Caenorhabditis elegans as bait for isolating promising biocontrol fungi against Meloidogyne incognita from soils across India

Root Knot Nematode, Meloidogyne incognita is the most economically important plant parasitic nematode and biological control using nematophagous fungi has been widely used for its management. To exploit the rich fungal diversity available in nature to identify novel biocontrol species, 81 fungal isolates have been isolated in this study from 17 soil samples collected across different Indian states using Caenorhabditis elegans as bait. Among the various isolated fungi, 28 isolates belonged to nine pathogenic genera ( Curvularia, Fusarium, A sp ergillus, Clado sp orium, Rhizoctonia, Alternaria, Penicillium, Chaetomella and Cunninghamella ) while 53 could be classified under five non-pathogenic genera ( Paecilomyces, Arthrobotrys, Acremonium, Trichoderma and Talaromyces ). All these isolates were evaluated against M. incognita under in vitro conditions. The results showed that seven isolates belonging to five pathogenic genera and 17 isolates belonging to five non-pathogenic genera caused juveniles mortality above 95%. On the another hand, 10 isolates of five pathogenic genera and 13 isolates grouped under four non-pathogenic genera caused juvenile mortality between 85 and 94% and the remaining isolates caused less than 84% mortality. Thus, in the present study, C. elegans as bait is very effective in isolating many novel fungi as some of the species are the first reports. Further, considerable variation in the performance of different isolates within a genus is another interesting finding that signifies the utility of this approach in isolating highly promising strains.