New Strains Isolated from Rhizosphere for Suppressing Spp. and Enhancing Growth of L.

Rhizobacteria from desert plants can alleviate biotic stress and suppress plant diseases, and consequently can enhance plant growth. Therefore, the current study was performed to isolate and identify -associating rhizobacteria based on their antagonistic activity against species and plant growth-promoting properties. Three bacterial isolates were identified as : LDA-1, LDA-2, and LDA-3. The molecular analysis suggests the biosynthesis of the bacteriocins subtilisin and subtilosin, as well as the lipopeptide iturin, by these strains. In addition, the antagonistic study by dual-culture assay showed a high efficacy of all strains against phytopathogenic fungi (, , , ICADL1, and ICADL2) with inhibition percentages ranging from 43.3 to 83.5% in comparison to the control. Moreover, atomic force microscopy (AFM) analysis showed significant differences in the cell wall topography of the ICADL1 among the treated mycelia and untreated control. As a result, these three strains were used as bioinoculants for cotton seedlings infected by ICADL1 in pot trials, and the results revealed that the bacterial inoculations as an individual or combined with ICADL1 significantly improved cotton root and stem length, lateral roots, indole acetic acid (IAA), and gibberellic acid (GA) contents, as well as increased antioxidants, flavonoids, and phenols in comparison to those obtained from healthy and infected control plants. In conclusion, the three bacterial strains of (i.e., LDA-1, LDA-2, and LDA-3) are considered promising tools as biocontrol agents for and cotton growth promoters, and consequently can be used as bio-ertilizer in sustainable agriculture systems.