Date of Award

8-2012

Degree Name

MS in Agriculture - Plant Protection Science

Department

Horticulture and Crop Science

Advisor

J. Wyatt Brown

Abstract

Aloe mites are herbivores of the genus Aloe (ALOACEAE) and are associated with hyperplastic growth in various aloe species, but the biochemistry of this interaction is poorly understood. In an effort to characterize plant defense responses to herbivory in the genus Aloe, a salivary extract was isolated from aloe mites (Aceria aloinis Keifer) and its bioactivity was tested using a hypocotyl elongation assay. Subsequently, Aloe striata plants were treated with jasmonic acid (JA), salicylic acid (SA), and the mite salivary extract. Using water and methanol, compounds of different polarity were extracted from aloe tissues that had been frozen and crushed at 4, 12, and 24h after treatment. Extracts were analyzed by HPLC and three compounds were found. One of these compounds was SA (mean concentration of 4µg/mL), and this is the first time that this aloe species has been found to produce SA. Two additional peaks of unknown identity were observed in JA- and SA-treated plants. These results suggest that A. striata may in fact undergo a JA-mediated change in secondary metabolism as part of a plant defense response.