Seed-Biopriming of Durum Wheat with Diazotrophic Plant Browth Promoting Bacteria (PGPB) Enhanced Tolerance to Fusarium Head Blight (FHB) and Salinity Stress

Abstract

Background The use of bioinoculants based on plant growth-promoting bacteria (PGPB) to promote plant growth under biotic and abiotic stresses is in full expansion. To our knowledge much work has not been, thus far, done on seed-biopriming of durum wheat for tolerance to biotic and abiotic stresses. In the present work, we report detailed account of the effectiveness a potent bacterial strain with proven plant growth-promoting ability and antimicrobial activity. The isolate was selected following screening of several bacterial strains isolated from halophytes that grow in a coastal saline soil in Tunisia for their role in enhancing durum wheat tolerance to both salinity stress and head blight disease.Results Accordingly, Bacillus strains MA9, MA14, MA17 and MA19 were found to have PGPB characteristics as they produced indole-3-acetic acid, siderophores and lytic enzymes, fixed free atmospheric nitrogen, and solubilized inorganic phosphate, in vitro . The in vivo study that involved in planta inoculation assays under control (25 mM NaCl) and stress (125 mM NaCl) conditions indicated that all PGPB strains significantly ( P < 0.05) increased the total plant length, dry weight, root area, seed weight, nitrogen, protein and total mineral content. On the other hand, strain MA17 reduced Fusarium Head Blight (FHB) disease incidence in wheat explants by 64.5%, showing that the strain has antifungal activity as was also displayed by in vitro inhibition study.Conclusions Both in vitro and in vivo studies showed that MA9, MA14 MA9, MA14, MA17 and MA19 strains were able to play the PGPB role. Yet, biopriming with Bacillus strain MA17 offered the highest bioprotection against FHB, plant growth promotion, and salinity tolerance. Hence, the MA17 strain should further be evaluated under field condition and formulated for commercial production. Besides, the strain could further be evaluated for its potential role in bioprotection and growth promotion of other crop plants. We believe, the strain has potential to significantly contribute to wheat production in the arid and semi-arid region, especially the salt affected Middle Eastern Region, besides its potential role in improving wheat production under biotic and abiotic stresses in other parts of the world.

Biopriming of seed with plant growth-promoting bacteria for improved germination and seedling growth

“…This strain was positive for the production of IAA, ACC deaminase, and siderophores and was a phosphate and zinc solubilizer (Pandey and Gupta, 2020). Brahim et al (2022) demonstrated that Bacillus pumilus MA9 and Virgibacillus halodenitrificans MA14 significantly improved wheat germination rate due to secretion of auxin, solubilization of inorganic phosphate, and ACC deaminase activity.…”

“…Germinating seeds are incessantly exposed to many hazardous factors, including pathogens, resulting in biotic stress (Brahim et al, 2022). The ability to produce siderophores and HCN was demonstrated by 18 and nine out of 33 isolates tested, respectively (Supplementary Table S3).…”

Plant Responses to Abiotic Stresses and Rhizobacterial Biostimulants: Metabolomics and Epigenetics Perspectives

“…The rhizosphere chemistry and the development of plant-rhizomicrobiome interactions are still poorly characterised, however, emerging studies have reported that various PGPR species can pre-condition the plants for augmented defence responses against abiotic stresses [ 160 , 161 , 162 , 163 , 164 ]. The molecular mechanisms underlying the rhizobacteria-related defence priming show that this induced state suggests a reprogramming in the cellular metabolism and regulatory machinery of the plants.…”