Halotolerant PGPR Stenotrophomonas maltophilia BJ01 Induces Salt Tolerance by Modulating Physiology and Biochemical Activities of Arachis hypogaea.

Ankita Alexander,Avinash Mishra,Vijay K Singh

doi:10.3389/fmicb.2020.568289

Abstract

Arachis hypogaea (Peanut) is one of the most important cash crops grown for food and oil production. Salinity is a major constraint for loss of peanut productivity, and halotolerant plant growth promoting bacteria not only enhance plant-growth but also provide tolerance against salt stress. The potential of halotolerant bacterium Stenotrophomonas maltophilia BJ01 isolated from saline-soil was explored to enhance the growth of peanut plants under salt stress conditions. Interaction of S. maltophilia BJ01 enhances the growth of the peanut plants and protects photosynthetic pigments under salt stress. Lower electrolyte leakage (about 20%), lipid peroxidation (2.1 μmol g–1 Fw), proline (2.9 μg mg–1 Fw) content and H2O2 (55 μmol g–1 Fw) content were observed in plants, co-cultivated with PGPR compared to untreated plants under stress condition. The growth hormone auxin (0.4 mg g–1 Fw) and total amino acid content (0.3 mg g–1 Fw) were enhanced in plants co-cultivated with PGPR under stress conditions. Overall, these results indicate the beneficial effect of S. maltophilia BJ01 on peanut plants under salt (100 mM NaCl) stress conditions. In conclusion, bacterium S. maltophilia BJ01 could be explored further as an efficient PGPR for growing legumes especially peanuts under salt stress conditions. However, a detailed agronomic study would be needed to ascertain its commercial role.

Highlights

Soil salinity adversely affects the system of the plants at the physiological, biochemical, and molecular levels (Roy et al, 2014)
This study aims to assess the plant growth-promoting attributes of a halophytic bacterium, namely S. maltophilia BJ01, and how these affect the growth of peanut plants under salt stress conditions
After the interaction of the PGPR strain, BJ01 with the plant under control condition and stress condition (100 mM NaCl) plant were evaluated for their growth pattern for 14 days

Summary

Introduction

Soil salinity adversely affects the system of the plants at the physiological, biochemical, and molecular levels (Roy et al, 2014). PGPR Imparts Salt-Tolerance in Peanut (Mha) of agricultural land is affected by salt (Arora, 2017). Arid and semiarid regions of the world are more affected by salinity due to inadequate rain and agricultural practices (Glick et al, 2007). Cereals and legumes are the most sensitive to salt. Salt affects the nodulation process and the nitrogen fixation (Ramana et al, 2012). Even 100 mM of salt is enough to inhibit nodule formation (Dardanelli et al, 2009). Salt creates a hindrance in Ca absorption, which in turn affects the growth of roots and root hair, providing an additional mechanism to hinder nodule formation (Bouhmouch et al, 2005). India in particular has been reported to have the second largest peanut production after China (Fabra et al, 2010)

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