Mapping genetic factors controlling potato - cyst nematode interactions

The thesis describes strategies for genetic mapping of the genomes of the potato cyst nematode and potato. Mapping in cyst nematodes was achieved by AFLP genotyping of single cysts and subsequent segregation analysis in a family of sibling populations. The genetic map of Globodera rostochiensis comprises nine linkage groups, a number similar to the haploid chromosome number determined. The low kb/cM ratio suggests that map based cloning of (a)virulence genes may be feasible for this organism.For potato, a mapping strategy based on catalogued, chromosome-specific AFLP markers facilitated the mapping of the nematode resistance loci Gpa2 and Grp1 . Gpa2 confers specific resistance to G. pallida and is tightly linked to a virus resistance on potato chromosome 12 . Locus Grp1 is identified by QTL mapping. It confers resistance to G. rostochiensis pathotype Ro 5 , partial resistance to G. pallida and maps on chromosome 5 . The spectra of nematode resistance loci and their positions on the potato genome suggest that these genes are involved in gene-for-gene interactions.</p

Chromosome number of the potato cyst nematode Globodera rostochiensis

Le nombre de chromosome de #Globodera rostochiensis$ a été déterminé par l'analyse de leurs configurations bivalentes au stade métaphase I, de cellules au stade de réduction méiotique pendant l'oogenèse, et de cellules en mitose somatique au cours de divisions embryonnaires prématurées. Le nombre de chromosomes diploïde est 2 n = 18. L'utilisation du fluorochrome Hoechst 33528 a facilité la détermination du nombre de chromosomes dans les globules polaires. Les premières divisions ont été observées en utilisant une méthode d'écrasement améliorée. (Résumé d'auteur

Naturally Induced Secretions of the Potato Cyst Nematode Co-stimulate the Proliferation of Both Tobacco Leaf Protoplasts and Human Peripheral Blood Mononuclear Cells

Naturally induced secretions from infective juveniles of the potato cyst nematode Globodera rostochiensis co-stimulate the proliferation of tobacco leaf protoplasts in the presence of the synthetic phytohormones α-naphthaleneacetic acid (NAA) and 6-benzylaminopurine (BAP). With the use of a protoplast-based bioassay, a low-molecular-weight peptide(s) (<3 kDa) was shown to be responsible for the observed effect. This mitogenic oligopeptide(s) is functionally dissimilar to auxin and cytokinin and, in addition, it does not change the sensitivity of the protoplasts toward these phytohormones. In combination with the mitogen phytohemagglutinin (PHA), cyst nematode secretions also co-stimulated mitogenesis in human peripheral blood mononuclear cells (PBMC). The stimulation of plant cells isolated from nontarget tissue - these nematodes normally invade the roots of potato plants - suggests the activation of a general signal transduction mechanism(s) by an oligopeptide(s) secreted by the nematode. Whether a similar oligopeptide-induced mechanism underlies human PBMC activation remains to be investigated. Reactivation of the cell cycle is a crucial event in feeding cell formation by cyst nematodes. The secretion of a mitogenic low-molecular-weight peptide(s) by infective juveniles of the potato cyst nematode could contribute to the redifferentiation of plant cells into such a feeding cell

Engineering nematode resistance in solanaceae

The present invention relates to the Gpa2 resistance gene from potato conferring resistance to phytopathogenic nematodes of the genus Globodera. It further relates to methods and materials employing the gene and processes for identifying related genes. Finally the invention relates to polypeptides encoded by said resistance genes and the use of said polypeptide

An online catalogue of AFLP markers covering the potato genome

An AFLP marker catalogue is presented for gene mapping within cultivated potato. The catalogue is comprised of AFLP fingerprint images of 733 chromosome-specific AFLP markers which are mapped relative to 220 RFLP loci, isozyme loci, morphological characteristics and disease resistance traits. Use of the catalogue is based on identification of common AFLP markers which are visually recognized on autoradiogram images as co-migrating bands in fingerprints generated from different genotypes. Images of AFLP fingerprints combined with detailed information on the genomic location of all AFLP markers are available at URL: http://www.spg.wau.nl/pv/aflp/catalog.htm. It is demonstrated that the comparison of autoradiogram images and subsequent identification of common AFLP markers solely are efficient means for alignment of linkage groups and mapping target genes