Use of plant growth-promoting rhizobacteria for the biocontrol of root-rot disease complex of chickpea

The effects of Pseudomonas putida, Pseudomonas alcaligenes and a Pseudomonas isolate (Ps28) on the hatching and penetration of Meloidogyne incognita in chickpea (Cicer arietinum) roots were studied. Root colonisation, antifungal activity against Macrophomina phaseolina and the production of siderophores, hydrogen cyanide (HCN) and indole acetic acid (IAA) were also estimated for each bacterial isolate. P. putida had the greatest inhibitory effect on hatching and root penetration of M. incognita followed by P. alcaligenes and Ps28, respectively. Similarly, P. putida colonised roots more effectively than P. alcaligenes or Ps28. In addition, P. putida had the greatest inhibitory effect on M. phaseolina and produced the greatest amounts of siderophores, IAA and HCN compared with P. alcaligenes and Ps28. The effects of these bacterial isolates on plant growth and root-rot disease complex of chickpea caused by M. incognita and M. phaseolina were observed. Plant inoculations with these bacterial isolates increased plant growth and the number of seed pods in diseased plants while reducing galling, nematode multiplication and the root-rot disease index. P. putida caused the greatest reduction in galling and nematode multiplication followed by P. alcaligenes and Ps28, respectively. The present study suggests that P. putida has potential for the biocontrol of root-rot disease complex of chickpea.