|Stipanovic, Robert - Bob|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 6/28/2005
Publication Date: 8/15/2005
Citation: Veshkurova, O.N., Stipanovic, R.D., Arzanova, I.A., Pshenichnov, E.A., Sultanova, E.M., Uzbekov, V.V., Salikhov, S.I. 2005. Search for indigenous species of Malvaceae resistant to fungal diseases [abstract]. Proceedings of the 6th International Symposium on the Chemistry of Natural Compounds. p. 137.
Technical Abstract: Fungal diseases in cotton cause appreciable lose in the yield of cotton every year in all cotton cultivation countries including Uzbekistan. Biosynthesis of phytoalexins is one of the active defense mechanism of plants against pathogen attack. Phytoalexins from indigenous species of plants that are resistant to phytopathogens may synthesize more potent phytoalexins. Introduction of the genes for the synthesis of such active phytoalexins in cotton may increase resistance to fungal pathogens. In this paper we investigated the resistance of several members of the Malvaceae family including Hibiscus trionum, H. esculentus, H. manihot, Malva sylvestris, M. moschata, M. bucharica, Abutilon theophrasti and Althea rosa to the pathogens Verticillium dahliae and Fusarium oxysporum f. sp. vasinfectum. Our hypothesis was that resistant species would produce more active phytoalexins, and produce them more quickly. Our investigation indicates that the most resistant Malvaceae plants are H. trionum and H. esculentus. The phytoalexins in these plants achieved a maximal level within 24 h after inoculation by pathogens spores. Total phytoalexins were extracted from stems after inoculation, and phytoalexins were isolated by chromatography on silica column and further purified by HPLC. The toxic activity of individual phytoalexins was tested on fungi and their IC50 values were measured. Structure elucidation of the most active phytoalexins are underway. Identification of these compounds and the genes that regulate their biosynthesis could add novel tools to enhance resistance to cotton.