Mechanism Of Induced Resistance To Cucumber Fusarium Wilt By TBTC(1,2,3-Benzothiadiazoie-7-Carboxylic Acid,2,2,2-Trilfuoroethyi Ester)

Cucumber wilt (Fusarium oxysporum f.sp. cucumerinum, FOC) is a serious soil-bornedisease in cucumber planting, which restricted the development of protected cucumbercultivation. At present, the main methods in controlling the diseaset are grafting, soilfumigation and root irrigating with fungicides. However, all these methods were extremelylaborious and time-consuming. In this thesis,1,2,3-benzothiadiazole-7-carboxylic acid,2,2,2-trifluoroethyl ester(TBTC), a new activator for plant diseases, was synthesized in EastChina University of Science and Technology with independent intellectual property rights.The objectives of this study were to investigate the induction activities by TBTC radiclesoaking and foliar spraying at different concentrations, to microscope the transportation traceof N-TBTC with fluorescence and in situ detection of TBTC, to depict the mechanisms ofphysiological and biochemical processes after TBTC induction and real-time PCR detectionfor FOC. The innovation of this dessertation was that a new technique for controllingsoil-borne disease by foliar spraying was confirmed, and the biochemical and molecularmechanisms were clarified, which would promote the conmmercialization of TBTC in thenear future. The results were as followings:1. The induced resistance spectrums on major crops disease in five kinds of crops wereshown by TBTC. It exhibited good induced resistance effect (65%~90%) againstPseudomonas syringae pv. tomato, Fusarium oxysporum f.sp. cucumerinum, Pythiumaphanidermatum, Sclerotinia sclerotiorum, Phytophthora capsici, tobacco mosaic virus.2. In all these fungal, the TBTC displayed excellent activity against Fusarium oxysporumf.sp. cucumerinum. In the further experiment, no fungicidal activities were found for TBTCin vitro experiment, and it could induce cucumber to produce obvious aquired resistance to FOC. The best induced resistance of TBTC was combination technology at the concentrate of100mg/L or50mg/L. The maximum induced resistant effect was shown when cucumberwere treated by radicle-soaking30min and foliage spray, whose average aquired resistancewas85.71%. When it was treated at100mg/L and50mg/L, the average aquired resistancewere96.13%and87.16%, respectively. The effect of induced resistance was furtherconfirmed to FOC in field, which was62.05%.3. Base on the organization structure, the mechanism of induced disease resistance wasrevealed. It can inhibit the root infection by FOC. The deposition of major secondarymetabolites such as lignin, callose, and phenolic compounds were increased in2days afterTBTC induction in stem, root and leaf of cucumber, especially in root, which raised the abilityof cucumber against infection. Simultaneously, along with the induction time extended, thecontent of tyrosine-rich hydroxyproline-rich glycoprotein (HRGP) and the activity ofpathogenesis-related (PR) protein-β-1,3-glucanase exhibited an initial fast increase followedby a reduction after TBTC induction. The content of H2O2in cucumber organizations wasdifferent as the time variation in different leaves after induction. The content of H2O2in upperleaf was higher than lower leaf if the middle leaf was induced.4. The mark technology showed that the TBTC was transfer from leaf to root in4hafter foliar spray at seedling stage. Push-pull electronic system was formed by introducing thedonating group-NH2at5-position of TBTC. Although the electronic of N-TBTC was easilystimulated at wavelength384nm to send fluorescence, the aquired resistance (64.42%) were stillacceptable to FOC in field. After foliar spraying, strong fluorescence signal can be detectedby fluorescence microscope in root tissue from4h to24h. The function of induced resistancewas stronger downward than upward, which was a stronger evidence of cucumber resistant tothe infection of FOC. 5. In order to detect the quantity of FOC in induced soil and plant by TBTC, real-timePCR detection technique was established according to FOC ITS region sequence specificprimers FOF1/FOR1. At the same soil depth, the inocula and disease index were decreasedwith the increasing of TBTC concentration at10mg/L~50mg/L.6. The relationship between induced resistance effect and rhizospere inocula of FOC wascorrelated by real-time PCR and selective culture media. With the concentration increasing ofTBTC, the quantity of FOC decreased in cucumber root and soil. There were4.65×104spores/g root tissue at25mg/L of TBTC and4.58×104spores/g soil sample in rhizosphere. Whileit were1.93×103spores/g and2.58×103spores/g soil sample for TBTC at50mg/L.In conclusion, the control efficiency of TBTC to Cucumber wilt and the condition offield application were depicted in this thesis. The absorbtion and transportation process fromleaf to stem and root by spraying on leaves and induced resistant mechanism of organizationalstructure were clarified as well. This paper put forward a new approach that controlledsoil-borne diseases of vegetables by foliar spray. On the other hand, it has an importantpractical significance to accelerate TBTC with independent intellectual property rights toserve agriculture.