Submitted to: Cellular and Molecular Biology of Soybean Biennial Conference
Publication Type: Proceedings
Publication Acceptance Date: 12/10/2002
Publication Date: 12/31/2002
Citation: LOZOVAYNA, V.V., LYGIN, A.V., ZENOVA, O.V., ULANOV, A.V., ANDRES, A., LI, S., HARTMAN, G.L., NELSON, R.L., WIDHOLM, J. SOYBEAN PHENOLICS (ISOFLAVONES AND LIGNIN) AFFECTING SEED QUALITY AND ROOT RESISTANCE. CELLULAR AND MOLECULAR BIOLOGY OF SOYBEAN BIENNIAL CONFERENCE. 2002. P. 601
Technical Abstract: In leguminous plants different classes of phenylpropanoid compounds play very important roles in defense reactions. Intense studies are focused on specific flavonoid and isoflavonoid compounds due to their antioxidant activity and potential benefit for human health. We are interested in three main aspects related to soybean phenolic metabolisms: 1) evaluation of the role of phenylpropanoid metabolism in the soybean root defense response to FSG infection; 2) determination of the effect of genetic and various environmental factors on the alteration in phenolic metabolism and accumulation of isoflavones in soybean seeds; 3) genetic manipulation of phenolic metabolisms to enhance health promoting value of soybean seeds and soybean plant disease resistance. The results will be presented indicating the alterations in phenolic metabolisms that are critical for soybean resistance to sudden death syndrome (SDS), caused by the soil-born fungal pathogen Fusarium so/ani P. sp. glycines (FSG). Considerable changes were found both in compounds of isoflavone and lignin branches of phenylpropanoid pathways with the phytoalexin glyceollin levels being much higher in partially resistant genotypes. Activation of lignin synthesis as a response to FSG infection was found in resistant but not in susceptible plant roots. Genetic modifications that could be effective in enhancing SDS resistance will be discussed. We found that the diversity of isoflavone concentration and composition in plant introductions either can be used for increasing or decreasing the current amount or changing the composition of isoflavones in U.S. cultivars. Information on the critical combinations of genetic and environmental factors that will allow for the production of soybean seeds with uniformly high or low isoflavone levels will be provided. The approaches used and the progress achieved in our genetic manipulation of isoflavones and cell wall phenolics will be presented.