Cross adaptation of potato plants to low temperatures and potato cyst nematode infestation

Effect of short-term (2 h a day) and long-term (6 days) exposure to low temperature (5°C) on cold tolerance was investigated in two cultivars of potato (Solanum tuberosum L.): resistant (Sudarynya) and susceptible (Nevskii) to potato cyst nematode (Globodera rostochiensis Woll.). The extent of their infestation and changes in the expression of the genes of resistance to nematode (H1 and Gro1-4) were also analyzed. In both cultivars, exposure to low temperature enhanced cold resistance of potato plants. Enhancing cold resistance of cv. Sudarynya induced by a short-term exposure to chilling did not affect the extent of nematode infestation, whereas in susceptible cv. Nevskii, the extent of infestation decreased by almost three times. The level of expression of H1 gene in the leaves of the susceptible cultivar rose almost twofold both after short-term and long exposure to chilling, while in the resistant cultivar, gene expression increased only after a short-term effect of cold. The level of Gro1-4 gene expression increased after both temperature treatments only in the resistant cv. Sudarynya. Thus, the expression of genes for potato resistance to nematode infestation became more active in the susceptible cultivar as regards the gene H1 and in the resistant cultivar, regarding the gene Gro1-4. In the nematode-susceptible cv. Nevskii, the level of infestation decreased and cold resistance increased, apparently indicating cross adaptation to two factors of different nature.