Rapid identification of the Leptosphaeria maculans avirulence gene AvrLm2 using an intraspecific comparative genomics approach. (29th January 2015)

• Record Type: Journal Article
• Authors: Ghanbarnia, Kaveh; Fudal, Isabelle; Larkan, Nicholas J.; Links, Matthew G.; Balesdent, Marie‐Hélène; Profotova, Bronislava; Fernando, W. G. Dilantha; Rouxel, Thierry; Borhan, M. Hossein
• Is Part Of: Molecular plant pathology. Volume 16:Number 7(2015:Sep.)
• Page Start: 699
• Page End: 709
• Publication Date: 2015-01-29
• Subjects: Plant diseases -- Molecular aspects -- Periodicals; Plant-pathogen relationships -- Molecular aspects -- Periodicals; 571.936
• DOI: 10.1111/mpp.12228
• Languages: English
• ISSNs: 1464-6722

Abstract

<abstract abstract-type="main"> <title>Summary</title> <p>Five avirulence genes from <italic>Leptosphaeria maculans</italic>, the causal agent of blackleg of canola (<italic>Brassica napus</italic>), have been identified previously through map‐based cloning. In this study, a comparative genomic approach was used to clone the previously mapped <italic>AvrLm2</italic>. Given the lack of a presence–absence gene polymorphism coincident with the <italic>AvrLm2</italic> phenotype, 36 <italic>L. maculans</italic> isolates were resequenced and analysed for single‐nucleotide polymorphisms (SNPs) in predicted small secreted protein‐encoding genes present within the map interval. Three SNPs coincident with the <italic>AvrLm2</italic> phenotype were identified within <italic>LmCys1</italic>, previously identified as a putative effector‐coding gene. Complementation of a virulent isolate with <italic>LmCys1</italic>, as the candidate <italic>AvrLm2</italic> allele, restored the avirulent phenotype on <italic>Rlm2</italic>‐containing <italic>B. napus</italic> lines. <italic>AvrLm2</italic> encodes a small cysteine‐rich protein with low similarity to other proteins in the public databases. Unlike other avirulence genes, <italic>AvrLm2</italic> resides in a small GC island within an AT‐rich isochore of the genome, and was never found to be deleted completely in virulent isolates.</p> </abstract>