Occurrences and characterization of endophytic Gluconacetobacter isolated from sugarcane tissues of North Eastern region of India

Abstract

Sugarcane plants including roots were collected from 21 sugarcane growing locations of Golaghat, Dimapur and Jorhat districts of North Eastern region for isolation of endophytic Gluconacetobacter. Based on the nitrogenase activity, only eight isolates were selected for further characterization of Gluconacetobacter. The nitrogenase activity of the isolates ranged in between 12.4 to 72.4 n mole C2H4 h-1 culture-1. The characteristic yellowish surface pellicles were formed on inoculating the selected isolates into semisolid LGI medium and acetic LGI medium. On enumeration in LGI plates, the frequencies of well recognized Gluconacetobacter like colonies ranged in between 0.75 and 7.68 x 105 (cfu g-1 fresh tissue). Colony morphology of the isolates was irregular flat, irregular raised or circular raised yellow colonies of 1-5 mm in diameter. Light brown to brown pigmentation was observed on potato agar plates and light brown pigmentation with clearing of plates was observed on GYC plates. All the isolates exhibited gram negative and shape of the cells were rods. Reactions to extracellular and intracellular enzymes as well as to the various carbon sources by the isolates explained the diversity among them. The IAR profiles of the eight isolates against twelve antibiotics exhibited wide variation in their response to various antibiotics.