Cloning and utilization of new naturally occurring Late Blight and Colorado potato resistance genes to reduce the use of pesticides in potatoes

Project code: PRR03-140

Project Lead

Qin Chen - Agriculture and Agri-Food Canada

Objective

To develop potato varieties with improved resistance to late blight and Colorado Potato Beetle

Summary of Results

Worldwide potato late blight and the Colorado potato beetle (CPB) are the most devastating disease and insect pests of potatoes. About 20 million kilograms of pesticide is used annually for controlling these pests in Canada.

Host plant resistance offers long-term, sustainable and cost-efficient pest control, which is an important part of an integrated pest management (IPM) system. The four year research was undertaken to improve resistance to late blight and CPB in potatoes and to address increasing restrictions on the use of chemical pesticides by providing new disease and insect resistance genes and high quality, resistant potato germplasm/cultivars to meet a growing market demand for french fries and chips.

In the course of the project, we successfully explored and used new disease and insect resistance genes present in Mexican wild species (Solanum pinnatisectum) to produce resistant potatoes and used them as environmentally-friendly alternatives to pesticides for reducing the use and risks associated with pesticides.

Different transfer strategies and techniques were tested and compared. Techniques of somatic hybridization through protoplast fusion were selected and established as a gene transfer system for the efficient incorporation of genes from wild Mexican species into cultivated potato. Potato clones with resistance to late blight and CPB for integration into elite germplasm were produced. This is the first time that late blight and CPB resistant potato somatic clones have been produced from Mexican wild species S. pinnatisectum. Two BAC (Bacterial Artificial Chromosome) libraries constructed from DNA of S. pinnatisectum and carrying late blight and CPB resistance genes were characterized and analyzed using different RFLP (restriction fragment length polymorphism) markers, which were linked to the resistance genes for late blight, CPB, Verticillium wilt and potato cyst nematodes.

Studies conducted during the past four years have generated much more information than initially anticipated and have provided new knowledge and new techniques for characterization, evaluation and production of new resistant potatoes.

Further funding has been provided to the researcher to backcross the new resistant somatic hybrids to elite commercial potato lines (project PRR08-010). Afterwards, the super improved potato lines will be selected for resistance to late blight and CPB and agronomically significant traits.

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