Effects of metalaxyl on elicitor activity, stimulation of glyceollin production and growth of sensitive and tolerant isolates of Phytophthora megasperma f.sp. glycinea

摘要: Abstract Mutants of Phytophthora megasperma f.sp. glycinea races 1,4 and 6, tolerant to high concentrations metalaxyl (50- > 500 μg ml−1), were isolated from colonies irradiated with ultraviolet light. When these metalaxyl-tolerant isolates used inoculate hypocotyls compatible soybeans treated metalaxyl, a majority caused symptoms typical interactions rapidly spreading lesions low levels glyceollin. This contrasted the restricted brown glyceollin content that developed following inoculation parent (metalaxyl-sensitive) isolates. However, few mutant tolerated ml−1in vitro sensitive (⩽ 10 ml−1) in inoculated plants lesions. Comparisons made release elicitors into culture fluids isolate addition medium. Elicitor activity was increased significantly by treatment but not those isolate. After fractionation gel filtration most elicitor detected fractions corresponding second two carbohydrate peaks. In general, results are consistent possibility infected plants, at marginally inhibitory fungal hyphae may stimulate host-defence responses otherwise interactions.