Location: Vegetable Crops Research
Project Number: 5090-21220-002-18-S
Project Type: Specific Cooperative Agreement
Start Date: Aug 1, 2014
End Date: Jul 31, 2017
Our specific objectives are to: 1. Generate tetraploid populations from crosses between Ve homozygotes and susceptible cultivars and evaluate the resistance phenotype in these populations. 2. Measure Ve, SERK1, and SERK3/BAK1 gene expression in the populations generated in Objective 1 and relate this to the resistance phenotype.
A study of Verticillium Wilt (VW) resistance in potato identified a single dominant gene that confers VW resistance in the wild diploid Solanum species S. chacoense. In our ARS lab, we described a similar genetic mechanism in diploid interspecific hybrids, with two major genes required for resistance. One likely candidate for a potato VW resistance (R) gene is a relative of the tomato Ve gene, which has been successfully used in tomato breeding for several decades. Although resistance conferred by Ve is a dominant trait, the gene does not appear to act alone. In our program, we have identified a diploid clone (C287) that is homozygous for Ve. We have somatically doubled this clone to create a series of tetraploids (JP clones) that carry the resistance allele on each of the four chromosomes. The JP clones are consistently resistant to Verticllium wilt in field trials. Three JP clones have been crossed as males to the susceptible cultivar White Pearl. All progeny presumably carry Ve, so they were expected to be resistant to Verticillium wilt. However, some are susceptible. Germplasm carrying Ve will be valuable for breeders seeking to develop resistant cultivars. However, before we release Ve-carrying clones as parental lines, it is important to identify the variables that influence the resistance phenotype in clones carrying Ve, especially if those clones are derived from popular potato cultivars. The cooperator will assist in developing tetraploid populations that are segregating for resistance. These populations will be evaluated for resistance using greenhouse inoculation assays. The cooperator will be responsible for developing protocols for quantification of gene expression and assaying expression in the populations developed in objective 1.