Study On The Control Effect Of Buckwheat Root Exudates On Cabbage Clubroot Disease And Its Mechanism Of Prevention

Cabbage(Brassica oleracea L.var.capitata L.)which is a Cruciferous Brassica crops,is one of the most important vegetable crops in China.Clubroot is a worldwide soil-borne disease caused by Plasmodiophora brassicae Woron.,and mainly harms cruciferous crops.In recent years,this disease developed very quickly.And led a serious threat to the safety of cruciferous crops production.Buckwheat(Polygonaceae Fagopyrum Mill.)is a dicotyledonous cereal crops,Preliminary investigation for clubroot incidence and field experiments showed that rotation with Buckwheat and Cabbage had a good prevention effect on clubroot in Fuling District of Chongqing,however,the specific inhibition mechanisms is unknown.In this study,buckwheat root exudates was irrigated to cabbage root which has been inoculated Plasmodiophora brassicae,and inhibition effect of buckwheat root exudates to clubroot was anlysized,and the mechanism of inhibition of buckwheat to clubroot was revealed by analyze the physicochemical properties of soil,enzymes of cabbage rhizosphere soil,the changes of genes related with pathogenesis and expression of growth effect gene.This will provide new ideas and methods for the control effect of cabbage clubroot in the future.The results are as follows:1.Prevention effect on cabbage clubroot disease of Buckwheat root exudates treatmentThe study showed that the treatment of irrigating buckwheat root exudates to cabbage which was inoculated Plasmodiophora brassicae had a lower clubroot incidence and disease index(80% and 40.83)than the treatment of irrigating nutrient solution(100% and 62.12).Moreover,the buckwheat root exudates can induce cabbage to acquire resistance,and index was 34.27%.This shows that buckwheat root exudates can alleviate the occurrence of cabbage root disease to a certain extent.On the other hand,the buckwheat root exudates can also increase single plant fresh weight,root length and fibrous root weight,and promote growing of cabbage.2.The effects on the physical and chemical properties and enzymes of soil of buckwheat root exudatesIn this study,comparing the treatment of buckwheat root exudates with nutrient solution which were irrigated to cabbage,available nitrogen in the cabbage rhizosphere soil decreased,and available boron increased,and acide phosphatase activity increased,and invertase activity increased,urease activity increased.Cabbage clubroot disease index had significantly negative correlation with acid phosphatase and phosphorus content in rhizosphere soil,and had significantly positive correlation with soil catalase activity.3.Effect on the genes expression in cabbage root of buckwheat root exudatesIn this study,after irrigating buckwheat root exudates to cabbage which was inoculated Plasmodiophora brassicae,PR1,PR3,PR4,PR5,LOX2,PDF1.2 gene related with pathogenesis expressed in advance,and the expression quantity was significantly higher than treatment of irrigating nutrient solution.Moreover,after irrigating buckwheat root exudates to cabbage which was inoculated Plasmodiophora brassicae,growth related genes(NIT2,CDKA;1)had a higher expression quantity in the early period of the disease,and a lower expression quantity in the late onset.This showed that buckwheat may prevent cabbage clubroot through SA/JA pathway.In other words,it promoted pathogenesis related genes to express in advance and growth related genes to express then promoted growing development of cabbage plants to increase resistance,and reduced the expression of growth related genes in the late onset to delay the formation of swollen root.In summary,irrigation of buckwheat root exudates can prevent clubroot by reducing nitrogen content,and increasing the effective boron content of cabbage to promote root development,and improving soil acid phosphatase,and increasing the fertility of soil urease and invertase activity to promote plant growth.Buckwheat root exudate can increase the resistance by inducing plant SA,and advancing the gene expression of JA pathway,and increasing the accumulation of m RNA gene,and promoting cabbage plant growth in the Early cabbage clubroot incidence,and improving disease resistance,and reducing the content of auxin and cytokinin in the late onset,and delaying the formation of swollen root.