Halobacteria-Based Biofertilizers: A Promising Alternative for Enhancing Soil Fertility and Crop Productivity under Biotic and Abiotic Stresses—A Review

Abstract

Abiotic and biotic stresses such as salt stress and fungal infections significantly affect plant growth and productivity, leading to reduced crop yield. Traditional methods of managing stress factors, such as developing resistant varieties, chemical fertilizers, and pesticides, have shown limited success in the presence of combined biotic and abiotic stress factors. Halotolerant bacteria found in saline environments have potential as plant promoters under stressful conditions. These microorganisms produce bioactive molecules and plant growth regulators, making them a promising agent for enhancing soil fertility, improving plant resistance to adversities, and increasing crop production. This review highlights the capability of plant-growth-promoting halobacteria (PGPH) to stimulate plant growth in non-saline conditions, strengthen plant tolerance and resistance to biotic and abiotic stressors, and sustain soil fertility. The major attempted points are: (i) the various abiotic and biotic challenges that limit agriculture sustainability and food safety, (ii) the mechanisms employed by PGPH to promote plant tolerance and resistance to both biotic and abiotic stressors, (iii) the important role played by PGPH in the recovery and remediation of agricultural affected soils, and (iv) the concerns and limitations of using PGHB as an innovative approach to boost crop production and food security.

Genome analysis of a halophilic Virgibacillus halodenitrificans ASH15 revealed salt adaptation, plant growth promotion, and isoprenoid biosynthetic machinery

“…Halophilic microorganisms help in the improvement of soil structure, plant salt tolerance, and growth through various mechanisms such as phytohormones production (IAA and ABA), solubilizing the essential nutrients (P, K, and Zn, etc. ), regulating the ethylene level, and inducing systemic resistance (ISR) against the harmful plant pathogens through the production of secondary metabolite/antimicrobial peptides (Arora et al, 2020 ; Masmoudi et al, 2023 ). Additionally, halophilic microorganisms mitigate the salt stress in plants by maintaining high K + /Na + and Ca 2+ and scavenging ROS by regulating the expression of antioxidant enzymes and stress-responsive genes (Sharma et al, 2021 ).…”