Induction of Resistance to Phytophthora in Tubers of Transgenic Potato

Resistance of transgenic cultivars based on the expression of one or more resistance genes is sooner or later broken by pathogens whose race-producing rates are high. Thus, combining transgenesis with elicitor-induced resistance is a promising approach. The elicitor-induced resistance is based on the expression of multiple resistance genes, which can prevent the adaptation of pathogens to transgenic cultivars, maintain the stability of cultivars, and increase their lifespan. In this work, we used transgenic potato cultivars Temp and Superior transformed with Bacillus thuringiensis -endotoxin gene and Luk'yanovskii transformed with leukocyte interferon gene. Arachidonic acid (10^–8 M) and soluble chitosan (5 kDa, 100 g/ml) were used as elicitors for tuber treatment. Our data showed that pretreatment with elicitors causes a 15–25% increase in both the systemic prolonged resistance of potato tubers to Phytophthora infestansand their ability to repair mechanical damage.     

Plant Resistance Suppressors in the Pathosystem Formed by Potato and the Causal Agent of Late Blight

The properties and effects of two plant resistance suppressors (1,3--1,6--glucan and a pentasaccharide of xyloglucan origin) involved in the pathosystem of potato (Solanum tuberosum) and the causal agent of blight (Phytophthora infestans(Mont) de Bary) were compared. The microbial 1,3--1,6--glucan suppressed the defense response over a narrow concentration range (10^–2M), whereas the plant pentasaccharide had a broad range of effective concentrations (10^–12to 10^–6M). In the pathosystem of potato and the causal agent of late blight, the -glucan caused a local and race-specific suppressor effect on the plant host defense response. In contrast, the pentasaccharide caused both local and systemic suppression of potato resistance and the presence of terminal fucosyl residue in the xyloglucan oligosaccharine played a decisive role in its effect. The recognition of both suppressors by potato cell membrane sites is discussed.     

Biochemical Aspects of Plant Interactions with Phytoparasitic Nematodes: A Review

The review summarizes reports on molecular aspects of interactions of phytoparasitic nematodes with plant hosts. Data on nematode secretions affecting plants (elicitors, toxins, products of parasitism genes, etc.) are analyzed and information flow pathways comprising all elements of the plant–parasite interaction (from elicitors to defense responses of plant cells) are described. Emphasis is placed on the mechanisms whereby plants are protected from nematode invasion (hypersensitivity reactions, apoptosis, phytoalexins, proteinase inhibitors, PR proteins, etc.). Consideration is given to genetic aspects of plant–parasite relationships. Promising practical approaches to defending plants from phytoparasitic nematodes developed based on the results of studies of molecular mechanisms of plant–parasite interactions are presented in the conclusion.     

Influence of Systemic Signal Molecules on the Rate of Spread of the Immunizing Effect of Elicitors over Potato Tissues

Mobile systemic signal molecules (salicylic and jasmonic acids) enhance and accelerate the spread of the systemic immunizing effect of elicitors (arachidonic acid and chitosan) over potato tuber tissues (Solanum tuberosum L.).