New Bacillus subtilis Strains Isolated from Prosopis glandulosa Rhizosphere for Suppressing Fusarium Spp. and Enhancing Growth of Gossypium hirsutum L.

Abstract

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 Prosopis glandulosa-associating rhizobacteria based on their antagonistic activity against Fusarium species and plant growth-promoting properties. Three bacterial isolates were identified as Bacillus subtilis: 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 B. subtilis strains against phytopathogenic fungi (Fusarium nygamai, F. equisseti, F. solani, F. solani ICADL1, and F. oxysporum 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 F. solani ICADL1 among the treated mycelia and untreated control. As a result, these three B. subtilis strains were used as bioinoculants for cotton seedlings infected by F. solani ICADL1 in pot trials, and the results revealed that the bacterial inoculations as an individual or combined with F. solani ICADL1 significantly improved cotton root and stem length, lateral roots, indole acetic acid (IAA), and gibberellic acid (GA3) 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 B. subtilis (i.e., LDA-1, LDA-2, and LDA-3) are considered promising tools as biocontrol agents for F. solani and cotton growth promoters, and consequently can be used as bio-ertilizer in sustainable agriculture systems.

IAA and ACC deaminase producing-bacteria isolated from the rhizosphere of pineapple plants grown under different abiotic and biotic stresses

“…Interestingly, member of Bacillus has been known as a strong biocontrol agent. Three strains of Bacillus subtilis have been shown to exhibit antagonistic activity against Fusarium in a study concerning cotton plantation [ 88 ]. The inoculation of those bacteria, either individually or in a consortium, has increased antioxidants, phenol, and flavonoid levels, increase stem and root length, promote lateral root formation which might be due to increase in IAA level, and also increase gibberellic acid concentration during the exposure to biotic stress.…”

Isolation and Identification of Bacillus subtilis LY-1 and Its Antifungal and Growth-Promoting Effects

“…Some members of the Bacillus genus have been reported to exhibit strong biocontrol activity against various plant pathogens. For example, Abdelmoteleb et al reported that three strains of B. subtilis (LDA-1, 2, and 3) showed highly antagonistic efficacy against phytopathogenic fungi, with percentage inhibition ranging from 43.3% to 83.5% [ 20 ]. In this regard, the results of the dual-culture assay showed that B. subtilis strain LY-1 has potent antifungal activity against F. oxysporum , F. proliferatum , and F. solani , achieving percentage inhibition values of greater than 73.13%, and this effect was higher and more stable than that of other strains previously reported [ 20 , 21 ].…”

Climate change, its impact on crop production, challenges, and possible solutions

“…The projections predict that climate changes will favor spread of pests and diseases in high-latitude areas (Uleberg et al, 2014). Consequently, negative impacts can be expected due to increased vulnerability of crops to pests and diseases (Pautasso et al, 2012;Abdelmoteleb et al, 2023). The brief descriptions of biotic stresses on crops production are described as under:…”