| Tomato bacterial wilt is a serious soil borne disease in tomato production.Currently,research on the control of tomato bacterial wilt mainly focuses on biological control,supplemented by chemical,physical,and agricultural control.However,due to the characteristics of R.solanacearum,such as high harm,rapid mutation,high resistance,multiple transmission routes,and wide host range.Therefore,when bacterial wilt occurs,it often leads to a large-scale reduction in tomato production.Currently,there is no specific drug available,and there is an urgent need to develop environmentally friendly and effective new drugs to prevent and control it.In this study,hydrothermal synthesis was used to prepare carbon quantum dots.Taking R.solanacearum as the experimental object,the inhibition effects of different carbon dots on them were first analyzed,and the carbon dots with significant effects were selected.Subsequently,the effects of different concentrations of carbon dots and their modifiers on R.solanacearum were measured,and the specific effects and antibacterial mechanisms of carbon dots were described in detail through inhibition rate,growth curve,minimum inhibition concentration(MIC),minimum bactericidal concentration(MBC),electron microscopic observation,morphological differences,and metabolomics.The main research results are as follows:At the concentration of 20μg/ml,the inhibitory effects of about 30 kinds of carbon dots on R.solanacearum were determined,and two kinds of carbon dots with significant inhibitory effects,namely,CDs-castor leaves(CDs-BM)and CDs-Dicranopteris pedata leaves(CDsMQ),were screened out.2.Selecting 1,2,4,8,12,18,24,30μg/ml CDs-BM and CDs-MQ,the bacteriostatic test of R.solanacearum was carried out.The results showed that the antibacterial effect of CDsBM was better than that of CDs-MQ,with MIC of 20μg/ml and 25μg/ml,MBC of 50μg/ml and65μg/ml,respectively.The inhibition of two kinds of carbon spots on bacterial wilt has significant concentration effect.3.Chemical reagents such as diammonium dicyandiamide,tetraethylammonium chloride,thioglycolic acid,formamide,thiourea and polyethyleneimine were selected,and CDs-BM and CDs-MQ were functionalized and subjected to simple antibacterial experiments at different reaction temperatures and time,and two kinds of carbon point modifiers(CDs-BM thio and CDs-MQ thio)with remarkable antibacterial effects were obtained.The MIC and MBC of CDsBM thio and CDs-MQ thio were15μg/ml and 20μg/ml,35μg/ml and 40μg/ml,respectively.After the introduction of-SH,the inhibitory effect of two kinds of carbon sites on bacterial wilt increased significantly and had significant concentration effect.4.Based on the transmission electron microscope results of bacterial wilt CK,CDs-BM,and CDs-MQ,the results of significant damage to the cell membrane,significant thinning of the cell wall,rapid reduction of lipid droplets,confusion in the distribution of electron density,and chromatin aggregation were observed,and the metabolomics were measured and analyzed.The results showed that there were 12 significantly enriched pathways,accounting for 9.2% of the total pathway,including differential pathways such as sphingolipids metabolism,fatty acid biosynthesis,and amino acid biosynthesis.Subsequently,we roughly classified the metabolic substances contained in them into three categories: organic acids and derivatives,lipids and lipid-like molecules,and nucleosides,nucleotides,and analogues.We classified and analyzed the substances with significant differences in these three categories,and roughly classified them into 21 different categories,However,most of them are carboxylic acids and derivatives,fatty acyls,prenol lipids,steroids and steroid derivatives,pyrimidine nucleosides,and purine nucleotides.Subsequently,based on the relationship between lipid droplets and lipids,combined with relevant data,the following conclusions were drawn: the expression levels of acetyl coenzyme A and acetyl coenzyme A decreased significantly,leading to serious obstruction of energy related pathways.Triglyceride is an important lipid component in lipid droplets.When acetyl-Co A is deficient,the synthesis of triglyceride will be blocked.In addition,the membrane composition of multiple lipids was significantly downregulated,indicating that the membrane structure was damaged.In addition,bacterial wilt has been under a high stress environment and requires a large amount of energy to maintain its own life activities,so lipid drop reduction is obvious.Finally,based on the differential enrichment pathway,fatty acid biosynthesis,combined with the three pathways of fatty acid elongation,fatty acid degradation,and glycerol metabolism,we constructed a differential metabolic pathway diagram centering on the common substance hexadecanoic acid to further elaborate the changes of lipid droplets.5.Through plant experiments,it can be clearly seen that CDs-BM has significant control effects on tomato bacterial wilt.Subsequently,we calculated the disease index of tomato bacterial wilt based on relevant literature.The results indicate that the lowest rate in the 50μg/ml CDs-BM group was only 28.47%.The clear water group has the highest,reaching 81.94%.The median of the 100μg/ml CDs-BM group was 54.17%. |
PDF Full Text Request