The biocontrol potential of Pseudomonas fluorescens CHA0 against root knot nematode (Meloidogyne javanica) is dependent on the plant species

Abstract

The scope of this research was to elucidate that in addition to selecting the appropriate biocontrol agent (in biological control strategy) or defense inducer (in plant defense induction strategy), the plant species is also important in the success of these two strategies for phytopathogens management. So in this research, the potential of a potent biocontrol agent Pseudomonas fluorescens CHA0 to biocontrol of root-knot nematode, Meloidogyne javanica and bioinduction of plant defense responses was investigated in two different plants (tomato and cucumber) seedlings. Based on the results and also our previous work, nematode disease severity (No. of galls and egg masses/plant and No. of eggs/individual egg mass) on selected cultivars of tomato and cucumber with no significantly differences was similar, but after using P. fluorescens CHA0, nematode disease severity on tomato was significantly less than cucumber plant. Meanwhile, time scale and the level of peroxidase, polyphenol oxidase, (not catalase) activities and H2O2 accumulation in tomato plants were significantly higher than cucumber. These results provided evidences that the ability of P. fluorescens CHA0 to control of Meloidogyne javanica and induction of systemic resistance of tomato and cucumber plants is not the same. Therefore it can be concluded that, the inducible/biocontrol potential of a bioinducer/biocontrol agent in different plants is dependent on the plant species.