Plant growth-promoting properties of endophytic bacteria isolated from some xerophytic plants distributed in arid regions (Uzbekistan)

Recent advancements in the development of endophytic microorganisms-based stimulants have shown promising potential in various fields. Research on the identification of these endophytic microorganisms has been well reported, however, there are limited studies of these endophytes isolated from plants in arid regions. Thus, isolation and identification of promising microbial endophytes from xerophytic plants is essential in technology development for sustainable agriculture in arid regions. This study aims to identify the endophytic bacteria isolated from Kochia prostrata (L.) Schrad. and Ceratoides eversmanniana (Stschegl. ex I.G.Borshch.) Botsch. & Ikonn. in vertical zones of arid regions of Uzbekistan, and examine their potential plant growth-promoting properties. Using Luria-Bertani (LB) medium, 70 distinct bacterial colony were isolated from the different segments of K. prostrata and C. eversmanniana. These isotypes were screened using NaCl-supplemented LB medium in which nine promising bacterial isolates showed tolerance to 15% NaCl. The nine promising halophytes were subjected to molecular identification using specific primers. The isolates from K. prostrata are identified as Bacillus amyloliquefaciens, Bacillus pumilus, Priestia aryabhattai, Pseudomonas putida, and Priestia endophytica. On the other hand, Priestia megaterium, Pseudomonas putida, Bacillus subtilis and Brevibacillus parabrevis were isolated from C. eversmanniana. The identified isolates also showed significant plant growth-promoting properties (N2-fixation, IAA production, phosphates solubilization, ACC deaminase production, siderophores production) and shows ability to inhibit pathogenic fungal growth. Based on the result, the identified bacterial endophytes can be processed as growth-stimulants and biological control of fungal pathogens in crops in arid regions.