Title: Functional assignment to positively selected sites in the core type III effector RipG7 from Ralstonia solanacearum
Authors : Wang, Keke
Remigi, Philippe
Anisimova, Maria
Lonjon, Fabien
Kars, Ilona
Kajava, Andrey
Li, Chien-Hui
Cheng, Chiu-Ping
Vailleau, Fabienne
Genin, Stéphane
Peeters, Nemo
Published in : Molecular Plant Pathology
Volume(Issue) : 17
Issue : 4
Pages : 553
Pages to: 564
Publisher / Ed. Institution : Wiley
Issue Date: 2016
License (according to publishing contract) : Licence according to publishing contract
Type of review: Peer review (Publication)
Language : English
Subjects : LRR; Medicago truncatula; Ralstonia solanacearum; positive selection; Type III effector; Virulence function; Amino acid sequence; Bacterial protein; Genetic complementation test; Medicago truncatula; Molecular model; Site-directed mutagenesis; Mutation; Phylogeny; Plant disease; Ralstonia solanacearum; Amino acid sequence homology; Virulence; Bacterial secretion system; Genetic selection
Subject (DDC) : 570: Biology
580: Plants (Botany)
Abstract: The soil-borne pathogen Ralstonia solanacearum causes bacterial wilt in a broad range of plants. The main virulence determinants of R. solanacearum are the type III secretion system (T3SS) and its associated type III effectors (T3Es), translocated into the host cells. Of the conserved T3Es among R. solanacearum strains, the Fbox protein RipG7 is required for R. solanacearum pathogenesis on Medicago truncatula. In this work, we describe the natural ripG7 variability existing in the R. solanacearum species complex. We show that eight representative ripG7 orthologues have different contributions to pathogenicity on M. truncatula: only ripG7 from Asian or African strains can complement the absence of ripG7 in GMI1000 (Asian reference strain). Nonetheless, RipG7 proteins from American and Indonesian strains can still interact with M. truncatula SKP1-like/MSKa protein, essential for the function of RipG7 in virulence. This indicates that the absence of complementation is most likely a result of the variability in the leucine-rich repeat (LRR) domain of RipG7. We identified 11 sites under positive selection in the LRR domains of RipG7. By studying the functional impact of these 11 sites, we show the contribution of five positively selected sites for the function of RipG7CMR15 in M. truncatula colonization. This work reveals the genetic and functional variation of the essential core T3E RipG7 from R. solanacearum. This analysis is the first of its kind on an essential disease-controlling T3E, and sheds light on the co-evolutionary arms race between the bacterium and its hosts.
Departement: Life Sciences und Facility Management
Organisational Unit: Institute of Applied Simulation (IAS)
Publication type: Article in scientific Journal
DOI : 10.1111/mpp.12302
ISSN: 1464-6722
1364-3703
URI: https://digitalcollection.zhaw.ch/handle/11475/8259
Appears in Collections:Publikationen Life Sciences und Facility Management

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