Barley endosomal MONENSIN SENSITIVITY1 is a target of the powdery mildew effector CSEP0162 and plays a role in plant immunity. (13th October 2022)

• Record Type: Journal Article
• Authors: Liao, Wenlin; Nielsen, Mads E; Pedersen, Carsten; Xie, Wenjun; Thordal-Christensen, Hans
• Editors: Höfte, Monica
• Is Part Of: Journal of experimental botany. Volume 74:Number 1(2023)
• Page Start: 118
• Page End: 129
• Publication Date: 2022-10-13
• Subjects: Barley powdery mildew -- Blumeria hordei -- effector -- encasement -- Hordeum vulgare -- immunity -- MON1 -- multivesicular body -- pathogen resistance; Botany -- Periodicals; Botany, Experimental -- Periodicals; Plant physiology -- Periodicals; 580
• DOI: 10.1093/jxb/erac403
• Languages: English
• ISSNs: 0022-0957

Abstract

Abstract: Encasements formed around haustoria and biotrophic hyphae as well as hypersensitive reaction (HR) cell death are essential plant immune responses to filamentous pathogens. In this study we examine the components that may contribute to the absence of these responses in susceptible barley attacked by the powdery mildew fungus. We find that the effector CSEP0162 from this pathogen targets plant MONENSIN SENSITIVITY1 (MON1), which is important for the fusion of multivesicular bodies to their target membranes. Overexpression of CSEP0162 and silencing of barley MON1 both inhibit encasement formation. We find that the Arabidopsis ecotype No-0 has resistance to powdery mildew, and that this is partially dependent on MON1. Surprisingly, we find the MON1-dependent resistance in No-0 not only includes an encasement response, but also an effective HR. Similarly, silencing of MON1 in barley also blocks Mla3 -mediated HR-based powdery mildew resistance. Our results indicate that MON1 is a vital plant immunity component, and we speculate that the barley powdery mildew fungus introduces the effector CSEP0162 to target MON1 and hence reduce encasement formation and HR. Abstract : MON1 is essential for activation of Rab7-like GTPases and it is targeted by the barley powdery mildew effector CSEP0162, thus giving it an important role in plant immunity.