Burkholderia sp. strain TNAU-1 for biological control of root rot in mung bean (Vigna radiata L.) caused by Macrophomina phaseolina

The potential of Burkholderia sp. strain TNAU-1 for the management of mung bean (Vigna radiata L.) root rot caused by Macrophomina phaseolina was evaluated under greenhouse conditions. Burkholderia sp. strain TNAU-1 inhibited the mycelial growth of M. phaseolina in vitro and produced an inhibition zone of 18.8 mm. Mung bean seeds when treated with the bacterial suspension, showed significant increase in root length, shoot length and seedling vigour. A talc-based powder formulation of Burkholderia sp. strain TNAU-1 was developed and evaluated for its efficacy in the management of mung bean root rot under greenhouse conditions. Seed treatment or soil application of the powder formulation of Burkholderia sp. strain TNAU-1 significantly reduced the incidence of root rot and increased the germination percentage and plant height. Seed treatment with the powder formulation of Burkholderia sp. strain TNAU-1 alone was effective in controlling root rot disease; but the combined seed treatment and soil application of Burkholderia sp. strain TNAU-1, increased the efficacy. Seed treatment and soil application with Burkholderia sp. reduced the root rot incidence from 52.6 per cent (with non-bacterized seeds) to 16.7 per cent. Control of root rot with the application of Burkholderia sp. by seed treatment and soil application was not statistically different from that obtained with seed treatment with carbendazim. The endophytic movement of Burkholderia sp. in the stem, roots and leaves of mung bean was confirmed through PCR using Burkholderia sp. specific primers which resulted in the amplification of a 417 bp product.