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

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 phytopathogen-ic 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 mu g/ml to 857.14 +/- 80.50 mu g/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 ex-periments, the extract of A. americana did not show any effect on the germi-nation of wheat seeds. However, it effectively inhibited the contamination of seeds by phytopathogenic fungi during germination and saline condi-tions. Findings of the study revealed that Pseudomonas plecoglissicida and A. americana extract are very promising for the inhibition of phytopatho-genic fungi and the alleviation of salt stress.