Suppression of an elicitor-induced oxidative burst reaction in Nicotiana tabacum and Medicago sativa cell cultures by corticrocin but not by mycorradicin

The biological activities of mycorradicin, the major component of the yello w pigment formed in maize and other grasses upon colonization by arbuscular mycorrhizal fungi, and corticrocin from the ectomycorrhizal fungus Piloder ma croceum were analysed in cell cultures of tobacco (Nicotiana tabacum L.) and alfalfa (Medicago sativa L.). Tobacco and alfalfa suspension cell cult ures react to elicitor treatment by alkalinization of the culture medium an d generation of activated oxygen species, the so-called oxidative burst. In the present study, the addition of corticrocin suppressed the elicitor-ind uced oxidative burst reaction but not the alkalinization. The suppression o f the oxidative burst by corticrocin was dose dependent. Mycorradicin in ei ther its methylated or free form had no effect on the oxidative burst or th e alkalinization.