Danilova O. Viruses and viral infection of tomato plants of open ground under the forest-steppe of Ukraine

Dissertation is dedicated to investigation of viral disease of tomatoes (Lycopersicon esculentum Mill.) in four regions of forest-steppe zone of Ukraine. Symptom of this disease was rolling of leaves upwards, before undeclared in Ukraine. Viral etiology of the disease is proved and it is identified its causative agents - Potato virus M and Potato virus Y. It is the first report about infecting of tomato plants by the indicated viruses in Ukraine. It is set that the mixed infection of PVM and PVY has most part in infecting of tomato plants. It is shown that frequency of exposure of PVM in tomatoes with the marked symptoms of diseases higher than frequency of PVY detection. Some of morphological, biological, chemical and physical properties of isolated viruses are studied. Differences in the range of indicator plants and molecular weight of structural proteins of tomato isolates PVM and PVY in comparing to other tomato and potato strains were revealed. Phylogenetic analysis of nucleotide and amino acid sequences demonstrated high level of phylogenetic relationship between the Ukrainian isolate of PVM and three strains of Euro-Asian group - Iranian, German and tomato Italian. The substantial decrease of concentration of carotenoids lycopene and beta-carotene in tomato fruits at viral infection is shown. Four cultivars of tomatoes are recommended, as sources of resistance to PVM and PVY. The alternative methods of tomato plants defense from viruses is worked out.