Studies On Induced Maize Disease Resistance By Bipolaris Maydis RaceT Toxin And Salicylic Acid

Many plant breeders and agronmists have considered that plant disease by aroused pathogenic microorganism is a focus in their research since the initiation of cultivating crops. Inducing the Systemic Acquired Resistance(SAR) has already been available to control the disease. The elicitors can elicit special responses to plant disease denfence, which is an active topic of in the plant pathology field. It possesses an unipue advantage: elicitors can induce some special responses in plant and then efficiently cause the plant much resistance to disease. On the contrary, to breed and identify a cultivar of crop with stronger disease-resistance at least requires several years and the environmental pollution is often caused by the fungicide prevention. In practice, using biological factors and chemical factors have acquired a lot of achievements on Induction of SAR in melons, tobaccos, beans, potatos and rice.To study the role of salicylic acid and some diffusible biological factor are an active topic recently. The main components for ISR including low molecular weight polysaccharide, glycoprotei^ low molecular weight polypeptide are diffusible. We used T-toxin, a linear polyketon, as the biological factor in our experiments. T-Toxin as biological factor is creative. My esperimental results are devided into four parts.Firstly the resistance to maize southern leaf blight can be induced by the low concentration filtration of Bipolaris maydis race T cultivation. At the same time, we determined the changes of Peroxidase, phenylalanine, ammonialyase, Malondialdenyde activities. Accordingly, it is accouted that the low concentration filtration of Bipolaris maydis race T cultivation may be used as an elicitor which enhances the disease resistance of maize.Secondly the maize disease resistance can be induced by the low concentration Bipolaris maydis race T toxin. But the protein extraction and the cell wall extraction can't do. At the same time, we measured the dimesion of the leaf spot and determined the changes of PAL (Phenlanine ammonialyase ) activities. Accordingly, it is accouted that the low concentration of Bipolaris maydis race T toxin may be used as an elicitor which enhances the disease resistance of maize.Thirdly on the bases of above experiments, we detained the same results on CMS-TB37 and CMS-TMo17 lines, as well as CMS-TC103 line did, So the low concentration of Bipolaris maydis race T toxin as an elicitor is extensive and can be repeatable.Finally salicylic acid was applied in my experimental system. It was found that this chemical only could alleviate the invasion process ofBipolaris maydis race T and was unable to induce related SAR in Maize.Taken together, It was found that the diluted filtrate of Bipolaris maydis race T culture, especially the race T toxin, could enhance the disease-resistance of maize. To explore how the race T toxin play a role of elicitor in Maize would be very important theoretically and practicably.