TY - JOUR T1 - Intra-strain elicitation and suppression of plant immunity by <em>Ralstonia solanacearum</em> type-III effectors in <em>Nicotiana benthamiana</em> JF - bioRxiv DO - 10.1101/780890 SP - 780890 AU - Yuying Sang AU - Wenjia Yu AU - Haiyan Zhuang AU - Yali Wei AU - Lida Derevnina AU - Jiamin Luo AU - Alberto P. Macho Y1 - 2019/01/01 UR - http://biorxiv.org/content/early/2019/09/24/780890.abstract N2 - Effector proteins delivered inside plant cells are powerful weapons for bacterial pathogens, but this exposes the pathogen to potential recognition by the plant immune system. Therefore, effector acquisition must be balanced for a successful infection. Ralstonia solanacearum is an aggressive pathogen with a large repertoire of secreted effectors. One of these effectors, RipE1, is conserved in most R. solanacearum strains sequenced to date. In this work, we found that RipE1 triggers immunity in N. benthamiana, which requires the immune regulator SGT1, but not EDS1 or NRCs. Interestingly, RipE1-triggered immunity induces the accumulation of salicylic acid (SA) and the overexpression of several genes encoding phenylalanine-ammonia lyases (PALs), suggesting that the unconventional PAL-mediated pathway is responsible for the observed SA biosynthesis. Surprisingly, RipE1 recognition also induces the expression of jasmonic acid (JA)-responsive genes and JA biosynthesis, suggesting that both SA and JA may act cooperatively in response to RipE1. Finally, we found that RipE1 expression leads to the accumulation of glutathione in plant cells, which precedes the activation of immune responses. R. solanacearum encodes another effector, RipAY, which is known to inhibit immune responses by degrading cellular glutathione. Accordingly, we show that RipAY inhibits RipE1-triggered immune responses. This work shows a strategy employed by R. solanacearum to counteract the perception of its effector proteins by the plant immune system. ER -