Biotechnological Strategies for a Resilient Potato Crop

The aim of this chapter is to describe in a synthetic manner the most efficient biotechnological techniques which can be applied in potato breeding with emphasis on multiple resistance traits. To this end, most important results of all biotechnological techniques will be pointed out including new biotechnological tools of genome editing. The somatic hybridization will be the core of the presentation as the only non-GMO strategy with good results in transferring multiple resistances into potato gene pool. The chapter is presenting all data in a synthesized form and made comparisons between the existing techniques and their possible adoption in breeding in different parts of the world, depending on regulations and consumer choice. Moreover, the recently discovered value of potato as a healthy food and its possible applications in cancer treatment will be also discussed with new data on both potato and some of its wild relatives

In vitro culture and medium-term conservation of the rare wild species Gladiolus imbricatus

Gladiolus imbricatus, a rare species spread in the hill region of Europe, is resistant to abiotic and biotic stress being one of the most cold-tolerant in the genus. Moreover it contains high vitamin C and minerals in the leaves and the flowers are considered as edible. The aim of our study was to develop in vitro technologies for micropropagation, multiplication, corm development, somatic embryogenesis and medium-term storage of this endangered species, Red listed in South-Eastern and Central European countries. Initiation of in vitro cultures was started from wounded seeds or excised mature embryos. Micropropagation and multiplication was achieved on Murashige Skoog (MS) solid medium with 30 g L-1 sucrose and 1 mg L-1 N-6-benzyl adenine (BA). The callus developed from wounded seeds on a richer MS medium proved to be embryogenic. Increased concentrations of sucrose promote corm development as also shown for other genotypes of cultivated gladioli. Further on a two-step culture protocol, on solid and liquid shaken MS based media, each for 6 months was done to evaluate the effects of acetic acid and ancymidol on corm development. Acetic acid + sucrose 9%, alone or in combination with ancymidol stimulated corm formation and yield. For medium term conservation maintenance of the in vitro cultures in low temperature in the dark proved to be the best in reducing the growth rate of the shoots after 3, 6 and 12 months. The recovery of plant growth was evaluated after 12 months, by the transfer to normal growth conditions. 25% of the plants were recovered after one year storage. Besides the importance for biotechnology, the in vitro techniques described here might be used, after molecular analysis of genetic stability, for the restoration of natural populations into the habitats where this species became extinct.Keywords: Acetic acid, ancymidol, corm development, somatic embryogenesi

Drought and saline stress tolerance induced in somatic hybrids of solanum chacoense and potato cultivars by using mismatch repair deficiency

Global climate change, especially when involving drought and salinity, poses a major challenge to sustainable crop production, causing severe yield losses. The environmental conditions are expected to further aggravate crop production in the future as a result of continuous greenhouse gas emissions, causing further temperature rise and leading to increased evapotranspiration, severe drought, soil salinity, as well as insect and disease threats. These suboptimal growth conditions have negative impact on plant growth, survival, and crop yield. Potato is well known as a crop extremely susceptible to drought, which is primarily attributed to its shallow root system. With potato being the fourth major food crop, increasing potato productivity is thus important for food security and for feeding global population. To maintain a sustainable potato production, it is necessary to develop stress tolerant potato cultivars that cope with the already ongoing climate change. The aim of our study is to analyze the response of potato somatic hybrids to drought and salt stress under in vitro conditions; the somatic hybrids studied are the wild relative Solanum chacoense (+) Solanum tuberosum, with or without mismatch repair deficiency (MMR). Upon this selection of drought and salt tolerant genotypes, somatic hybrids and their parents were phenotyped on a semi-automated platform, and lines tolerant to medium water scarcity (20% compared to 60% soil water capacity) were identified. Although none of the parental species were tolerant to drought, some of the MMR-deficient somatic hybrids showed tolerance to drought and salt as a new trait. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

New Phenotypes of Potato Co-induced by Mismatch Repair Deficiency and Somatic Hybridization

As plants are sessile they need a very efficient system for repairing damage done by external or internal mutagens to their DNA. Mismatch repair (MMR) is one of the systems that maintain genome integrity and prevent homeologous recombination. In all eukaryotes mismatches are recognized by evolutionary conserved MSH proteins often acting as heterodimers, the constant component of which is MSH2. Changes affecting the function of MSH2 gene may induce a ‘mutator’ phenotype and microsatellite instability (MSI), as is demonstrated in MSH2 knock-out and silenced lines of Arabidopsis thaliana. The goal of this study was to screen for ‘mutator’ phenotypes in somatic hybrids between potato cvs. ‘Delikat’ and ‘Désirée’ and MMR deficient Solanum chacoense transformed using antisense (AS) or dominant negative mutant (DN) AtMSH2 genes. The results demonstrate that first generation fusion hybrids have a range of morphological abnormalities caused by uniparental MMR deficiency; these mutant phenotypes include: dwarf or gigantic plants; bushiness; curled, small, large or abnormal leaves; a deterioration in chloroplast structure; small deep-purple tubers and early dehiscent flowers. Forty percent of the viable somatic hybrids planted in a greenhouse, (10 out of 25 genotypes) had mutant phenotypes accompanied by MSI. The majority of the hybrids with ‘mutator’ phenotypes cultured on media containing kanamycin developed roots so sustaining the presence of selectable marker gene nptII, from the initial constructs. Here for the first time, MMR deficiency combined with somatic hybridization, are used to induce new phenotypes in plants, which supports the role of MMR deficiency in increasing introgressions between two related species

Combining marker assisted selection (MAS) and somatic hybridization for better introgression of resistance genes into cultivated potato

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The genotype of potato variety plays an important role for the genetic constitution of somatic hybrids: Solanum tuberosum + late blight resistant S. bulbocastanum

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