Molecular characterization and functional importance of pectate lyase secreted by the cyst nematode Heterodera schachtii.

SUMMARY To analyse the parasitic behaviour of the plant-parasitic nematode Heterodera schachtii, proteins secreted by this nematode were purified and separated by two-dimensional gel electrophoresis. Mass spectrometric analysis identified one of the spots as a pectate lyase (EC 4.2.

Differential activation of ABI3 and LEA genes upon plant parasitic nematode infection.

SUMMARY Promoter activity of ABI3 and of three LEA genes was monitored in Arabidopsis transgenics infected with Heterodera schachtii and Meloidogyne incognita. ABI3::GUS expression was induced (in four different promoter deletion constructs) during early infection stages with H. schachtii.

An SXP/RAL-2 protein produced by the subventral pharyngeal glands in the plant parasitic root-knot nematode Meloidogyne incognita.

Meloidogyne incognita is a major parasite of numerous plant families, including many crop species. Upon infection of the plant root, it induces several multinucleate giant cells by the injection of pharyngeal gland secretions into the root cells. In order to obtain a better understanding of the nematode-plant interaction, characterization of the pharyngeal gland secretions is a necessity.

A new class of ubiquitin extension proteins secreted by the dorsal pharyngeal gland in plant parasitic cyst nematodes.

By performing cDNA AFLP on pre- and early parasitic juveniles, we identified genes encoding a novel type of ubiquitin extension proteins secreted by the dorsal pharyngeal gland in the cyst nematode Heterodera schachtii. The proteins consist of three domains, a signal peptide for secretion, a mono-ubiquitin domain, and a short C-terminal positively charged domain. A gfp-fusion of this protein is targeted to the nucleolus in tobacco BY-2 cells.

Secretions of plant-parasitic nematodes: a molecular update.

The interaction between sedentary endoparasitic nematodes and plants is fascinating, because these animals have developed an ingenious way to manipulate the plant's gene regulation and metabolism to their own advantage. They are able to form highly specialized feeding structures in the plant root to satisfy their nutritional demands for development and reproduction. This ability makes them extremely successful parasites with severe consequences for agriculture.

Identification of cytokinins produced by the plant parasitic nematodes Heterodera schachtii and Meloidogyne incognita.

SUMMARY The presence of different types of cytokinins was analysed in exudates and lysates of stage-2 juveniles of Heterodera schachtii and Meloidogyne incognita and in mixed stages of Caenorhabditis elegans. For all species, cytokinins were detected in lysates and exudates in which benzyladenine and zeatin-type cytokinins were the most prominent forms. The production of cytokinins by Meloidogyne was much higher than by Heterodera, and the detected levels were in a range which interfered with the physiological activities of the host plant.

A simplified whole mount in situ hybridization protocol using DIG-labelled DNA probes to visualize gene activity in Heterodera schachtii.

Information concerning gene expression during the nematode's life cycle is rapidly accumulating as a result of different screening approaches. In the majority of the cases, the initial characterization of these genes involves determination of their temporal and tissue-specific expression patterns. This preliminary insight into the characteristics of newly isolated genes allows the formulation of a hypothesis and sets the course for further research.

An improved method for whole-mount in situ hybridization of Heterodera schachtii juveniles.

An optimized protocol is presented to visualize gene expression in the sedentary beet cyst nematode, Heterodera schachtii, by whole-mount in situ hybridization. Two different probes were used for genes with known expression pattern in other nematodes. Vacuum infiltration of the fixative significantly increased its efficiency and resulted in a nicely preserved morphology.