Examining the molecular interaction between potato (Solanum tuberosum) and Colorado potato beetle Leptinotarsa decemlineata

Abstract

Colorado potato beetle (CPB) is a devastating herbivorous pest of solanaceous plants. Despite the economic impact, little is known about the molecular interaction of CPB with these plants. Using an 11 421 expressed sequence tag (EST) potato microarray, we identified 320 genes differentially expressed in potato leaves in response to CPB herbivory. Amongst these were genes putatively encoding proteinase inhibitors along with enzymes of terpenoid, alkaloid, and phenylpropanoid biosynthetic pathways, suggesting the defensive chemistries that constitute potato’s defense against CPB herbivory. Several genes, such as those encoding proteinase inhibitors, represent mechanisms implicated in other plant–herbivory interactions, and could correspond with general defensive chemistry strategies. In other cases, products of the differentially expressed genes may represent taxa-specific defensive chemistry. For example, the presumed alkaloid products of a putative tropinone reductase I are specific to a subset of the Solanaceae. Two herbivory-induced genes, not specific to potato, are implicated in the synthesis of volatiles known to attract CPB predators. Comparison of continuous herbivore attack versus recovery from CPB attack indicates that fewer genes involved in defensive chemistry are induced after continuous feeding than after feeding and recovery, suggesting the plant’s ability to mount a full defense response is enhanced under light versus heavy attack.