Studies On Enzymology And Ultrastructure Of Rice Leaves Inoculated With Magnaporthe Grisea And On Karyotype Of M.grisea

The interaction system of rice and Magnaporthe grisea is a model system to study the interaction between plant and pathogens. Materials used are typical rice varieties and typical physiological races of Magnaporthe grisea. i.e. Kanto 51 (immune to race 007, but susceptible to race I3I) Yamabiko (resistant to race 131, but susceptible to race 007 ). lshikari-shiroke (moderate resistant to race 131, but susceptible to race 007) and 007 131, two physiological races of Magnaporthe grisea. The changes of LOX POG activity and the ultrastructure of rice leaves in the different varieties at different space-time after being inoculated with the two races are systematically studied for the first time in order to elucidate the interaction mechanism of rice and rice blast disease. It is analyzed by CHEF (contour-clamped homogeneous electric field) that electrophoretic karyotype of the two races of M grisea for seeking after the heredity differences on chromosome DNA. All of these studies are helpful to deepen the research on the interaction between rice and rice blast pathogen. They will be beneficial to the location and the clone of the non-specific resistance genes of rice induced by the pathogen and its virulent genes, and finally to the reconstruction of the virulent genes and rice breeding for durable resistance to the disease by recombination DNA. The studies are of momentous significance both in theory and in application. 1. The changes of LOX (Lipoxygenase) activity in rice leaves induced by Magnaporthe grisea In the fifth leaves of rice, LOX Activities in R combinations are induced to rise by inoculated with M grisea at no more than 24h 24-36h and more than 36h respectively in Yamabiko.. Kanto5l and Ishikari-shiroke, and are up to peak at 60h. But there is a little increase in S combinations only at 60-72h after inoculation. Among the R combinations, the activity of Yamabiko remains the biggest all the way, but it's almost equal in Kanto 51 to that in lshikari-shiroke. The activity in the R combinations is 150% to 270% more than that in the S combinations, and is 2.9 to 5.3 times of that in the mimic inoculation. The symptom shows that Kanto 51 is immune to race 007 because it is resistant to the invasion of the pathogen, and that Yamabiko and Ishikari-shiroke are resistant to the extension of the race 131. In S combinations, the middle parts of LOX activities are the biggest and the base parts are the lowest in the three parts of the fifth leaves; the activity of fourth leaves is higher than that of the fifth leaves, but is lower than that of the fourth leaves in R combinations. This indicates the fourth leaves in S combinations are resistant to M. grisea at some extent. The LOX activity of rice leaves may be induced to rise by the infection of M. grisea. The stronger is rice variety to the disease, the shorter is the time after inoculation. LOX activity is not directly proportional to the resistance of the variety, but is correlation to varieties'resistance to extension of the pathogen. LOX activities induced are related to the number of cells infected with the pathogen and related to the parts and to age of leaves. The fourth leaves in S combinations become resistant to M. grisea with aging. 2. The changes of POG (Peroxygenase) activity in rice leaves induced by Magnaporthe grisea P06 activity in the fifth leaves-, the fourth leaves and the three parts of all three varieties is induced to rise as LOX after inoculated with IL'. grisea. It rises anteri...