Location: Vegetable Crops Research Unit
2013 Annual Report
1. Conduct transformations with candidate sequences of a putative S. microdontum R-gene.
2. Identify functional orthologs of the late blight R-gene RB from disease resistant wild germplasm and test the functionality of these genes using a transient expression assay.
3. Evaluate the late blight resistant potato advanced breeding lines including the varieties 'Defender' and 'Jacqueline Lee' for resistance to Blue 13 and identify the presence of genes that recognize P. infestans effectors.
4. Evaluate the effect of pyramiding the RB with conventionally bred late blight resistant lines.
For the evaluation of oospores survivability, three different concentrations of oospores from each combination of mating types were used. The oospore concentrations were 100, 1,000, and 10,000 in 100 g of soil. Incubation under 5 different temperatures: 22, (room temperature), 0, -10, -20, and -80°C, for periods of time ranging from 1 to 4 months. Infested soils were sampled at each temperature and time period to assess infectivity of oospores. Minitubers were planted into infected soils to assess infectivity of the oospores. This experiment was performed in winter-spring 2011-2012 and infectivity was evaluated. A second experiment is underway in winter-spring 2012-2013. Our results showed that potato plants from minitubers planted in infested soil with oospores from the winter 2011-2012 did not show any symptoms of late blight after 60 days of planting. This research relates to objective 4 of the project through the determination of the overwintering capabilities of P. infestans strains and objective 5 through the determination of P. infestan's ability to form oospore progeny through sexual recombination.