Crop genotype and a novel symbiotic fungus influences the root endophytic colonization potential of plant growth promoting rhizobacteria.

Effect of plant genotype on the root endophytic colonization ability of a plant growth promoting rhizobacteria (PGPR), Pseudomonas striata was undertaken in this study. Use of a lac-Z tagged P. striata strain showed that, it can exist as an endophyte and the plant genotype determines the performance of the inoculated PGPR. The cultivars of Zea mays L. (maize) and Vigna radiata L. (mung bean) tested showed differential affinity to the PGPR (P. striata) as reflected by a significant variation in the root endophytic colonization ability of P. striata. Coinoculation with a novel symbiotic fungus Piriformospora indica was found to stimulate endophytic colonization of P. striata in both maize and mungbean. The root exudates of maize and mungbean cultivars showed variations in the total sugar and amino acid contents. However, no consistent relationship was recorded between the concentrations of these metabolites and endophytic colonization of the added PGPR.