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Biology and Genetics of Crown Rust Disease in Ryegrasses
Author(s) -
Dracatos P. M.,
Cogan N. O. I.,
Keane P. J.,
Smith K. F.,
Forster J. W.
Publication year - 2010
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci2010.02.0085
Subject(s) - biology , plant disease resistance , genetics , quantitative trait locus , lolium perenne , genetic variation , pathogen , plant disease , gene , botany , perennial plant , microbiology and biotechnology
The most serious foliar disease of perennial ryegrass ( Lolium perenne L.) is crown rust (caused by Puccinia coronata Corda f.sp. lolii Brown). Progress in resistance breeding using recurrent selection has been slow, due to lack of genetic knowledge. Puccinia coronata is a basidiomycete fungus with a complex life‐cycle involving both asexual and sexual reproductive modes. Pathotype variation may exist, but confirmation is complicated by the outbreeding nature of the host grass and consequent intrapopulation diversity. Qualitative and quantitative resistance mechanisms may hence be due to either major resistance genes responding to mixed pathogen populations, or minor (quantitative) resistance genes. Advances in molecular biology have permitted analysis of both host and pathogen genetics. Development of pathogen‐derived simple sequence repeat (SSR) genetic markers allowed detailed analysis of genetic variation, as well as generation of homogenized inoculum for detailed trait‐dissection studies. Multiple genomic regions were identified as containing quantitative trait loci (QTLs) for pathogen resistance, and specific single nucleotide polymorphism (SNP) markers for defense response (DR) and disease resistance (R) genes have been evaluated for QTL co‐location. The current knowledge status of the crown rust pathogen and genetics of host resistance is reviewed, as well as future prospects for facilitated rust resistance breeding.