Analysis Of Infection Competition Of Sporisorium Reilianum And Fusarium Graminearum In Maize And Research Of Antifungal Mechanism Of Penicillium Minioluteum ZF1

Maize is the most important crop which is used for food and feed. It is about 40 percent areas in 3 provinces in Northeast and Inner Mongolia of China. Corn acts as an important role in agriculture in Northeast of China. Stalk rot and head smut are concerned in recently years with the change of planting pattern. Mechanized harvesting required a strict level, including lodging resistant variety and ears of no pathogens. Research of controlling stalk rot and head smut is placed a key position. This research depends on the results of resistance level of maize in the field by the inoculation to select testing maize cultivars. The change is deeply known for competition of Sporisorium reilianum and Fusarium graminearum in maize by PCR and fluorescence staining. The results are used to actively guide disease resistance breeding and adequate distribution of cultivars. In the meantime, Penicillium minioluteum ZF1 was isolated from the soil and identified as having the effect of biological control in previous studies. The objective of this study is to analyze the inhibition effect of the isolate and seed coating agent of culture filtrate with chemical fungicide to F.graminearum and S. reilianum, and to offer a novel method for controlling the stalk rot and ear rot which caused by F. graminearum and S.reilianum. The main results are as follows:1. Resistance level of 1000 corn breeds was measured to head smut and stalk rot.14 breeds susceptible head smut or stalk rot were found. There were not found classical symptom of head smut and stalk rot in the same plant. Fluorescence staining and Confront culture were used to study the Mechanisms of competition of S.reilianum and F.graminearum in maize. Teliospore germination of S. reilianum was lower which the plant was inoculated F. graminearum and 5. reilianum together than only inoculated S. reilianum. Mycelia of F. graminearum were also growing slowly in the plant which inoculated F. graminearum and S. reilianum together. It was speculated that competition between F. graminearum and S. reilianum furthermore suppress exudates of F. graminearum and S. reilianum each other in growth.2. Spore germination and mycelial growth of F. graminearum in S.reilianum zymotic fluid and teliospore germination of S. reilianum in F. graminearum zymotic fluid were studied. The results showed that spore germination and mycelial growth of F. graminearum in S. reilianum zymotic fluid was inhibited. As time went on, the effect of S.reilianum zymotic fluid to spore germination and mycelial growth of F. graminearum was not very obvious. Teliospore germination was powerfully inhibited in F. graminearum zymotic fluid, and can not germ. That is to say, teliospore germination was limited by metabolic product.3. GSP1/GSP2, TEF-1αSF/TEF-1αSR and FG1/FG2 are screened from 7-double primer pairs. GSP1/GSP2 and TEF-laSF/TEF-laSR are used to specific amplify targeted region of S.reilianum, and FG1/FG2 are used to specific amplify targeted region of F.graminearum. The minimum detectable concentration of F. graminearum DNA was 2×10-4ng·μL-1 by FG1/FG2 primers. Detection Techniques of F. graminearum and S.reilianum were established in early stage. PCR technology was used to screen different symptom plants. It was found that only F. graminearum DNA in withered plants can be detected. The results showed that F. graminearum did not reach nodes in seedling stage.4. The leaves and kernels were inoculated with P. minioluteum on 146 maize cultivars. Slight mold appeared in injured maize kernels and seedling leaves when P. minioluteum was inoculated P. minioluteum as a biocontrol fungus be used on maize is safe. P. minioluteum can also promote the absorption of nitrogen.That P. minioluteum with 0.1g or 0.3g nitrogen be used together can improve 7.4% and 4.5% compared with only used 0.1g or 0.3g nitrogen. The plants look strong and nodes become thicken, and also improving resistance level.5. P. minioluteum can also restrict the spread of fungi hypha. F. graminearum was inoculated at the mixed PDA media and the growth speed was calculated. P. minioluteum ZF1 obviously inhibited the mycelial growth of F. graminearum. The inhibition ratio reached 81.3%. The area of inhibited mycelial growth of F. graminearum was 16.21 cm2 compared with the control groups. The effect of secondary metabolite of P. minioluteum was inoculated on PDA media removed cellophane which inhibited the mycelia growth of F. graminearum reached 55.5%. The filtrate of P. minioluteum which were diluted 50 folds inhibited the growth area of mycelia of F. graminearum were 22.7%. The mycelia of morphology were not changed when ZF1 culture filtrate was added in PDA media.6. The mixture of chemical fungicide and culture filtrate of P. minioluteum could decrease the occurrence rate of stalk rot. The mixture of fludioxonil and 10% culture filtrate of P. minioluteum had the better effect than each single. The EC50 and EC95 values of fludioxonil to F. graminearum were 0.0162 and 0.5287 μg·mL-1, respectively. The inhibition ratios of 10% culture filtrate of P. minioluteum and 0.5 μg·mL-1 fludioxonil were 86.5% and 95.1%, res·pectively. EC50 and EC95 values of the two mixtures were 0.0023μg·mL-1 and 0.4011 μgmL-1 respectively. The effect of fludioxonil inhibition disappeared from the 4th day. The inhibition effect of the mixture of 0.5 μg·mL-1 fludioxonil and 10% culture filtrate of P. minioluteum prolonged for 10 days compared with only 0.5 μg·mL-1 fludioxonil.7. P. minioluteum could decrease the occurrence rate of head smut.The occurrence of head smut reach 62.3% when Huangzaosi was inoculated S.reilianum, and the occurrence of head smut only reach 24.5% when P. minioluteum granules was used with S.reilianum. The results showed that P. minioluteum ZF1 granules could be used to control head smut.