Interfacing Classical Breeding and Genomics Towards Diversification of the Genetic Base of Potato Germplasm for Late Blight Resistance
Genetic Improvement of Fruits and Vegetables
2013 Annual Report
1a.Objectives (from AD-416):
To identify and characterize late blight resistance mechanisms from two diverse parents by RNA-Seq technology and combine multiple resistance mechanisms into a single elite donor line. Reduce the impact of late blight through the use of resistant varieties and reduced fungicide programs; Conduct late blight resistance phenotyping of advanced breeding lines and a breeding population for future use in genetic marker development.
1b.Approach (from AD-416):
Intercross late blight resistant clones of Solanum phureja-S. stenotomum with late blight resistance backcross introgression line of S. tuberosum-S. bulbocastanum. Construct RNA-Seq library for resistant and susceptible parents. Sequence transcriptome libraries.
We have developed a functional genomic analysis system to identify novel late blight resistance genes from Solanum bulbocastanum. Sibling backcross lines to S. tuberosum carrying chromosome segment introgressions from S. bulbocastanum were identified and confirmed for broad-spectrum resistance to late blight. Similarities on the type of genes induced by late blight were observed between the sibling introgression lines and their donor S. bulbocastanum parents. Fine scale analysis of the transcriptome data also revealed differences between the two sibling backcross lines. Our preliminary analysis of the data indicates that it is possible to identify the specific R-gene-mediated mechanism responsible for the differential resistance phenotypes of these sibiling lines relative to their donor parents. Upon completion of this study, it is expected that we will be able to identify the broad-spectrum late blight resistance R-genes introgressed from S. bulbocastanum to S. tuberosum. These introgression lines can then be used as donor lines to transfer the late blight resistance gene(s) to other commercial cultivars of potato. The incorporation of these late blight resistance genes into commercial cultivars will benefit growers and the environment by reducing the amount of pesticides applied to commercial fields to control late blight disease.