Submitted to: International Congress of Nematology
Publication Type: Abstract Only
Publication Acceptance Date: April 2, 2002
Publication Date: May 30, 2002
Citation: Meyer, S.L., Roberts, D.P., Nitao, J.K., Chitwood, D.J. 2002. Examination of rhizosphere-associated microbes for production of compounds active against plant-parasitic nematodes. 2002. Nematology 4: 288. Technical Abstract: In vitro studies identified fungi and bacteria that produce compounds active against plant-parasitic nematodes. Assays of fungus culture filtrates were conducted with Heterodera glycines (soybean cyst nematode: SCN) and Meloidogyne incognita (root-knot nematode: RKN). The tested filtrates exhibited a low correlation in activity against SCN compared with activity against RKN. Only 5.1% of the tested isolates produced culture filtrates that strongly inhibited egg hatch of both SCN and RKN (i.e., egg hatch was 40% or less than egg hatch in potato dextrose broth controls), 3.9% strongly inhibited SCN egg hatch only, and 13.4% inhibited RKN egg hatch (but not SCN). Percentages of filtrates that inhibited J2 mobility were 0.8% (affected both SCN and RKN), 0.4% (SCN only), and 1.2% (RKN only). Compounds with broad-spectrum activity can be identified without testing specific nematode taxa, but identification of compounds with more specific activity should be tested against the target nematode. Similar experiments with rhizosphere-inhabiting bacteria and RKN identified isolates producing compounds active against RKN. One filtrate that suppressed egg hatch was selected for further study; size-fractionation of the culture filtrate showed that the active component is larger than >3 KDa in size.