Hypersensitive Cell Death And The Mechanism Of Resistance To TMV Induced By AT-toxin

Hypersensitive cell death (HCD) happens when the plant is invaded by non-relative pathogen.It is so called hypersensitive response (HR) .HR is considered as an active response to the outside stimulation.The dead cell can acquire local resistance by limiting the pathogen.The toxin is a secondary metabolizable production in the pathogenic process of many pathogens,which can cause necrotic spot of the host. So it is a poisonous factor and it is important to the pathogenic activity.Many people regard that the cell death which is caused by toxin has essential difference with necrosis.But there is not enough research of this cell death.This dissertation uses AT-toxin as material and we have done the reseach of the character of cell death and the mechanism of resistance to TMV which is induced by this toxin.The aim is to make it known whether there is relation between necrosis and HR or not.The results as follows:1. Purification and analysis of AT-toxinFirstly, we detected the components of protein and nonprotein, the results showed that AT-toxin is a nonprotein. We have carried out the liquid chromatogram analysis of the toxin. The result indicates that there are many components in this toxin and there are four kinds of components which content is more than others. At last, we have the experiment of separating the cpmpositions with the silica gel and we get four components which are active.This result showes that there are many components in this toxin, and the components have something to do with each other.2. AT-toxin has effects on physiological activity of tobacco leavesAT-toxin can induce typical symptom on tobacco leaves, such as fading of treated position and cell death. In order to testify whether this toxin can affect the physiological activity of tobacco leaves or not, we study this from two parts: at first, we detect the content of chlorophyll, the result showes that the cotent of treated leaves is fewer than the control. At the same time, we test the effect of this toxin on photosynthesis and the result indicates that...