S. V. Zinovieva

The Participation of salicylic and jasmonic acids in genetic and induced resistance of tomato to Meloidogyne incognita (Kofoid and White, 1919)

Salicylic (SA) and jasmonic (JA) acids are the best known mediators of signal systems in plants. In this investigation the participation and character of interactions between SA- and JA-signals under the induced and genetic resistance of plants to nematodes was investigated on the model system tomato (Lycopersicon esculentum) and the root-knot nematode Meloidogyne incognita. This study demonstrates that application of JA and SA to tomato foliage induces systemic effects that suppress root-knot nematode infestation, inhibition of nematode reproduction, and also increased activity of LOX and PAL, the enzymes of biosynthesis of JA and SA. JA treatment did not inhibit Mz-mediated resistance, which suggests a lack of signaling conflicts between these two forms of defense.

Involvement of salicylic acid in induction of nematode resistance in plants

The role of salicylic acid (SA) as a possible signaling component in the case of the infection of plants with nematodes has been studied using a model system consisting of the tomato (Lycopersicon esculentum (Mill.) and race 1 of the gall eelworm Meloidogyne incognita (Kofoid and White, 1919; Chitwood, 1949). The preplanting SA treatment of tomato seeds results in an increased nematode resistance of susceptible tomato cultivars; the protective effect is higher in the case of SA combined with chitosan, a biogenic elicitor of plant resistance. The studied preparations stimulate the growth and development of the plants. The increase in the resistance of tomato plants is related to the increased activity of phenylalanine ammonia-lyase and an increased SA content in plant tissues infected with nematodes; both these factors significantly influence nematode development.

Expression of genes, encoded defense proteins, in potato plants infected with the cyst-forming nematode Globodera rostochiensis (Wollenweber 1923) Behrens, 1975 and modulation of their activity during short-term exposure to low temperatures

The expression of the principal genes providing an immune response in the roots of potato plants resistant and susceptible to the cyst nematode Globodera rostochiensis is investigated under conditions of infestation and with frequent variations in temperature. Differences in the immune status of resistant and susceptible potato cultivars are revealed in the level of expression of R-genes (H1 and Gro1-4), gene PAL, and defense genes of the PR-family (PR1, PR2, PR3, PR6). Varying the temperature changes the activity of transcriptome of susceptible plants towards activation of expression of R-genes, gene PAL, and defense genes; interactions between the plant and parasite are displaced towards induction of host resistance.

Mi-1 gene expression in tomato plants under root-knot nematode invasion and treatment with salicylic acid

The dynamics of expression of two homologous genes Mi-1.1 and Mi-1.2 in the roots of resistant and susceptible tomato plants in non-invasion conditions and during invasion with the root-knot nematode M. incognita was studied. Nematode invasion was accompanied by a significant increase in the expression level of both genes; however, the accumulation of transcripts at the early stages of nematode invasion in the penetration of nematode juveniles to the roots was observed only in plants that contained the Mi-1.2 gene, which explains the resistance of tomatoes to this root-knot nematode, caused by only this gene. We reveal a change in the Mi-1 gene activity under exogenous salicylic acid treatment, which contributed to the formation of induced resistance to root-knot nematode in the susceptible plants.

Expression of PR genes in tomato tissues infected by nematode Meloidogyne incognita (Kofoid et White, 1919) Chitwood, 1949.

The dynamics of expression of PR1 and PR6 genes, which are involved in the defense response of plants infected with the root-knot nematode Meloidogyne incognita, was studied in the “tomato–root-knot nematode” parasitic system. The invasion of the resistant plants was accompanied by an increased accumulation of transcripts of PR genes, which reflects their fast response to the penetration of nematode juveniles with subsequent development of an adequate defense response. In the susceptible plants, changes in the PR1 and PR6 gene activity induced by the nematode invasion were insignificant, which may be one of the causes of the disease. An exogenous salicylic acid treatment of the susceptible plants increased the PR1 and PR6 genes activity and led to the development of resistance of these plants to nematode invasion.

Activity of components of the antioxidant system in the roots of potato plants at short-term temperature drop and invasion with parasitic nematodes

The activity of catalase and superoxide dismutase in the roots of susceptible plants and plants exposed to alternating temperatures, which were infected with the phytoparasitic nematode G. rostochiensis, was studied. It was found that, throughout the invasion period, the plants susceptible to invasion exhibited a high activity of these enzymes, which allowed them to maintain an active defense against the oxidative stress caused by the invasion and subsequent life activity of larvae. For the plants exposed to alternating temperatures, a decrease in the activity of catalase and superoxide dismutase at the early stages of invasion and an increase in the activity of these enzymes at the later stages was detected.

World Collections of Parasitic Worms

This article provides information about the depositories of parasitic worms in the scientific institutes and museums in the United States, Japan, and Europe (the total number of samples and the availability of types of helminths from various classes), as well as information on the availability of electronic catalogues of the collections in the continental, national, and regional centers for collective use. The extent of this material has determined the necessity of creating digital collections and libraries that would represent a new form of storing, displaying, and exchanging information for scientific research. An analysis was performed of the current state of approaches and methods of development of the specialized information retrieval system (IRS) and databases (DBs) on the parasitic worms in Russia on the basis of a common conceptual data model, taking into account their local use (as desktop systems of database management) and access by scientists worldwide via the Internet.