Solanum Resistance Gene Cloning Research
Potato is the fourth ranked crop in world food production and late blight of potato caused by Phytophthora infestans is one of its most important diseases. Late blight is mainly controlled by application of enormous amounts of chemicals. However, due to the ability of the pathogen to develop resistance against fungicides and future restrictions on the types of chemicals that can be used by growers, late blight is increasingly difficult to control. There is thus an urgent need for durable resistant potato cultivars. Wild diploid species of potato (Solanum spp.) are potentially a rich source of resistance (R) genes that could be deployed to achieve durable resistance to late blight in modern varieties. We propose that R gene polycultures may provide a means to achieve durable disease resistance by creating transgenic potato varieties that each contain one of a possible say 5 to 10 different R genes in the same elite cultivar (Jones, 2001). Planting these lines as mixtures may increase the durability of the R genes and therefore increase their useful lifespan while maintaining efficient disease control. This theory is currently being modelled through our collaboration with Frank van den Bosch at Rothamsted Research. To achieve durable resistance, we need multiple R genes against late blight. Through intra- and inter-specific crosses, our lab has identified a number of dominant R genes to late blight in various wild diploid potatoes (e.g. Figure 1). Currently our work is focused on the fine mapping and cloning of a number of these genes, as summarised in Table 1. We are coordinating our efforts closely with Dr Edwin van der Vossen’s group in Wageningen.
Solanum R genes currently being mapped and cloned.
Species |
Resistant Accession |
Chromosome |
Gene |
|---|---|---|---|
EBN2 |
|||
| S. okadae |
CGN18108 |
9 |
Rpi-oka1 |
CGN18279 |
9 |
Rpi-oka2 |
|
CGN17998 |
9 |
Rpi-oka3 |
|
S. neorossii |
CGN18000 |
9 |
Rpi-nrs1 |
S. berthaultii |
PI473331 |
10 |
Rpi-ber1 |
PI265858 |
10 |
Rpi-ber2 |
|
EBN1 |
|||
S. mochiquense |
CGN18263 |
9 |
Rpi-mcq1 |
S. brachistotrichum |
CGN17681 |
4 |
Rpi-bst1 |
