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The cultivated potato is sensitive to a wide range of biotic (e.g. pathogens and pests) and abiotic stresses (e.g.drought, low and high temperatures), leading to losses in production almost every year. At the same time, a number of wild tuberbearing Solanumspecies represent valuable genetic resources where breeders can recover private genes and alleles to improve resistance traits. With these in mind, our laboratory aimed different research projects to improve the cultivated potato for environmental stress resistance and quality traits through integrated conventional and genomic approaches. Main sources of resistance are species such as S. commersoniiS. bulbocastanumS. multidissectumS. phurejaas well as genotypes of cultivated S. tuberosum. We are currently using in vitro approaches to ascertain the level of resistance of a number of clones from these species. We are also exploiting an important genomic resource we recently provided. Indeed, we sequenced the genome of the most interesting cold tolerant wild potato, S. commersonii, making ita model species for studying plant tolerance to cold as well as other stresses. The new genomic resource allowed us to disclose and characterize two gene families directly involved in small non-coding RNA (ncRNA) production: DICER(DCL) and RNA-dependent RNA polymerase(RDR). The analysis of evolutionary features of these genes revealed that tandem duplication events are the main evolutionary forces underlying the expansion of both gene families in potato, whereas expressional profiles provided evidence for their differential role under non-acclimated (NACC) and acclimated (ACC) conditions. We also analyzed and determined the sncRNAome (the main products of DCLand RDR activity) of two clones of S. commersonii contrasting in their cold response phenotypes using next generation sequencing (NGS) approach, revealing a prevalence of 21- and 24-nt sncRNAs. Our results reveal possible roles of sncRNA in the regulatory networks associated with tolerance to low temperatures and provide useful information for a more strategic use of genomic resources in potato breeding.

Cultivated and wild potatoes are rich sources of several metabolites. These metabolites have wide uses in agronomic (natural anti-fungi compounds) and industrial (food-technological processes and pharmaceutical preparation) fields. Most of these compounds enhance the nutritional value of tubers and tuber biofortification has recently became an interesting target for ourlaboratory. We are involved in unlocking the genetic basis underlining the natural potato diversity in metabolites produced and also into identification of genes regulating the biosynthesis of such compounds. We are focused on the molecular regulation of phenolic (anthocyanins, flavonoid and hydroxycinnamic acids) and starch. The former compounds are of great interest for their beneficial effects on plant physiological processes and human health and are also involved in the crop defense mechanisms. In our studies, we identified regulatory complexes basing the anthocyanin biosynthesis in potato and genes that could affect the activation of phenylpropanoid pathway under cold stress. Currently, we are producing anthocyanins in potato cell cultures through the use of genome editing approaches (i.e CRISPR/Cas9 method) and the identification (-omics method) and functional characterization of decorative encoding genes that make anthocyanin molecules more stable for several industrial processes. In collaboration with other research groups, we are also testing the antiproliferative effects of potato anthocyanins and other phenolic metabolites on both human tumors and plant pest and pathogens. 

Another important field of studies is related to potato starch. It represents an important source of energy and, especially in potato, starch can also form different microstructures that influence the nutritional value and the kind of exploitation in industrial processes. We are performing association studies to identify genetic variants underlining several potato tuber starch traits: e.g. amylose, amylopectin and granule starch composition. Scanning electron microscopy (SEM) analyses and biochemical studies on starch are conducting in collaboration with colleagues of food science and technology for phenotyping studies. The final goal is to make the potato starch composition more suitable for different industrial applications.

1 Structural genomics of wild potato species based on DArT alignments (abstract & poster) web manager