Testing taxonomic predictivity of foliar and tuber resistance to Phytophthora infestans in wild relatives of potato

Authors: KHIUTTI, ALEX - All-Russian Institute For Plant Protection; Jansky, Shelley; Spooner, David; Halterman, Dennis

Submitted to: Phytopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/8/2015
Publication Date: 4/14/2015
Publication URL: http://handle.nal.usda.gov/10113/61538
Citation: Khiutti, A., Spooner, D.M., Jansky, S.H., Halterman, D.A. 2015. Testing taxonomic predictivity of foliar and tuber resistance to Phytophthora infestans in wild relatives of potato. Phytopathology. 105(9):1198-1205.

Interpretive Summary: This publication presents data on the screening on wild potato germplasm for resistance to the late blight pathogen, Phytophthora infestans. Screening germplasm for disease resistance is a time consuming process and being able to predict whether a certain species is resistant based on its relationship with other species would be beneficial. In this study we screened a large number of wild potato species in order to test whether species with resistance were closely related to other species with resistance. We also tested whether there was a relationship between resistance and the location of where the species was collected. Overall, we found no relationship between species that contained disease resistance and could not predict whether a species was resistant based on its location. This suggests that in order to identify late blight resistance in wild potato germplasm, a thorough screen of all available species is necessary. The results are important because it contradicts the assumption that a relationship between species could be used to predict disease resistance. Our findings will benefit plant pathologists and potato breeders interested in identifying new sources of late blight resistance. The results will impact these scientists through the identification of previously unknown sources of late blight resistance and also by reporting new methodologies that could be used for large scale screening for disease resistance in potato.

Technical Abstract: Potato late blight, caused by the oomycete phytopathogen Phytophthora infestans, is a devastating disease found in potato growing regions worldwide. Long-term management strategies to control late blight include the incorporation of host resistance to predominant strains. However, due to rapid genetic changes within pathogen populations, rapid and recurring identification and integration of novel host resistance traits is necessary. Wild relatives of potato offer a rich source of desirable traits, including late blight resistance, but screening methods can be time intensive. We tested the ability of taxonomy, ploidy, crossing group, breeding system, and geography to predict the presence of foliar and tuber late blight resistance in wild Solanum species. Significant variation for resistance to both tuber and foliar late blight was found within and among species but there was no discernable predictive power based on taxonomic series, clade, ploidy, breeding system, elevation, or geographic location. We observed a moderate but significant correlation between tuber and foliar resistance within species. Although previously uncharacterized sources of both foliar and tuber resistance were identified, our study does not support an assumption that taxonomic or geographic data can be used to predict sources of late blight resistance in wild Solanum species.