Isolation and characterization of culturable endophytic plant growth-promoting Bacillus species from Mentha longifolia L.

Authors: BURAK ALAYLAR

Abstract: Plant growth-promoting bacteria is one of the most popular promising alternative fertilizers for sustainable agriculture. Hence, it is preferred by agriculturalists today due to its nontoxic, eco-friendly, and affordable costs as well as its benefits on agricultural products. Among these microorganisms, Bacillus is a widely known and investigated genus in rhizosphere of plenty of agricultural products. In the current study, endophytic Bacillus strains were isolated from the root, stem, and leaves of healthy Mentha longifolia L. in Palandöken Mountain, Erzurum-Turkey and evaluated their plant growth promoting parameters such as nitrogen fixation, phosphate solubilization, IAA, siderophore, ACC deaminase, HCN production, and ammonia potential. According to the results, 12 Bacillus strains showed multiple plant growth promoting properties (PGPs). Moreover, molecular identification of the potential PGP Bacillus strains was carried out by using PCR with the universal primers for 16S rRNA gene region. These strains were containing 3 Bacillus sp. (ML7, ML17 and ML46), 3 Bacillus simplex (ML12, ML25 and ML43), 2 Bacillus megaterium (ML36, ML61), 1 Bacillus muralis (ML49), 1 Bacillus aryabhattai (ML55), 1 Bacillus pumilus (ML59), and 1 Bacillus toyonensis (ML63). In conclusion, these results demonstrated that endophytic Bacillus species from native medicinal plants have huge potential for being utilized as promising natural plant growthpromoter as biofertilizers, biostimulants, and bioprotectants in sustainable crop production due to their beneficial PGPs.

Keywords: M. longifolia L., endopyhytic bacteria, Bacillus, 16S rRNA, plant growth promoting properties

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