Specific cotton leaf responses to wounding and treatment with cell-free extracts of Aspergillus flavus

Abstract

When initial true leaves of 1-month postemergence Acala SJ-2 cotton plants were wounded by gentle abrasion, accumulations of ferulic acid (4-hydroxy-3-methoxycinnamic acid) were detected on the 3rd and 4th days after treatment. When similar wounds were immediately treated with cell-free extracts of Aspergillus flavus mycelia, elevated levels of scopoletin (6-methoxy-7-hydroxycoumarin) were produced, beginning 1 day after treatment and continuing for 7 days. Elevated levels of scopoletin were not detected in leaves that were only wounded, and enhanced quantities of ferulic acid were not observed in leaf tissue after wounding and exposure to the fungal extract. Accumulations of these compounds were not apparent in nonwounded controls. The results demonstrate a wound response distinct from the wound – fungal extract reaction.