The Arabidopsis thaliana Transcription Factor AtMYB102 Functions in Defense Against the Insect Herbivore Pieris rapae

In Arabidopsis thaliana the R2R3-MYB transcription factor family consists of over 100 members and is implicated in many biological processes, such as plant development, metabolism, senescence, and defense. The R2R3-MYB transcription factor gene AtMYB102 has been shown to respond to salt stress, ABA, JA, and wounding, suggesting that AtMYB102 plays a role in the response of plants to dehydration after wounding. Here, we studied the role of AtMYB102 in the response of A. thaliana to feeding by larvae of the white cabbage butterfly Pieris rapae. A. thaliana reporter lines expressing GUS under control of the AtMYB102 promoter revealed that AtMYB102 is expressed locally at the feeding sites of herbivore- damaged leaves, but not systemically in uninfested plant parts. Knockout AtMYB102 transposon-insertion mutant plants (myb102) allowed a faster development of P. rapae caterpillars than wild-type Col-0 plants. Moreover, the number of caterpillars that had developed into pupae within 14 days was significantly higher on myb102, indicating that in wild-type plants AtMYB102 contributes to basal resistance against P. rapae feeding. Microarray analysis of wild-type Col-0 and AtMYB102 overexpressing 35S:: MYB102 plants revealed a large number of differentially expressed genes. Besides several defense-related genes, a relatively large number of genes is associated with cell wall modifications.