@article{jin_mccorkle_cornish_carbone_lewis_shew_2022, title={Adaptation of Phytophthora nicotianae to Multiple Sources of Partial Resistance in Tobacco}, volume={106}, ISSN={["1943-7692"]}, DOI={10.1094/PDIS-06-21-1241-RE}, abstractNote={ Host resistance is an important tool in the management of black shank disease of tobacco. Race development leads to rapid loss of single-gene resistance, but the adaptation by Phytophthora nicotianae to sources of partial resistance from Beinhart 1000, Florida 301, and the Wz gene region introgressed from Nicotiana rustica is poorly characterized. In greenhouse environments, host genotypes with quantitative trait loci (QTLs) conferring resistance from multiple sources were initially inoculated with an aggressive isolate of race 0 or race 1 of P. nicotianae. The most aggressive isolate was selected after each of six host generations to inoculate the next generation of plants. The race 0 isolate demonstrated a continuous gradual increase in disease severity and percentage root rot on all sources of resistance except the genotype K 326 Wz/–, where a large increase in both was observed between generations 2 and 3. Adaptation by the race 0 isolate on Beinhart 1000 represents the first report of adaptation to this genotype by P. nicotianae. The race 1 isolate did not exhibit significant increases in aggressiveness over generations but exhibited a large increase in aggressiveness on K 326 Wz/– between generations 3 and 4. Molecular characterization of isolates recovered during selection was completed via double digest restriction-site associated DNA sequencing, but no polymorphisms were associated with the observed changes in aggressiveness. The rapid adaptation to Wz resistance and the gradual adaptation to other QTLs highlights the need to study the nature of Wz resistance and to conduct field studies on the efficacy of resistance gene rotation for disease management. }, number={3}, journal={PLANT DISEASE}, author={Jin, Jing and McCorkle, Kestrel L. and Cornish, Vicki and Carbone, Ignazio and Lewis, Ramsey S. and Shew, H. David}, year={2022}, month={Mar}, pages={906–917} }
 @article{mccorkle_lewis_shew_2013, title={Resistance to Phytophthora nicotianae in Tobacco Breeding Lines Derived from Variety Beinhart 1000}, volume={97}, ISSN={["1943-7692"]}, DOI={10.1094/pdis-05-12-0480-re}, abstractNote={ Black shank, caused by Phytophthora nicotianae, is managed primarily by host resistance. The rapid emergence of race 1 eliminated the usefulness of available complete resistance, leading breeders to search for new sources of resistance. Cigar tobacco ‘Beinhart 1000’ (BH) is highly resistant to all races of P. nicotianae. Doubled-haploid (DH) lines from a cross of BH and the susceptible ‘Hicks’ were evaluated for black shank resistance, and quantitative trait loci (QTL) on linkage groups (LGs) 4 and 8 accounted for >43% of the phenotypic variation in resistance. Forty-three DH lines and parents were evaluated, and genotypes with one or both QTL from BH on LGs 4 and 8 had increased incubation periods and decreased root rot but higher final inoculum levels than genotypes with neither QTL. A low level of stem resistance was observed in BH and DH lines with the QTL from BH on LG 4 but not LG 8. Low levels of leaf resistance were seen for Hicks, BH, and DH lines with both QTL from BH on LG 4 and 8. The partial resistance from BH has not been used commercially and may provide an increase in level of partial resistance in future tobacco varieties. }, number={2}, journal={PLANT DISEASE}, author={McCorkle, Kestrel and Lewis, Ramsey and Shew, David}, year={2013}, month={Feb}, pages={252–258} }