Foliar Application of Plant Growth-Promoting Rhizobacteria Increases Antifungal Compounds in Pea (Pisum sativum) Against Erysiphe pisi

Systemic effect of two plant growth-promoting rhizobacterial (PGPR) strains,viz., Pseudomonas fluorescens (Pf4) and P. aeruginosa (Pag), was evaluated on pea (Pisum sativum) against the powdery mildew pathogen Erysiphe pisi. Foliar spray of the two PGPR strains was done on specific nodal leaves of pea and conidial germination of E. pisi was observed on other nodal leaves,distal to the treated ones. Conidial germination was reduced on distant leaves and at the same time,specific as well as total phenolic compounds increased in the leaves distal to those applied with PGPR strains,thereby indicating a positive correlation. The strains induced accumulation of phenolic compounds in pea leaves and the amount increased when such leaves were get inoculated with E. pisi conidia. Between the two strains, Pag was found to be more effective than Pf4 as its effect was more persistent in pea leaves. Foliar application of PGPR strains for the control of powdery mildew of pea is demonstrated in vitro while correlating it with the increased accumulation of plant phenolics.