Induced Resistance To Plasmodiophora Brassicae In The Chinese Cabbage By Fluoro-substituted Benzothiadiazole Derivatives

Fluoro-substituted benzothiadiazole derivatives(FBT)can induce many kinds of vegetable against soil borne disease effectively, as well as in the Chinese cabbage caused by Plasmodiophora brassicae.The Chinese cabbage clubroot disease is a lack of a simple and effective method of prevention and cure for a long time.This article focus on the induced technology and method of FBT and the resistance mechanism in the Chinese cabbage.The main results are:1. Resistance of the Chinese cabbage against Plasmodiophora brassicae induced by FBT was investigated in this paper. Plasmodiophora brassicae spores treated with FBT was stained by Hoechest3342/PI,founding that the spores vitality was not influenced by FBT. The result of pot experiment showed that when we induced the Chinese cabbage with 25mg/L FBT 3 times at an interval of 7 days, the control efficacy was 71.33%, better than fluazinam(63.32%). Based on the result of field experiment, the control efficacy varied at an acceptable range for FBT, BTH and fluazinam. The highest control efficacy of FBT is 69.99% at 25 mg/L, in accord with the result of pot experiment. In this study, we established a application technology to control club root of the Chinese cabbage by surface spraying, providing a new control strategy for soil borne disease.2. FBT was investigated to determine the mechanisms of resistance against Plasmodiophora brassicae in Chinese cabbage. The leaves were pretreated by foliar spraying with FBT at different concentrations,disease severity was suppressed most at 25 mg/L. We stained the roots with trypan blue,found that the root colonization by Plasmodiophorabrassicae were significantly controlled after the leaves were treated with FBT. Analysis of defense-related genes by Real-time PCR showed that FBT excites the expression of SA-responsive PR-1 gene and JA-responsive COI1,LOX2 genes obviously,indicating that the JA-signaling pathway is essential for FBT-induced resistance in Chinese cabbage,including partial SA-signaling.3. FBT induced sysemtic reisitance in Arabidopsis. In order to confirm the signal pathway that induced by FBT, we sequence the mRNA of Arabidopsis treated with FBT. The result of GO analysis and KEGG pathway analysis showed that biological processes, metabolic pathways and genes related to defenses were changed in Arabidopsis after treated with FBT. Seneral differentially expressed genes were analyezed by Real-time PCR, and the result accords with the transcriptome database, proving the truth and reliability of the transcriptome database.In conclusion, the present study shows that FBT have an outstanding ability to induce resistance in the Chinese cabbage. Gene expression and transcriptome analysis showed that large number of functional genes related to JA signaling pathway were involved in the induced resistance, JA pathway was shown to play a important role in the systemic resistance induced by FBT.