Comparative genomics of host adaptive traits in Xanthomonas translucens pv. graminis

BMC Genomics

Research Article

Alexander Goesmann¹  Jochen Blom¹  Daniel Wibberg²  Frank-Jörg Vorhölter³  Lena Hersemann⁴  Roland Kölliker⁴  Franco Widmer⁴ 

[1] Bioinformatics and Systems Biology, Justus Liebig University Giessen, 35392, Giessen, Germany;Center for Biotechnology, Bielefeld University, 33615, Bielefeld, Germany;Center for Biotechnology, Bielefeld University, 33615, Bielefeld, Germany;MVZ Dr. Eberhard & Partner Dortmund, 44137, Dortmund, Germany;Molecular Ecology, Agroscope, 8046, Zurich, Switzerland;

关键词: Inter-pathovar comparison;    Type VI secretion system;    LPS O-antigen;    HrpE;    PilA;   

DOI  :  10.1186/s12864-016-3422-7

 received in 2016-07-16, accepted in 2016-12-14,  发布年份 2017

来源: Springer

【 摘 要 】

BackgroundXanthomonas translucens pathovars differ in their individual host ranges among Poaceae. As the causal agent of bacterial wilt in Italian ryegrass (Lolium multiflorum Lam.), X. translucens pv. graminis (Xtg) is one of the most important bacterial pathogens in temperate grassland regions. The genomes of six Xtg strains from Switzerland, Norway, and New Zealand were sequenced in order to gain insight into conserved genomic traits from organisms covering a wide geographical range. Subsequent comparative analysis with previously published genome data of seven non-graminis X. translucens strains including the pathovars arrhenatheri, poae, phlei, cerealis, undulosa, and translucens was conducted to identify candidate genes linked to the host adaptation of Xtg to Italian ryegrass.ResultsPhylogenetic analysis revealed a tight clustering of Xtg strains, which were found to share a large core genome. Conserved genomic traits included a non-canonical type III secretion system (T3SS) and a type IV pilus (T4P), which both revealed distinct primary structures of the pilins when compared to the non-graminis X. translucens strains. Xtg-specific traits that had no homologues in the other X. translucens strains were further found to comprise several hypothetical proteins, a TonB-dependent receptor, transporters, and effector proteins as well as toxin-antitoxin systems and DNA methyltransferases. While a nearly complete flagellar gene cluster was identified in one of the sequenced Xtg strains, phenotypic analysis pointed to swimming-deficiency as a common trait of the pathovar graminis.ConclusionOur study suggests that host adaptation of X. translucens pv. graminis may be conferred by a combination of pathovar-specific effector proteins, regulatory mechanisms, and adapted nutrient acquisition. Sequence deviations of pathogen-associated molecular patterns (PAMPs), as observed for the pilins of the T4P and T3SS, are moreover likely to impede perception by the plant defense machinery and thus facilitate successful host colonization of Italian ryegrass.

【 授权许可】

CC BY   
© The Author(s). 2017