Several MAMPs, including chitin fragments, enhance AtPep-triggered oxidative burst independently of wounding

Abstract

AtPeps are a family of small peptides in Arabidopsis that are believed to act as endogenous amplifiers of the plant's innate immune response. In our recent study,10 we showed that in Arabidopsis leaf disks, bacterial MAM Ps (microbeassociated molecular patterns) such as the flagellin derived elicitor flg22, greatly enhanced the release of reactive oxygen species (RO S) triggered by a subsequent AtPep-perception. This enhanced RO S production could be a hallmark either of improved local defense or of the initiation of RO S-based systemic signaling. Here, we established a superior RO S detection system based on a new derivative of luminol (L-012). With this sensitive system we were able to show that chitin, too, acts as an enhancer of AtPep-triggered RO S, linking this specific defense response amplification also to the recognition of fungal pathogens. In addition we used the more sensitive RO S assay to transfer the experimental setup from cut leaf disks to unwounded seedlings. Thereby we revealed that wounding is not a prerequisite to enable the MAM P-induced enhancement of the AtPep-triggered ROS response. © 2013 Landes Bioscience.