3.4.55
IMMUNOCHEMICAL STUDY OF CHROMATIN PROTEINS IN MONOGENIC LINES OF WHEAT DIFFERING IN RESISTANCE TO STEM RUST

TP YURINA

Faculty of Biology, Moscow State University, Vorobjovy Gory, 119899 Moscow, Russia

Background and objectives
Non-specific plant resistance to disease is, in many respects, due to the active synthesis of various compounds taking part in plant-pathogen interaction [1]. Synthesis of these compounds depends on the peculiarities of host chromatin. The aim of this work is to reveal a difference in antigen composition of chromatin in monogenic lines of wheat differing in resistance to stem rust.

Materials and methods
Two monogenic lines of wheat cultivar Markiz were used in the work: Markiz Sr Tt (resistant to stem rust) and Markiz Sr 9B (susceptible to stem rust). Wheat plants were grown in a greenhouse at 18C under natural daylight supplemented with cool-white light. Electrophoretic analysis was carried out as described in [2].

Results and conclusions
Electrophoretic analysis of chromatin proteins showed more than 20 protein bands which included 4-5 main components with low and middle relative mobility. In comparison with the susceptible line, the resistant one had an additional 4043 kDa component. This component may evidently serve as a marker of resistance gene. We also revealed 8 antigens in chromatin of resistant line and 6 antigens in chromatin of susceptible line by the use of homologous antisera. Both lines had 4 similar antigens with low and high electrophoretic rates. There were some quantitative changes in correlation between different fractions during pathogenesis. We suggest that certain protein components of chromatin play a special role in synthesis of proteins whose contents probably change under the influence of pathogen.

Isozyme spectra of peroxidase in resistant and susceptible lines of wheat differed too. In particular, we revealed 10 protein bands in resistant line and only 8 in susceptible one. Serological analysis gave a similar result. Specific molecular forms-isozymes of peroxidase are, in their main part, the antigenic determinants. Possibly, the locuses which code these isozymes are bound with the resistance gene.

References
1. Rubin BA, Artsikhovskaya EV, Aksenova VA, 1975. Biochemistry and Physiology of Plant Immunity, Vysshaya Shkola, Moscow, 320 pp. 2. Solntsev MK, Karavaev VA, Ekobena HPF, Tashish V, Yurina EV, Yurina TP, 1996. Modern Fungicides and Antifungal Compounds, Intercept, Andover, pp. 257-62.