Practical use of CMC-amended rhizobial inoculant for Mucuna pruriens cultivation to enhance the growth and protection against Macrophomina phaseolina

Abstract

In many parts of the world Mucuna pruriens is used as an important medicinal, forage and green manure crop. In the present investigation the effect of the addition of CMC in carrier during development of bioformulation on shelflife, plant growth promotive and biocontrol activity against Macrophomina phaseolina was screened taking M. pruriens as a test crop. Ensifer meliloti RMP6^Ery+Kan+ and Bradyrhizobium sp. BMP7^Tet+Kan+ (kanamycin resistance engineered by Tn5 transposon mutagenesis) used in the study showed production of siderophore, IAA, solubilizing phosphate and biocontrol of M. phaseolina. RMP6^Ery+Kan+ also showed ACC deaminase activity. The survival of both the strains in sawdust-based bioformulation was enhanced with an increase in the concentration of CMC from 0 to 1%. At 0% CMC Bradyrhizobium sp. BMP7^Tet+Kan+ showed more increase in nodule number/plant (500.00%) than E. meliloti RMP6^Ery+Kan+ (52.38%), over the control in M. phaseolina-infested soil. There was 185.94% and 59.52% enhancement in nodule number/plant by RMP6^Ery+Kan+ and BMP7^Tet+Kan+ with an increase in the concentration of CMC from 0% to 1% in the bioformulations. However further increase in concentration of CMC did not result in enhancement in survival of either the strains or nodule number/plant.