Chrysanthemun White Rust Integrated Control And Resistance Genes Cloning From Chrysanthemum Morifolium Ramat

The white rust, caused by Puccinia horiana Henn, is one of the most important epidemic diseases on chrysanthemum, and also is a quarantine action pest in the world. P. horiana. has been discovered in Japan since 1895, but was first described taxonomically by Hennings in 1901. The disease spreded worldwide along with the cuttings and potts of chrysanthemum products, which caused a great economic loss to the growers. The chrysanthemum white rust has been spreding in China recent years, which has become the limiting factor of cut chrysanthemum production and chrysanthemum field production. There are profuse cultivars of chrysanthemum in China and they have different responses to P. horiana. Therefore evaluation and identificateion of chrysanthemum cultivars'responses to P. horiana, and in search of the related resistance genes are all of great importance in chrysanthemum resistance breeding, as well as promoting development of chrysanthemum industry.Typical symptom of chrysanthemum white rust was observed on chrysanthemum plants inoculated by the pathogen: yellow pustules were found on the underside of leaves. The pathogen in this research was taxonomically describpled as P. horiana.Trials determined the teliospores germinating biology of P. horiana to provide basis for control teliospores germinate in order to avoid the disease, by the way of adjusting ecology environment. The major influencing factors on teliospores germination were temperature and water. The teliospores were germinated between 4℃and 32℃, while the optimum temperature range was 15℃to 24℃, especially between 18℃and 21℃. Water was necessary for the teliospores germination. Without free water, it couldn't germinate in 24h, even with 100% R.H. The propriety of pH for germination was pH 4 to 6.5, while pH6 was the most favorite. These results provided the basis for prevention of chrysanthemum white rust by regulations of leaves'micro-environment. On the basis of investigation of P. horiana overwintering and oversummering regulations in Beijing area, it made clear that P. horiana couldn't survival in Beijing's winter and was inhibited in summer, which provided the basis for control the disease in Beijing. The effectiveness of chemical compounds as preventively applications and curatively applications in the control of chrysanthemum white rust were tested. The result showed that Difenoconazole 4000-fold plus Mancozeb 1200-fold, Chemical A plus Chemical B X-fold, Polyram 800-fold, JuBingbizhi 500-fold, Pisen 1500-fold and Triadimefon 1000-fold in preventively applications and Diniconazole 3000-fold plus Pisen 2000-fold, Flusilazole 10000-fold, Diniconazole 3000-fold plus Mancozeb sulfur 600-fold, Myclobutanil 8000-fold plus Mancozeb 1200-fold, Diniconazole 3000-fold, Difenoconazole 3000-fold plus Mancozeb 1200-fold, Azoxystrobin 3000-fold in curatively applications were more effective. Besides, infected cuttings were treated with chemical compounds, which aimed at cutting off the source of infection from infected cuttings.On the basis of the above study, integrated measures to control chrysanthemum white rust was provided including putting prevention first, strengthening quarantine, adjustment of cultivation measures and controlled by chemicals.The rust-resistance was investigated among 47 chrysanthemum cultivars, and 27 of these were fond out with resistance to the disease, among which 9 were free off invagation. cDNA amplified fragment length polymorphism analysis(cDNA-AFLP) was used to disply transcripts whose expressions is rapidly altered during the interaction of chrysanthemum and P. horiana. There were 18 P. horiana induced fragments (PIF) aquired which were homology sequences related with plant resistance, and these PIFs were belonged to 7 groups: disease resistance protein, receptor-like protein kinase, molecular chaperone protein, photosynthesis and photorespiration, retroelement polyprotein-like, senescence and other metabolism pathways. Molecular chaperone protein was the lagaest group of the 7 groups, which may play more important role in chrysanthemum resistance. In summary, P. horiana induced resistance involves many processes of plant biochemistry and physiology and are controlled by multi different genes in chrysanthemum.