Inoculation with Acetobacter diatrophycus increases glucose and fructose content in shoots of Sorghum bicolor (L) Moench.

This work analyzes the effect of inoculation with Acetobacter diazotrophicus and of applications of GA3 and IAA on total carbohydrates, sucrose, glucose and fructose in shoots of Sorghum bicolor.Sorghum seedlings grown in plastic pots with sand-vermiculite were inoculated with pure cultures of A. diazotrophicus strain PAL 5 or sterile water. Two days later, GA3, IAA and a combination of the two hormones were applied to the first leaf of un-inoculated seedlings. After 30 days, shoot samples were extracted with 1% TCA, carbohydrates assessed by phenol reaction, and individual sugars (sucrose, glucose and fructose) neasured by capillary gas chromatography-flame ionization detection (GC-FID). A.diazotrophicus, as well as GA3 and IAA, promoted total carbohydrate accumulation. GA3 was the most effective treatment at 30 pmol plant-1. However, neither the inoculation with the bacterium nor the different concentrations of hormones produced sucrose increase as assessed by GC-FID. Notwithstanding fructose and glucose levels were significantly augmented by A. diazotrophicus as compared to control and GA3 and IAA treatments.