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ARS Home » Midwest Area » Madison, Wisconsin » Vegetable Crops Research » Research » Publications at this Location » Publication #330147

Research Project: Resources for the Genetic Improvement of Potato

Location: Vegetable Crops Research

Title: Determination of virulence contribution from Phytophthora infestans effector IPI-O4 in a resistant potato host contaning the RB gene

Author
item Chen, Yu - University Of Wisconsin
item Halterman, Dennis

Submitted to: Physiological and Molecular Plant Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/24/2017
Publication Date: 5/29/2017
Citation: Chen, Y., Halterman, D.A. 2017. Determination of virulence contribution from Phytophthora infestans effector IPI-O4 in a resistant potato host containing the RB gene. Physiological and Molecular Plant Pathology. 100:30-34. doi: 10.1016/j.pmpp.2017.05.006.

Interpretive Summary: The potato late blight resistance (R) gene RB is distinct from most plant R genes in that it confers resistance to a broad spectrum of pathogen isolates. RB recognizes the presence of members of the Phytophthora infestans effector family IPI-O to elicit resistance. One member within the IPI-O family acts to suppress resistance mediated by RB. In this manuscript, we investigate the contribution that IPI-O effectors make to pathogen growth in potato hosts that contain the RB gene. We found that both IPI-O1 and IPI-O4 effectors contribute to increased disease symptoms in the presence of the RB gene.

Technical Abstract: Potato late blight, caused by the oomycete pathogen Phytophthora infestans, is one of the most destructive plant diseases. Despite decades of intensive breeding efforts, it remains a threat to potato production worldwide, because newly evolved pathogen strains have overcome major resistance genes quickly. The RB protein, from the diploid wild potato species Solanum bulbocastanum, confers partial resistance to most P. infestans strains through its recognition of members of the corresponding pathogen effector protein family IPI-O. IPI-O comprises a multigene family and while some alleles are recognized by RB to elicit host resistance (e.g. IPI-O1, IPI-O2), others are able to elude detection (e.g. IPI-O4). In our previous research, we found that in planta expression of P. infestans effector IPI-O4 is able to suppress the HR elicited by IPI-O1 in the presence of RB in N. benthamiana leaf via agro-infiltration. Additionally, we have observed that strains of P. infestans containing IPI-O4 are able to cause more disease on RB plants compared to strains without IPI-O4. This has led to a hypothesis that the presence of IPI-O4 results in suppression of RB. In this study, we provided evidence that in planta over-expression of IPI-O4 was able to suppress RB-mediated resistance and assist P. infestans strain US24 to cause an enlarged lesion in RB containing K41 potato lines compared to the wild type K41 plants. The results of this study will further our understanding on the outcome of interaction between RB containing hosts and IPI-O4 containing P. infestans strains.