Victoria Lavrova is a researcher at laboratory for Animal and Plant Parasitology in Institute of Biology, Karelian Research Centre of Russian Academy of Sciences. Research interests are interactions between cyst-forming nematodes (Globodera rostochiensis, Globodera pallida) / root-knot nematode (Meloidogyne incognita) and their host plants: phytonematode biology and development, plant responses and resistance/susceptibility to the nematodes (morphology, physiology, defense-and resistance genes expression); Innate and induced resistance of plants; Priming of plant immunity. Technical skills in Plant Biology and Nematology. Participation in professional development courses and training seminars.
Monoculture of potato as an important and widely distributed food crop is very sensitive to diseases. One of the most serious potato pest is potato cyst-forming nematode Globodera rostochiensis Woll., a subject for strict quarantine regulations over the world. The immune system of plant-host has significant influence on plant-parasite interactions (compatible or incompatible) and, accordingly, on plant resistance/susceptibility to diseases. Phytoimmunity is based on the effective detection of parasite effectors and rapid induction of defense responses. In this study the effect of immunity system of resistant (cv. Krepysh), susceptible (cv. Nevsky) varieties and plants pre-treated with temperature (temperature drop from 23 to 5°С for 2 h at the end of the night period during 6 days before nematode infestation) on juvenile development inside the potato roots was investigated. Results have shown that resistant plants accumulated transcripts of R-genes (H1, Gro1-4) at pre-invasion stage. During the nematode invasion levels of R- (H1, Gro1-4) and PR-genes (PR1, PR2, PR3, PR6) transcripts were up-regulated. These plants have possibilities for rapid activation of defense responses to juvenile’s penetration into the roots. As a consequence, females of G. rostochiensis have a reduced multiplication rate. The situation was different in a case with susceptible potato plants, which have inactive R-genes (H1, Gro1-4) and low transcript level of PR-genes (PR1, PR2, PR3, PR6) prior and during nematode invasion. The lack of possibility of plants timely recognize the nematode attack lead to very slow formation of defense responses to subsequent juvenile’s parasitism. So, nematodes had favorable conditions to developing and complete their life-cycle, and reproductive capacity of G. rostochiensis was maximal. Susceptible plants pre-treated by temperature had the similar traits with resistant ones. R-genes were expressed at pre-invasion stage that allows recognizing nematode effectors on time, rapidly generating strong signal for enhanced transcript abundance of PR-genes. At the same time transcripts level of Pel-1, Eng-1.4, Cle, SPRYSEC-1, VAP1, Tpx, Gpx in nematode tissues were down-regulated. These juveniles were limited in formation of syncytium and exposed to the defense responses of the plant-host. Development of the juveniles occurred in unfavorable conditions and was accompanied by a disruption in the reproductive function of females: the number of eggs and juveniles, and egg’s viability were reduced. Thus, resistant, susceptible and temperature-treated susceptible plants have differences in transcription profile of R- and PR-genes that is reflected on the timing of defense responses. This allows identifying the main mechanisms of plant resistance and susceptibility. Pre-treatment (daily short-term temperature drop) modulated the expression of genes in susceptible plants and enhanced their resistance to the invasion and suppressed nematode development. The relationships between nematodes and temperature-treated susceptible plants are defined as incompatible. The study was carried out under state order (№ 0221-2014-0030) and supported by RFBR (№16-34-00650).