Role of microorganisms in alleviation of abiotic stresses for sustainable agriculture.

Abstract

Abiotic stresses affect plants in different ways and are causes of reduction in crop productivity. In order to increase crop productivity it becomes necessary to evolve efficient low-cost technologies for abiotic stress management. Soil microorganisms, surviving in the soil under extreme conditions, have shown great properties, which, if exploited can serve agriculture for increasing and maintaining crop productivity. While it is well established that beneficial soil microorganisms can promote growth and increase productivity through mechanisms such as nutrient mobilization, hormone secretion and disease suppression, it is also becoming increasingly clear that their effects may be more far-reaching. Several studies have reported that soil microorganisms may have mechanisms for alleviation of abiotic stresses in plants such as water and temperature stress, salinity, heavy metals etc. Some of these include tolerance to salinity, drought (Azospirillum sp., Pseudomonas syringae, P. fluorescens, Bacillus sp.) and nutrient deficiency (Bacillus polymyxa, Pseudomonas alacaligenes). Other than bacteria, salinity- and drought-tolerant isolates of Trichoderma harzianum and the effect of other strains of Trichoderma in amelioration of such abiotic stresses have also been reported. Arbuscular mycorrhizal fungi (Glomus mosseae, G. etunicatum, G. intraradices, G. fasciculatum, G. macrocarpum, G. coronatum etc.) help in alleviating abiotic stresses in different crops by enhancing nutrient uptake (phosphorus, nitrogen, magnesium and calcium), biochemical (accumulation of proline, betaines, polyamines, carbohydrates and antioxidants), physiological, molecular and ultra-structural changes. In the present chapter, we attempt an overview of current knowledge on how plant-rhizobacteria, plant-Trichoderma as well as plant-mycorrhiza interactions help in alleviating abiotic stress conditions in different crop systems, which can be used for sustainable agriculture.

Pseudomonas 42P4 and Cellulosimicrobium 60I1 as a sustainable approach to increase growth, development, and productivity in pepper plants

“…These antecedents led us to suggest that inoculation with strain Pseudomonas 42P4 stimulates the synthesis endogenous of (+)-catechin, which might induce a positive response in growth, nitrogen accumulation, enhanced Chl and photosynthetic rate, which leads to a greater accumulation of biomass and an increased yield. Similar results were reported by Chakraborty et al (2015) in tea plants inoculated with Bacillus megaterium.…”

Efficacy of Plant Growth Promoting Rhizobacteria on Mungbean Root and Shoot under Salinity Stress Conditions

“…The application of PGPR B. cerus can mitigate salt stress in mungbean and could improve root and shoot-leaf dry weight 168.75 and 286.29% respectively as compared to treatment without PGPR application as reported by Chakraborty et al, (2011).…”

Effect of silicon application with mycorrhizal inoculation on Brassica juncea cultivated under water stress

“…Moreover, arbuscular mycorrhizal fungi can develop drought-adaptive strategies utilizing radical extra-hyphae and affect plant processes such as photosynthesis, root conductivity and root architecture [ 68 , 69 ]. Arbuscular mycorrhizal fungi -mediated response is a multi-faceted process of drought-responsive gene expression and activation [ 70 ]. These metabolic compounds reduce the osmotic ability and hence leaf water capacity in plants subjected to drought.…”