Arabidopsis Transcription Factor MYB102 Increases Plant Susceptibility to Aphids by Substantial Activation of Ethylene Biosynthesis

Induction of ethylene biosynthesis by aphids increases the susceptibility of several plant species to aphids. Recent studies have indicated that some MYB transcription factors regulate the phloem-based defense against aphid infestation by modulating ethylene (ET) signaling. has previously been shown to be induced by wound signaling and regulate defense response against chewing insects. However, it remains unclear whether takes part in the defense response of plants to aphids. Here, we investigated the function of in the response of to aphid infestation. was primarily expressed in vascular tissues, and its transcription was remarkably induced by green peach aphids (GPA; ). The results of RNA-Sequencing revealed that overexpression of in promoted ET biosynthesis by upregulation of some 1-aminocyclopropane-1-carboxylate synthase (ACS) genes, which are rate-limiting enzymes of the ET-synthetic pathway. Enhanced ET levels led to reduced resistance to GPA. Furthermore, dominant suppression of inhibited aphid-induced increase of ET levels in . In agreement with a negative regulatory role for ET in aphid defense responses, the overexpressing lines were more susceptible to GPA than wild-type (WT) plants. Overexpression of in obviously repressed aphid-induced callose deposition. Conversely, overexpression of failed to increase aphid susceptibility in both the ET-insensitive mutants and plants treated with inhibitors of ET signaling pathways, demonstrating that the ET was critical for promoting aphid performance conferred by overexpression of . Collectively, our findings indicate that the increases host susceptibility to GPA through the ET-dependent signaling pathways.