The TNL gene Rdr1 confers broad-spectrum resistance to Diplocarpon rosae

authored by

Ina Menz, Jannis Straube, Marcus Linde, Thomas Debener

Abstract

Black spot disease, which is caused by the ascomycete Diplocarpon rosae, is the most severe disease in field-grown roses in temperate regions and has been distributed worldwide, probably together with commercial cultivars. Here, we present data indicating that muRdr1A is the active Rdr1 gene, a single-dominant TIR-NBS-LRR (Toll/interleukin-1 receptor-nucleotide binding site-leucine rich repeat) (TNL)-type resistance gene against black spot disease, which acts against a broad range of pathogenic isolates independent of the genetic background of the host genotype. Molecular analyses revealed that, compared with the original donor genotype, the multiple integrations that are found in the primary transgenic clone segregate into different integration patterns in its sexual progeny and do not show any sign of overexpression. Rdr1 provides resistance to 13 different single-spore isolates belonging to six different races and broad field mixtures of conidia; thus far, Rdr1 is only overcome by two races. The expression of muRdr1A, the active Rdr1 gene, leads to interaction patterns that are identical in the transgenic clones and the non-transgenic original donor genotype. This finding indicates that the interacting avirulence (Avr) factor on the pathogen side must be widespread among the pathogen populations and may have a central function in the rose–black spot interaction. Therefore, the Rdr1 gene, pyramided with only a few other R genes by sexual crosses, might be useful for breeding roses that are resistant to black spot because the spread of new pathogenic races of the fungus appears to be slow.

Organisation(s)

Institute of Plant Genetics

Type

Article

Journal

Molecular plant pathology

Volume

19

Pages

1104-1113

No. of pages

10

ISSN

1464-6722

Publication date

10.04.2018

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

Molecular Biology, Agronomy and Crop Science, Soil Science, Plant Science

Electronic version(s)

https://doi.org/10.1111/mpp.12589 (Access: Open)