Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC 27695.
Plant Dis. 2022 Feb;106(2):373-381. doi: 10.1094/PDIS-09-20-1972-RE. Epub 2022 Feb 9.
Pathogen adaptation can threaten the durability of partial resistance. Mixed plantings of susceptible and partially resistant varieties may prolong the effectiveness of partial resistance, but little is known about how continued exposure to a susceptible genotype can change the aggressiveness of pathogen isolates adapted to a source of partial resistance. The objective of this study was to examine the effects of continued exposure to a highly susceptible tobacco genotype on isolates of that had been adapted to partial resistance. Isolates of previously adapted to two sources of partial resistance were continually exposed to either the original host of adaptation or a susceptible host. After six generations of host exposure, isolates obtained from the partially resistant and the susceptible hosts were compared for their aggressiveness on the resistant host and for differences in expression of genes associated with pathogenicity and aggressiveness. Results suggested that exposure to the susceptible tobacco genotype reduced aggressiveness of isolates adapted to partial resistance in K 326 but not of isolates adapted to partial resistance in Fla 301. Quantification of pathogenicity-associated gene expression using qRT-PCR suggested the rapid change in aggressiveness of isolates adapted to -sourced partial resistance may have resulted from modification in gene expression in multiple genes.
病原体适应可能会威胁到部分抗性的持久性。感病和部分抗性品种的混合种植可能会延长部分抗性的有效性，但对于病原体分离株在持续接触易感基因型的情况下如何改变适应部分抗性源的分离株的侵袭性，我们知之甚少。本研究的目的是研究继续暴露于高度易感的烟草基因型对先前适应部分抗性的 分离株的影响。先前适应两种部分抗性源的 分离株继续暴露于原始适应宿主或易感宿主。经过六代宿主暴露后，比较从部分抗性宿主和易感宿主获得的分离株在抗性宿主上的侵袭性以及与致病性和侵袭性相关的基因表达差异。结果表明，暴露于易感烟草基因型降低了在 K326 中适应部分抗性的分离株的侵袭性，但在 Fla301 中适应部分抗性的分离株的侵袭性没有降低。使用 qRT-PCR 对与致病性相关的基因表达进行定量，表明适应 - 源部分抗性的分离株侵袭性的快速变化可能是由于多个基因的表达发生了改变。
