Variety Identification And Molecular Detection Of Gaeumannomyces Graminis Of Wheat In Henan

Wheat take-all disease is the devastating disease on wheat production, whichspread through soil. Since1992in Junxian, Fugou, Yuanyang county of henanprovince found that wheat take-all disease, the disease in the occurrence and harm ofhenan province showed a trend of increase year by year, is the present outbreak in theprovince in recent years, seriously affected the safety on wheat production in henanprovince. Although the identifieation and Physiologieal characteristics in G.graminiswe studied,the variation of Pathogeuleity,diversity of the PoPulation, andPhylogenetic of the population, and phylogentic of the G.graminis from henanProvince have not carried out,here we conducted the works in these fields and themain results are following.1、Hammered out the main species of pathogenic bacteria of Wheat take-all disease. Inorder to unravel the occurrence of the pathogen in Henan Province, samples showingtypical symptoms were collected from nine regions including Kaifeng, Xinxiang,Puyang, Guxing, Shangqiu, Zhoukou, Zhumadian, Jiaozuo and Jiyuan and89Gaeumannomyces strains were isolated from them. The colour of the colony was hoarduring the early stage and then changed to taupe at the late stage on the PDA medium,the margin was curled to the center. Ascus was Induced by PD triangular flask method.By measuring the size of ascus, ascus spore, adhesion and conidium found that thecharacteristic of which were very similar attached with Gaeumanomyces graminisvar．tritici. So reliminary confirmed thise pathogens of Wheat take-all diseasein henan province were Gaeumanomyces graminis var．tritici.The primers designedby Rachadwong and Wang Meinan were used to identify the89strains.The resultsindicated that only the870bp fragment of Ggt was amplified, no other specificfragments obtained.By using the fungi universal primer ITS4and ITS5, the ribosomalDNA internal transcribed spacer (ITS) region of the genomic DNAs was amplified,sequenced, and analyzed using MEGA5.2software. The result of the clustering andanalysis showed that all89isolates and6representative species of Ggt’s sequencesfrom GenBANK were clustered together and showed close genetic relationships.89 isolates can be separated clearly from other varieties. The research results of abovetwo kinds of molecular technology conform to that of morphologicalidentification.Further proves that all strains are Gaeumanomyces. Graminis vartritici.2、Cleared the pathogenic of bacteria to major crops and weeds in the field of Henanprovince.Useing Grain of sand to test the pathogenicity of Gaeumanomyces graminisvar．tritici, the host including: oats,rye, corn, soybeans, peanuts, cotton. The resultsshowed that most strains can attack the gramineous crop, lead to the root tissuenecrosis or decay, similar to wheat take-all disease symptoms, individual strains cancause oat root and stem base slightly brown. Peanuts, soybeans, cotton root brown justlocal time, pathological changes of rhizome tissue after purification by wheat take-alldisease, show that the symptoms are caused by it. Sand of grains was employed to testthe host range on the main weeds in the field of Gaeumanomyces graminis var．tritici,the selected plants including gramineous weed, huwei grass, horse pond, greenbristlegrass, teff, pennisetum, goose grass etc; cyperaceae: Cyperus rotundus;Compositae: chrysanthemum yellow top, bitter radicchio dishes; Broad-leaved: cowchickweed, abutilon, carp intestine, amaranthus retroflexus, humulus scandens, purpleamaranth, Bian storage, xanthium sibiricum, amaranth flowers etc. Results show thatin addition to weed and mans tares showed no symptoms, stem base and other weedsroot all have different degrees of black brown, especially gramineous weeds showsymptoms similar to wheat take-all disease symptoms, the total eclipse of theseparation and purification were wheat germs.3、The virulence of Gaeumanomyces isolates showed significant difference, andGaeumanomyces isolates in Henan Province.Determination of pathogenicity，89strains of wheat in greenhouse showed that, there was a significant difference betweenthe pathogenicity between isolates from different strain of the in the same area anddifferent regions。Determination of pathogenicity on corn，the result showed that thetop grain capsule shell wheat varieties pathogenic render continuity and changes inthe corn, by not pathogenic to strong pathogenic, and pathogenicity between strains indifferent areas exist significant differences, in the same area between different strainsof pathogenic force there is also a very significant difference, that top nuclear capsuleshell wheat varieties in corn on pathogenicity differentiation. 4、Optimized for fast detection method of wheat take-all disease. Though validationthe primers Ggt：AV3which Released by Wangmeinan and Zhang Qiue etc,and theoptimization of the PCR reaction system further, set up a system of rapid detection ofwheat take-all disease. This method can directly detection Ggt from the wheat roots,and the primer can be used for different level of wheat root detection. With theincrease of the degree, the width of the stripe and brightness were increased,indicating that the primer can be used in wheat take-all disease early diagnosis andprediction.