Evolution of the EKA family of powdery mildew avirulence-effector genes from the ORF 1 of a LINE retrotransposon

BMC Genomics

Research Article

Soledad Sacristán¹  Pietro D. Spanu²  Hadi Quesneville³  Joelle Amselem⁴  Thomas Wicker⁵  Simone Oberhaensli⁵  Marielle Vigouroux⁶  James K. M. Brown⁶  Pari Skamnioti⁷  Laurence V. Bindschedler⁸ 

[1] Centro de Biotecnología y Genómica de Plantas (UPM-INIA) and E.T.S.I. Agrónomos, Universidad Politécnica de Madrid, Campus de Montegancedo, 28223, Pozuelo de Alarcón, Madrid, Spain;Department of Life Sciences, Imperial College London, London, UK;INRA, UR1164 URGI Unité de Recherche Génomique-Info, Institut National de la Recherche Agronomique de Versailles-Grignon, 78026, Versailles, France;INRA, UR1164 URGI Unité de Recherche Génomique-Info, Institut National de la Recherche Agronomique de Versailles-Grignon, 78026, Versailles, France;INRA, UR1290 BIOGER, Biologie et gestion des risques en agriculture, Campus AgroParisTech, 78850, Thiverval-Grignon, France;Institute of Plant Biology, University of Zurich, Zollikerstrasse 107, 8008, Zurich, Switzerland;John Innes Centre, Norwich Research Park, NR4 7UH, Norwich, UK;Laboratory of Genetics, Department of Biotechnology, Agricultural University of Athens, Iera Odos 75, TK 11855, Athens, Greece;School of Biological Sciences, Royal Holloway University of London, TW20 0EX, Egham, UK;

关键词: Barley;    Powdery mildew;    Blumeria graminis;    Effector;    Retrotransposon;    LINE;    Co-option;   

DOI  :  10.1186/s12864-015-2185-x

 received in 2015-07-25, accepted in 2015-11-03,  发布年份 2015

来源: Springer

【 摘 要 】

BackgroundThe Avrk1 and Avra10 avirulence (AVR) genes encode effectors that increase the pathogenicity of the fungus Blumeria graminis f.sp. hordei (Bgh), the powdery mildew pathogen, in susceptible barley plants. In resistant barley, MLK1 and MLA10 resistance proteins recognize the presence of AVRK1 and AVRA10, eliciting the hypersensitive response typical of gene for gene interactions. Avrk1 and Avra10 have more than 1350 homologues in Bgh genome, forming the EKA (Effectors homologous to Avrk1 and Avra10) gene family.ResultsWe tested the hypothesis that the EKA family originated from degenerate copies of Class I LINE retrotransposons by analysing the EKA family in the genome of Bgh isolate DH14 with bioinformatic tools specially developed for the analysis of Transposable Elements (TE) in genomes. The Class I LINE retrotransposon copies homologous to Avrk1 and Avra10 represent 6.5 % of the Bgh annotated genome and, among them, we identified 293 AVR/effector candidate genes. We also experimentally identified peptides that indicated the translation of several predicted proteins from EKA family members, which had higher relative abundance in haustoria than in hyphae.ConclusionsOur analyses indicate that Avrk1 and Avra10 have evolved from part of the ORF1 gene of Class I LINE retrotransposons. The co-option of Avra10 and Avrk1 as effectors from truncated copies of retrotransposons explains the huge number of homologues in Bgh genome that could act as dynamic reservoirs from which new effector genes may evolve. These data provide further evidence for recruitment of retrotransposons in the evolution of new biological functions.

【 授权许可】

CC BY   
© Amselem et al. 2015