Effect of some Pseudomonas strains and Agave americana L. on wheat germination under salt stress

Abstract

Currently, several efforts focus remedying the problem of agricultural soil salinity using eco-friendly strategies. This study aimed particularly the study of Triticum durum (durum wheat) seeds germination in the presence of Pseudomonas strains and hydro-alcoholic extract of Agave americana L. under saline stress conditions. The preliminary phytochemical screening of A. americana, phylogenetic identification and production of indole-3-acetic acid (IAA) by Pseudomonas strains, in vitro impact of hydro-alcoholic extract and Pseudomonas strains combination on salt stress resistance, preliminary effects of A. americana on Triticum durum germination and phytopathogenic fungi inhibition under salt stress were carried out using corresponding protocols. In in vitro trials, phytochemical screening revealed the richness of A. americana in polyphenols (1014.062±161.017 mM GA equivalent/g FW) and flavonoids (51.065±27.391 mg quercetin equivalent/g FW). The ability of Pseudomonas strains to produce the phytohormone indole-3-acetic acid (IAA) varied from 116.67±8.25 µg/ml to 857.14±80.50 µg/ml. The leaf extract of A. americana is an effective osmoprotectant that improves the resistance of the strain P1 Pseudomonas plecoglissicida to saline stress. In in vivo experiments, the extract of A. americana did not show any effect on the germination of wheat seeds. However, it effectively inhibited the contamination of seeds by phytopathogenic fungi during germination and saline conditions. Findings of the study revealed that Pseudomonas plecoglissicida and A. americana extract are very promising for the inhibition of phytopathogenic fungi and the alleviation of salt stress.