Different Reactions of Potato Varieties to Infection by Potato Leafroll Virus , and Associated Responses by its Vector, Myzus persicae (Sulzer)

Vector-dependent plant pathogens can alter their hosts such that vector behavior and pathogen spread are affect- ed. For example, Potato leafroll virus (PLRV)-induces changes in volatiles emitted by potato plants (Solanum tuberosum L.) that influence settling behavior by Myzus persicae ,ap rincipal vector of the virus. Prior work in this pathosystem has utilized a single potato variety, Russet Burbank, but as is true for other plant responses to biotic stresses, responses may differ among plant genotypes. To examine this, PLRV-induced changes in headspace volatile organic compounds (VOCs) and associatedaphid responses to these VOCswere compared among four potato varieties (Chipeta, Desiree, IdaRose, and Russet Burbank). Total headspace VOCs differed among the varieties and were differentially induced by PLRV infection such that the effect of variety, infection, and their interaction was significant; two of the varieties had increased concentra- tions of headspace VOCs, and two did not. MANOVA for the effect of infection and variety on total VOCs and major VOC classes also was significant. A principal component analysis (PCA) partially separated the VOC profiles from the four varieties. Aphid arrestment differed in response to the VOCs of the four varieties, and was greater on those that were more readily infected by PLRV (Desiree and Russet Burbank) as compared with those that were less readily infected (Chipeta and IdaRose). Aphid responses were not clearly related to specific characteristics of blends, such that total VOCs and composition appear to contribute. The four varieties used in this study have distinct pedigrees representative of different cultivated forms of S. tuberosum. Although cultivated potato varieties have been subjected to genetic manipulation by humans, the differences in PLRV induced changes in VOCs nonetheless indicate the potential for complex effects of PLRV infection on host plant VOC emissions, and vector responses in managed, and natural systems.