Biochemical and molecular identification of Solanum lycopersicum L. temperature tolerant bacterial endophytes

Abstract

Endophytes are non-pathogenic microorganisms and potential natural bio-inoculant that reside within internal tissues of plant, without causing any apparent symptoms of infection and improve the plant health through acquisition of nutrients. The endophytic bacteria were isolated from the roots of Solanum lycopersicum L. surviving at 45–47 °C in the month of June 2013. On the basis of morphological, biochemical, carbon utilization pattern by Biolog and 16S rRNA gene sequence analysis, the isolates were identified as Rhizobium pusense (MS-1), Bacillus flexus (MS-2), B. cereus (MS-3), Methylophilus flavus (MS-4) and Pseudomonas aeruginosa (MS-5). Most of the endophytic bacterial strains showed plant growth promoting traits activities such as phosphate solubilization, production of IAA, siderophore, ammonia, and nitrate reductase. Carbon sources and other chemicals utilization pattern observed with GEN III microplate of Biolog exhibited strains specific responses. Ten antibiotics discs and 96 wells PM 11C plates were used for their antibiotic sensitivity assay. All the strains were sensitive to chloramphenical, erythromycin, rifampicin, piperacillin, imipenam and gentamycin, while P. aeruginosa (MS-5) was resistant to penicillin, linezolid, and clotrimazole discs. This is first report of M. flavus, a facultative methylotroph as an endophyte of tomato plant. © 2019