To help develop an understanding of the genes that govern the developmental characteristics of the potato (Solanum tuberosum), as well as the genes associated with responses to specified pathogens and storage conditions, The Canadian Potato Genome Project (CPGP) carried out 5' end sequencing of regular, normalized and full-length cDNA libraries of the Shepody potato cultivar, generating over 66,600 expressed sequence tags (ESTs). Libraries sequenced represented tuber developmental stages, pathogen-challenged tubers, as well as leaf, floral developmental stages, suspension cultured cells and roots. All libraries analysed to date have contributed unique sequences, with the normalized libraries high on the list. In addition, a low molecular weight library has enhanced the 3' ends of our sequence assemblies. Using the combined assembly dataset, unique tuber developmental, cold storage and pathogen-challenged sequences have been identified. A comparison of the ESTs specific to the pathogen-challenged tuber and foliar libraries revealed minimal overlap between these libraries. Mixed assemblies using over 189,000 potato EST sequences from CPGP and The Institute for Genomics Research (TIGR) has revealed common sequences, as well as CPGP- and TIGR-unique sequences.

As part of a large-scale genomics project focused on understanding and improving the Shepody potato, we have increased the regeneration and transformation rates for this cultivar. Using combinations of auxins and trans-zeatin, leaf and stem explants were evaluated for callus induction and shoot formation. Several plant growth regulator combinations resulted in higher plant regeneration rates over a previous method. Using the best combination of auxin and cytokinin in combination with Agrobacterium-mediated transformation, we regenerated independent putative transformants from 59.5% of the total explants plated. We ran PCR on a sample of the plants to confirm transformation and 47.1% were nptII positive; giving a confirmed transformation rate of 28.0%.

One of the best known plant disease outbreaks of all time was the Irish potato famine of 1845 to 1847 when the late blight pathogen, Phytophthora infestens, devastated the potato crop and caused more than one million deaths in Ireland. Potatoes are still plagued by disease but luckily most countries do not depend on potato as much as they did in Ireland in the 1800s. Producing disease-free potatoes, however, has come at a huge cost. To combat major diseases, such as late blight and common scab, 64 × 10 6 kg of pesticides are sprayed on potato fields each year. The costs associated with these measures are not only financial; environmental costs, although less easy to quantify, are significant and include negative impacts on natural ecosystems and the contamination of groundwater, lakes, and rivers. Our search for the "perfect" potato, i.e., one that has good processing qualities and disease resistance, has gained new momentum with the emergence of genomic technologies. Through functional genomics we will gain a better understanding of the genes responsible for tuber quality traits and those responsible for disease resistance. With a collection of desirable genes in mind, we can again use genomics as a diagnostic tool to search for these genes in the wide variety of potatoes around the world and to follow their transfer by classical breeding. This paper describes a research program currently underway in Canada that uses functional genomics to improve the potato.

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. 2008. Functional genomic resources for potato. Can. J. Plant Sci. 88: 573Á581. Considerable functional genomic resources have been developed by the potato research community in the past decade, including expressed sequence tag (EST) libraries, SAGE libraries, microarrays, molecular-function maps, and mutant populations. This article reviews the types, characteristics, strengths, limitations, and appropriate applications of these resources for genomic research and discusses perspectives on future directions. This wide selection of resources available to potato researchers complements efforts to sequence the entire genome and advances made in the development of saturated genetic maps.