Goal: Sustain Our Nation’s Forests and Grasslands Mapping Phytophthora root rot resistance genes in American chestnut
Phytophthora root rot is a serious disease of American chestnut that jeopardizes the success of chestnut restoration in the South. Using hybrid crosses and genomic techniques, SRS scientists mapped the major genes for resistance to Phytophthora cinnamomi, the microbe that causes this disease. The gene map is helping chestnut breeders and genetic engineers improve chestnut for planting on impacted sites.
Phytophthora cinnamomi, a soilborne oomycete, is a lethal pathogen of American chestnut (Castanea dentata). The microbe causes Phytophthora root rot (PRR) and is particularly damaging to chestnut and chinquapin in the southern U.S. Developing resistant genotypes is the most practical solution for disease management in forest trees such as Castanea.
Using backcross families derived from crosses of American chestnuts with two resistant Chinese chestnut genotypes (‘Mahogany’ and ‘Nanking’), the researchers genetically mapped quantitative trait loci for resistance to P. cinnamomi. In total, 957 plants representing five cohorts of three hybrid backcrosses were genotyped by sequencing and phenotyped using artificial inoculations.
The results imply that the genetic architecture of resistance to P. cinnamomi in Chinese × American chestnut hybrids resemble the P. sojae–soybean pathosystem and should allow chestnut breeders to efficiently produce resistant American chestnuts for restoration.
- Principal Investigator
- C. Dana Nelson, Project Leader
- 4160 - Forest Genetics and Ecosystems Biology
- Strategic Program Area
- Resource Management and Use
- Dissecting resistance to Phytophthora cinnamomi in interspecific hybrid chestnut crosses using sequence-based genotyping and QTL mapping
- Research Partners
- Tatyana Zhebentyayeva, Penn State University
- Steven N Jeffers, Clemson University
- Margaret Staton, University of Tennessee
- Albert Abbott, University of Kentucky
- Barbara Crane, Regional Geneticist, Southern Region
- External Partner
- Jared Westbrook, The American Chestnut Foundation