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United States Department of Agriculture

Agricultural Research Service

Research Project: EXOTIC, EMERGING, RE-EMERGING, AND INVASIVE PLANT DISEASES OF HORTICULTURAL CROPS

Location: Horticultural Crops Research

Title: Quantitative resistance to late blight from Solanum berthaultii cosegregates with RPi-ber: insights in stability through isolates and environment

Authors
item Rauscher, G -
item Simko, I -
item Mayton, H -
item Bonierbale, M -
item Smart, C -
item GRUNWALD, NIKLAUS
item Greenland, A -
item Fry, W -

Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 13, 2010
Publication Date: August 6, 2010
Citation: Rauscher, G., Simko, I., Mayton, H., Bonierbale, M., Smart, C.D., Grunwald, N.J., Greenland, A., Fry, W.E. 2010. Quantitative resistance to late blight from Solanum berthaultii cosegregates with RPi-ber: insights in stability through isolates and environment. Theoretical and Applied Genetics. 121:1553-1567.

Interpretive Summary: Genetic resistance is a valuable tool in the fight against late blight of potatoes, but little is known about the stability and specificity of quantitative resistance including the effect of defeated major resistance genes. In the present study, we investigated the effect of different isolates of the potato late blight pathogen, Phytophthora infestans, on the mode of action of two resistance genes derived from the wild relative of potato, Solanum berthaultii. One gene provided complete resistance against a US8 isolate of P. infestans in all trials. A secondary R-gene provided a residual resistance effect. Additional quantitative resistance loci (QRL) were identified in the analyzed progenies. These results will help breeders improve resistance in potato to potato late blight.

Technical Abstract: Genetic resistance is a valuable tool in the fight against late blight of potatoes, but little is known about the stability and specificity of quantitative resistance including the effect of defeated major resistance genes. In the present study, we investigated the effect of different isolates of Phytophthora infestans on the mode of action of RPi-ber, an R-gene originating from Solanum berthaultii. The experiments were conducted on progenies derived from two reciprocal inter-specific backcrosses of Solanum tuberosum and S. berthaultii. The plant–pathogen interaction was tested in diverse environments, including field, greenhouse and growth chamber conditions. The RPi-ber gene provided complete resistance against a US8 isolate of P. infestans in all trials. When isolates compatible with RPi-ber were used for inoculation, a smaller, but significant resistance effect was consistently detected in the same map position as the R-gene. This indicates that this R-gene provides a residual resistance effect, and/or that additional resistance loci are located in this genomic region of chromosome X. Additional quantitative resistance loci (QRL) were identified in the analyzed progenies. While some of the QRL (such as those near TG130 on chromosome III) were effective against several isolates of the pathogen, others were isolate specific. With a single exception, the S. berthaultii alleles were associated with a decrease in disease severity. Resistance loci reported in the present study co-locate with previously reported R-genes and QRL to P. infestans and other pathogens.

Last Modified: 9/10/2014
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