Characterization of Plant Growth-Promoting Bacteria and In Vitro Antagonistic Activity on Root-Knot Nematodes (Meloidogyne spp.)

Abstract

Root-knot nematodes (Meloidogyne spp.) are the most important plant-parasitic nematodes affecting a wide variety of crops. Thus, recent research has been directed at finding microorganisms, including Plant Growth Promoting Rhizobacteria (PGPR), with activity against root-knot nematodes. In this work five potential PGPR were selected from the LEMYB culture collection, which had been isolated from potato and coffee plants in previous work. Five in vitro PGPR features, indol-3-acetic acid (IAA) production, phosphate solubilization, cellulase, protease, and chitinase activity, were tested. Antagonism assays against phytopathogenic fungi and Meloidogyne spp. were performed as well. All studied isolates demonstrated at least one in vitro PGPR ability. Among the five isolates, AZO16M2 was found to be the best producer of IAA and could solubilize bi- and tri-calcium phosphate at all tested temperatures. Additionally, Bac15Mb showed the highest antagonistic activity against Fusarium and Rhizotocnia spp. Root-knot nematode antagonism assays showed that AZO16M2 exhibited the highest nemastatic and nematicidal effect. Data results suggest that these strains could be used in future studies as PGPR and biocontrol agents against Meloidogyne spp. and some phytopathogenic fungi.