Relationship Between The Catalase Activity And Tobacco Resistance To Cucumber Mosaic Virus

After tobacco seedlings are inoculated by cucumber mosaic virus (CMV), the activity of catalase (CAT) will change subsequently, what's more, the change is distinct in cultivars with different disease resistance. And there are defeats in the disease identification, such as the index of state. If there are relationship between the catalase activity or the changes of catalase activity and the resistance, it can be regarded as physiological index to identify disease resistance, and that can conquer the defeats of conventional disease identification. In this report, tobacco cultivars with different disease resistance were discussed, determined the catalase activity of tobacco seedlings before and after the inoculation of CMV, meanwhile investigated the state of CMV. Our aim is to analyse the catalase activity and state of cucumber mosaic virus bidirectionally, to find the rule of their relationship, and to see if we can use the catalase activity as index to forecast the disease resistance of other tobacco cultivars. The results are as below:1 There are no specific rule between the disease resistance of tobacco cultivars and the change of catalase activity, the change of catalase activity may be different in the tobacco cultivars belongs to the same level of disease resistance, vice versa. So it's not feasible to study the change of catalase activity of one cultivar, and based on these study the possible change of cultivars about the same resistance, and the article suggested that comparison of the cultivars with the same genetic background maybe a possible solution, of course, this still need to do more genetic analysis, both in traditional and molecular approach.2 The disease resistance is negative to the catalase activity in the healthy seedlings and in the diseased ones eight days after the inoculation, that's to say, the higher the catalase activity, the higher the state of CMV will be, and the weaker the disease resistance will be, correspondingly, the results proved the physiological function of catalase.3 Using Data Progress System, we analysed the pertinence of the catalase activity in the tobacco seedlings and the index of state of CMV. The results indicated that the correlativity between the catalase activity of the healthy tobacco without any disposal and the state of CMV is marked, meanwhile the the correlativity between the catalase activity of tobacco eight days after inoculation with cucumber mosaic virus and the state of CMV is marked, too. We can use them as the physiological index to identify the disease resistance of tobacco directly.4 But as we all know, the state of illness and the catalase activity is infected by many factors, so the direct use of the regressive equation is limited, so we emendate the equation making use of two consult cultivars, and the result of forecast is perfect.5 There is no significant linearity correlation between the change of catalase activity and the index of state of disease, which is mostly anticipated as correlative.