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PMID: 11724938 Published · ppublish English Journal Article Research Support, Non-U.S. Gov't

High frequency mitotic gene conversion in genetic hybrids of the oomycete Phytophthora sojae.

Proceedings of the National Academy of Sciences of the United States of America ·Vol. 98 ·No. 25 ·2001-12-04 ·Pages 14530-5

Chamnanpunt J, Shan WX, Tyler BM

Abstract

Microbial populations depend on genetic variation to respond to novel environmental challenges. Plant pathogens are notorious for their ability to overcome pesticides and host resistance genes as a result of genetic changes. We report here that in particular hybrid strains of Phytophthora sojae, an oomycete pathogen of soybean, high frequency mitotic gene conversion rapidly converts heterozygous loci to homozygosity, resulting in heterokaryons containing highly diverse populations of diploid nuclei. In hybrids involving strain P7076, conversion rates of up to 3 x 10(-2) per locus per nucleus per generation were observed. In other hybrids, rates were of the order of 5 x 10(-5). Independent gene conversion was observed within a selected linkage group including loci as close as 0.7 kb apart and in unlinked markers throughout the genome. Gene conversions continued throughout vegetative growth and were stimulated by further sexual reproduction. At many loci, conversion showed extreme disparity, with one allele always being lost, suggesting that conversion was initiated by allele-specific double-stranded breaks. Pedigree analysis indicated that individual loci undergo multiple independent conversions within the nuclei of a vegetative clone and that conversion may be preceded by a heritable "activation" state.

MeSH Terms
Alleles Chromosome Mapping Gene Conversion Genetic Variation Homozygote Hybridization, Genetic Mitosis/genetics Models, Genetic Phytophthora/genetics,growth & development,pathogenicity Reproduction/genetics Soybeans/microbiology Virulence/genetics
Authors & Affiliations
3 authors, click to expand affiliations / ORCID
Chamnanpunt J
Department of Plant Pathology, University of California, Davis, CA 95616, USA.
Shan W X
Tyler B M
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Article Info
Journal
Proceedings of the National Academy of Sciences of the United States of America
Abbr.
Proc Natl Acad Sci U S A
ISSN
0027-8424
DOI
10.1073/pnas.251464498
Published
2001-12-04
Epub
2001-00-27
Pages
14530-5
Language
English
Region
United States
NLM ID
7505876
PMCID
PMC64716
Subset
IM
External Links
PubMed source DOI: 10.1073/pnas.251464498 PMC Full Text View journal details
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