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Variability of the biotrophic fungus Puccinia. graminis Pers. f.sp. tritici on different host plantsтезисы доклада
- Авторы: Lekomtseva S.N., Skolotneva E.S., Maleeva Yu V.
- Сборник: XV Congress of European Mycologists. Saint Petersburg, Russia, September 16-21, 2007. Abstracts
- Тезисы
- Год издания: 2007
- Место издания: TREEART LLC Petersburg, Russia
- Первая страница: 259
- Последняя страница: 259
- Аннотация: Parasitic fungi need to keep up with the changeable environment, which is comprised of the natural environment and specific biochemistry and resistant systems of the host plant. Consequently, the genomes of the parasitic fungi evolved to be highly flexible. Stem rust – P. graminis f.sp. tritici (Pgt) is a dangerous pathogen that infects wheat and some wild grasses. This pathogen is distributed worldwide, including Russia. There is a great genetic variability within this special form P. graminis. Pgt was collected from barberry, wheat, barley and wild graminaceous species in various regions of Russia between 2001 and 2005. 309 monouredinial clones were isolated and multiplied on sensitive wheat cultivar. The Shannon diversity index (Shannon’s index) was used to evaluate diversity of race composition of populations depending on the season, host plant and geographical zone. In 2001-2005 race composition of Pgt was found to be very diverse. 43 pathogen races, 2-3 of which dominated annually, were identified during this period. Frequency of other races was less than 8%. We classified these races as rare. The percentage of rare races varied from season to season. The highest diversity of fungal races was observed in 2001-2002 seasons which were relatively favorable for the development of wheat stem rust pathogen. Evaluation of race composition on various host plants in Central Russia (Moscow region) revealed that Pgt clones obtained from barberry were most diverse. Our results suggest that the sexual process contributes to the diversity of Pgt in this region as well as to the variability of race composition on wild cereals. Race composition of the wheat corns is poor due to the domination of highly virulent races. Using isozyme and randomly amplified polymorphic DNA (RAPD – DNA) markers we performed a complex analysis of Pgt isolates from various grasses and barberry. Pgt isolates collected in 2003 were clearly segregated into three groups: from barberry and from Triticae (Elytrigia and Hordeum). RAPD – DNA analysis showed that the genotypes of isolates collected from barberry in 2004 (Central Russia) were clustered into the distinguished stable (by index bootstrap up to 94%) group. However, by contrast with the RAPD-data, clusters of the MDG-phenotypes of the “barberry” isolates were more strictly opposed to the groups of isolates from grasses, probably due to the functional differences between these markers. MDH-polymorphism analysis revealed a geographic variation among the isolates collected from different grasses. On the other hand, RAPD-profile – based grouping of Pgt isolates was independent of their geographic origin. The host plants determined the structure of RAPD-diversity. These results could suggest there are several trends of Pgt variability on the molecular level.
- Добавил в систему: Малеева Юлия Владимировна