Transcriptional analysis of distant signaling induced by insect elicitors and mechanical wounding in Zea mays

To characterize distant signaling in Zea mays we performed a transcriptional analysis in various regions of a corn seedling after treatment with insect elicitor (IE) and mechanical wounding (MW). The genes tested for accumulation were selected based on their involvement in defense Ribosome Inactivating Protein (RIP), regulation of transcription (MYC7) and signaling allene oxide synthase(AOS). Transcript abundance was measured by semi-quantitative polymerase chain reaction (PCR) at different times and locations after IE, MW, jasmonic acid (JA), jasmonic acid-isoleucine (JA-Ile), glutathione and 12-oxophytodienoic acid(OPDA) treatments, all treatments are related to the defense response either by activating or regulating it. The results showed that RIP and AOS were only induced locally, whereas MYC7 had increased transcript abundance in distant tissues after IE. We concluded that IE induced signaling that affects the whole plant as indicated by the increased abundance of transcription factor MYC7. Genes involved more directly in defense accumulate only where the actual damage occurred. The data also suggests that MYC7 might play a significant role in distant signaling. Further experiments are necessary to characterize the transcriptional activity of this transcription factor.