Abstract
Protease inhibitors (PIs) of plants play crucial role in defense response against herbivores. Although tomato (Solanum lycopersicum) has many PIs in the genome, most of these PIs are not characterized for their responsivity to herbivory and for their transcription factors. In this report, we analyzed a group of tomato PIs that was showed to be coexpressed with transcription factors in the microarray data. The PIs were divided into two subgroups, kunitz- and potato protease inhibitor-type, and the expression of one kunitz-type PI has shown to be induced by jasmonate (JA)-treatment. Expression analysis of methyl-JA treated leaves showed that expression of all PIs was induced and that the correlation of expression levels of each PI was high, suggesting a possibility that these PIs respond to herbivory. We further analyzed MYB- and TCP transcription factors that were included in the PI coexpression module, however, induction of these transcription factors was not observed by the Me-JA treatment. Overexpression of the MYB gene in tomato had no obvious effect on the PI expression. Thus, we concluded that these transcription factors are not likely to involve in the PI expression.
