Isolation and characterisation of endophytic bacteria present in the leaves of Glycosmis pentaphylla (Retz.) Correa

Abstract

Endophytes are an endosymbiotic group of microorganisms that dwell in plant tissues and are reservoirs of bioactive compounds. However, the researches on this area are limited. The present investigation was undertaken to isolate and characterise endophytic bacteria from the leaves of Glycosmis pentaphylla (Retz.) Correa. An effective surface sterilisation procedure was developed from the experiment to isolate endophytic bacteria from the leaves of the candidate species. There was no bacterial growth observed in the sterility test. A total of 3 endophytic bacteria were isolated from leaves of G. pentaphylla. Isolates showed distinct morphological and biochemical characteristics. Biochemical characterisation of the isolates was performed by following Bergey’s manual of systematic bacteriology. Two isolates were found gram-positive, and one was gram-negative. All three isolates were found positive for the catalase test and negative for the indole test; two isolates (GP-1, GP-3) were positive for the oxidase test; 2 isolates (GP-1, GP-2) were found positive for both citrate and methyl red test. Some plant growth -promoting activities of the isolates were also performed. All the 3 isolates (GP-1, GP-2, and GP-3) were found positive for the ammonia production test; isolate GP-2 was found positive for phosphate solubilisation test; isolate GP-3 was found positive for both IAA production and lipase activity test. The isolated endophytic bacteria survived in different salt concentrations.