Siderophore Producing Aspergillus spp as Bioinoculant for Enhanced Growth of Mung Bean

Abstract

Two fungal species A. niger and A. parasiticus isolated from agriculture field were used in the present study. These two fungal isolates were studied for the siderophore production on the modified CAS agar medium. On daily observation it was observed that the growth was increased along with the production indicating the change in colour of CAS dye from blue to purplish red by A. niger and Yellow by A. parasiticus . Quantitative determination of siderophore production was further studied using liquid medium. After 10 days of incubation A. niger and A. parasiticus produce 80% and 73% units of siderophore. Chemical determination showed that both the fungal isolates showed hydroxamate type of siderophore. Optimization of type of inoculum showed that block inoculum produced maximum siderophore compared to loop and monosporic inoculation in both the fungal isolates. Neutral pH 7.0 showed maximum siderophore production in both the isolates. Decrease in iron concentration increases the siderophore production by the fungal isolates. Maximum siderophore production 80% and 74% units was observed in A. niger and A. parasiticus respectively when there was no addition of iron in the medium. Pot studies were carried out to observe the effect of fungal inoculum on mungbean plant. Inoculation with fungal isolates showed increase in number of leaves, number of branches, number of lateral roots, plant height, fresh weight and dry weight of plant compared to control. Thus both the fungal isolates proved to be potential bioinoculant for improving the growth of mungbean plant.