Genetische Diversität für die Widerstandsfähigkeit gegen Schaderreger bei Kartoffel

Zur Erweiterung der genetischen Diversität der Kulturkartoffel wurde ein umfangreicher Wildkartoffel-Genpool auf bislang züchterisch noch ungenutzte wertvolle Genvarianten für Krankheitsresistenz evaluiert. Verschiedene mögliche Resistenzdonoren wurden hinsichtlich ihrer züchterischen Nutzung analysiert. Durch den Einsatz der somatischen Hybridisierung können auch Wildkartoffelarten, die bisher aufgrund ihrer Kreuzungsbarrieren nur schwer für die Züchtung zugänglich waren, in Züchtungsprogramme integriert werden. Somit kann der Genpool der Kulturkartoffel stetig erweitert und die genetische Diversität für Widerstandsfähigkeit gegen Krankheiten (Virosen, Bakterien) und Schädlinge (Blattläuse, Kartoffelkäfer) nachhaltig verbessert werden. Gegenwärtig sind Zuchtstämme mit geringerer Anfälligkeit für die Kraut- und Braunfäule verfügbar. Stichwörter: Pflanzengenetische Ressourcen, Wildkartoffelarten, Protoplastenfusion, Kartoffelvirus Y, Kraut- und Braunfäule, KartoffelzuchtprogrammImprovements in the genetic diversity of potato associated with resistance to diseases and pestsAbstractIn order to increase the genetic diversity of common potato, Solanum tuberosum, wild diploid tuber-bearing Mexican potato species were screened for genetic variants that could be used in breeding programmes to improve the resistance of potato to diseases and pests. Genebank accessions of Solanum cardiophyllum, S. pinnatisectum and S. tarnii are extremely resistant to potato virus Y, late blight and Colorado potato beetle, and those of S. bulbocastanum and S. demissum to late blight and nematodes. Somatic hybridization by protoplast fusion or inter-specific crosses can be used to combine the genomes of these wild species with that of cultivated potato. Methods, like in situ hybridization techniques (GISH), flow cytometry, molecular markers and phytopathological analysis are used to select plant material with these important characters.Recently, breeding lines with improved resistance to pathogens and pests and acceptable agronomic traits have been developed and are being integrated into pre-breeding material in potato breeding programmes. This plant material is also of interest for fundamental research on the genetics of resistance in plants to pests and diseases.Keywords: Plant genetic resources, wild potato species, protoplast fusion, Potato virus Y, late blight, potato breeding programm

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

Transfer of diseases resistance from wild species of the genus Solanum to potato through somatic hybridization

vokKJB. Yksikön huom.: KJ

Intergenomic chromosome pairing in the allodiploid Solanum etuberosum - tomato hybrids: an assessment through GISH

vokKJB. Yksikön huom.: KJ

Cytogenetic analysis of Lycopersicon esculentum (+) Solanum etuberosum somatic hybrids and their androgenetic regenerants

vokKJ

Cytological investigation of somatic hybrids Lycopersicon esculentum (+) Solanum etuberosum and their anther-derived regenerants produced by direct embryogenesis

vokKJ

Identification of the E- and A- parental genomes in interspecific somatic hybrids of potato and their progenies by genomic in situ hybridization

vokKJ

Chromosome pairing relationships among the genomes A, E and L of Solanum species

vokKJB. Yksikön huom.: KJ

Performance and feeding behaviour of potato colonising aphids on S. etuberosum (+) S. tuberosum somatic hybrids and progenies with different glycoalkaloid compositions

Abstrakti nro 50vokKJB. Yksikön huom.: KJ

Use of somatic hybridisation to transfer resistance to late blight and Potato Virus Y (PVY) into cultivated potato

Protoplast fusion was used to produce more than 500 symmetric interspecific somatic hybrids between wild Solanum species, which belong to the series Pinnatisecta, Etuberosa and S. tuberosum L. cultivars or potato breeding clones. The used genebank accessions of S. cardiophyllum and S. tarnii were resistant to Phytophthora infestans, while the accessions of S. cardiophyllum, S. tarnii, as well as of S. etuberosum, were also highly resistant to PVY (strains: PVYO, PVYN, PVYNTN, PVYC, PVYN Wilga). In most fusion combinations vigorous and genetically stable hybrid material has been selected. A number of interspecific somatic hybrids were fertile and could be backcrossed with cultivated potato. The use of detached leaf and tuber tests and mechanical inoculation, grafting and virus transmission by vectors, revealed that several somatic hybrids and backcross (BC) clones were resistant to foliage and tuber blight, as well as to PVY