Vitro Study

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.

γ-Polyglutamic Acid Production, Biocontrol, and Stress Tolerance: Multifunction of Bacillus subtilis A-5 and the Complete Genome Analysis

“…The application of multifunctional microorganisms is of great importance to the synchronous reduction of chemical fertilizers and pesticides, soil restoration, food security, agricultural productivity, and ecological agriculture development [1]. Microorganisms capable of promoting plant growth as a new fertilizer, as well as controlling pathogens as a novel pesticide, have become an emerging research target worldwide as they have the potential to improve the scientific and technological innovation of green agricultural inputs [2].…”

“…Subsequently, the underlying molecular mechanisms of the multifunctional microbes were further analyzed. Jiang et al [6] found that B. velezensis HG18, a biocontrol and growth-promoting strain at low temperature, possessed genes related to chitin degradation (6), glucanase (2), chitosanase (1), lipopeptide antibacterial substance (fengycin, surfactin) synthesis (2), and bacteriocin (subtilin, bacillolysin) synthesis (2), but had no γ-PGA synthesis gene clusters. The genome of B. velezensis 83 contained 10 secondary metabolite biosynthesis gene clusters related to biocontrol, along with genes related to γ-PGA and indole-3-acetic acid production, which would facilitate plant growth [7].…”

Efficacy of organic-based carrier material for plant beneficial rhizobacteria application in okra under normal and salt-affected soil conditions

“…a precursor of stress ethylene and helps the plants to cope with the salt stress.) activity (Afridi et al, 2019; Mehmood, Khan, et al, 2021). These rhizobacteria associate with the plant roots and help the plants in improving their yield in normal agricultural soil and even in problem soils (metal contaminated soils, nutrient as well as water deficit soils and saline soils) through their stress tolerance mechanisms (Ahmad et al, 2018; Khan et al, 2021; Tahir, Ahmad, et al, 2019; Tahir, Khalid, et al, 2019).…”

“…Among these soils, saline soils are the most abundant and are causing a huge threat to agriculture production. Saline soils are those soils which have toxic salts like Na + , HCO 3 − , and Cl − (Mehmood, Khan, et al, 2021), with electrical conductivity greater than 4 dS m −1 . In Pakistan, 6.3 million hectares of land is salt affected.…”

Molecular mechanisms of plant growth promotion for methylotrophic Bacillus aryabhattai LAD

“…More strains of B. aryabhattai were isolated from various environments including plant roots, and evaluations of this rhizosphere bacteria have revealed promising properties of this Bacillus species for promoting plant growth and improving crop yields thus having attracted plenty of attention from researchers (Bhattacharyya et al, 2017;Park et al, 2017;Ghosh et al, 2018). Mehmood et al (2021) found that B. aryabhattai promoted wheat growth and reduced the effects of salt stress on wheat. However, the mechanism of this rhizobacteria species promoting plant growth remains to be investigated.…”