Induced Increase Regulation Of Cellular Cam Levels On Tobacco Disease Resistance And Related Antioxidant Enzyme

In this dissertation, Tc-inducible cytoplasmic CaM expression transgenic tobacco line T1.1 which was developed by our laboratory, and control line T2.3 were used as experimental material, to study the involvement of CaM in the regulation of the disease resistance as well as the relationship between disease resistance and related antioxidant enzymes.The present results included two parts:For the first part, line T1. 1 and T2.3 were inoculated with three different kinds of pathogenic fungus including tobacco mosaic virus Phytophthora parasitica van nicotianae and Alternaria alternata after different Tc treatments and their resistance were surveyed . The results indicated that, the CaM activity changes of control line T2.3 was not significant regardless of Tc induction in plants and excised leaves, similarly, disease percentage and disease index had not significant difference yet. CaM activity of transgenic tobacco line Tl.l after Tc induction was apparently higher than the untreated line and control line T2.3. Their disease percentage and disease index were lower than untreated line Tl.l and control line. These results indicated that, Tc-inducible rised the activity of CaM could enhance the disease resistance of tobacco.For the second part, we measured the CaM activity of Tl.l and T2.3 inoculated Alternaria alternator under Tc induction by phosphodiesterase. The results indicatded that, the CaM activity changed in variant degrees in two lines under two treatments. The CaM activity maintained higher level after inoculating one to two days, soon afterwards have different degree drop. In which, transgenic line Tl.l was induced and inoculated pathogenic fungus for one day, the rising range of CaM activity was less and its drop range was also less in soon afterwords time. On the contrary, Tl.l and T2.3 was induced and inoculated, the rising range of CaM activity is greater and its drop range is also greater in soon afterwords time as well as T2.3 was induced. Based on the results , we measured three kind of antioxidant enzymes(SOD CAT POD)involved in plant disease resistance. According to measure results, Tl.l line was induced by Tc, the activity of three kind of antioxidant enzymes were apparently higher than the same line whithout Tc induction and control line T2.3 regardless of Tc induction. Its tendency was similar to the CaM activity changes. The study indicated that, Tc-inducible rising CaM activity regulated three kind of antioxidant enzymes activity; pathogenic infection could initiate the changes of CaM activity as well as three kind of antioxidant enzymes activity. These results demonstrate that, the up-regulation of CaM level in tobacco can enhance tobacco disease resistance, and the effect is mediated by the regulation of CaM on the activity of antioxidant enzymes.