APPLICATION OF FATTY-ACIDS TO ELICIT LIPOXYGENASE-MEDIATED HOST-PLANTRESISTANCE TO 2-SPOTTED SPIDER-MITES (ACARI, TETRANYCHIDAE) IN PHASEOLUS-VULGARIS L

It has been hypothesized that fatty acid oxidation products from the l ipoxygenase (LOX) pathway can play an important role in plant defense against herbivorous arthropods. Studies were conducted to investigate whether LOX substrate treatment is correlated with defense against spi der mites. Excised leaf tissue from Phaseolus vulgaris L. seedlings wa s treated with several fatty acid substrates of the LOX enzyme complex . Spider mites confined to treated tissue exhibited reduced fecundity relative to untreated controls. The same fatty acid solutions were app lied to intact seedlings and allowed to grow for 7 d. Mites were then individually caged on newly emerged leaves and their fecundity monitor ed for 20 d. Mites on seedlings treated with those fatty acids that ar e LOX substrates exhibited fecundity reductions similar to that report ed previously in bioassay studies where mite resistance was induced by wounding or prior mite feeding. These results suggest that a proposed biochemical basis for this systemically acquired resistance mechanism is probably substrate limited.