Effects Of Fungicides On The Infection Of Rice Stripe Virus To Rice And The Transcriptome Analysis Of Rice And Rapeseed Leaves Treated By Salicylhydroxamic Acid

In recent years,rice stripe disease which is caused by Rice stripe virus（RSV）has been erupting in many rice growing areas in China.And it is especially harmful to japonica areas.Laodelphax striatellus Fallén（small brown planthopper,SBPH）is the main transmission medium of rice stripe virus.The migration and explosion of small brown planthopper directly affected the occurrence and prevalence of rice stripe disease.But the migration of small brown planthopper is affected by many environmental factors,which causes the prevention and treatment of the diseases to be extremely passive.The internal-absorbent fungicides are commonly used in the prevention and treatment of a variety of fungal diseases in rice,which can be absorbed by rice and passed to the whole plant.It is speculated that the small brown planthopper migrate to rice that has been used with internal-absorbent fungicides may have an impact on itself and the occurrence of the disease.In this study,five kinds of internal-absorbent fungicides（carbendazim,tricyclazole,azoxystrobin,propiconazole,and thifluzamide）,which are commonly used in rice,were pretreated with 2 to 3 leaves of rice seedlings,and then inoculated with different small brown planthoppers with and without virus.Among them,the tricyclazole-treated rice had more extensive effects on the intake avoidance,adult oviposition avoidance and lethal rate of various types of the small brown planthopper than other fungicides.However,these kinds of fungicides only have effects on the small brown planthopper at high concentrations,which are much higher than the concentrations used in the field.This indicates that the use of these internal-absorbent fungicides at field concentrations may have minimal impact on the feeding,spawning and other behaviors of the transmitted small brown planthopper.The content of RSV and the virus infection rate in rice is increased with the feeding time of the small brown planthopper.Five kinds of fungicides were used to detect the RSV infection rate in rice by RT-PCR at the concentration commonly used in the field for 6 days after feeding with the small brown planthopper.All fungicides were found to promote virus infection and proliferation in rice relative to their respective solvent controls.Because these kinds of fungicides had little effect on the small brown planthopper at field concentration,the use of these fungicides promoted the infection RSV to rice,which increased the disease incidence of rice.Inhibitory effect of fungicides on the expression of certain disease-resistant genes in rice may be one of the reasons that the RSV infection rate increased.Salicylhydroxamic acid（SHAM）inhibits the resistance of plants to viruses.An antiviral response exists independent of the PR protein synthesis pathway,SHAM-sensitive pathway.Transcriptome sequencing was used to study the differential gene expression of SHAM treated rice and rapeseed leaves.The majority of genes with significant differences in expression were found to be related to the plant resistance pathway.By analyzing the up-regulated and down-regulated gene types in two plants,and the effects of SHAM on signal transduction pathways of salicylic acid,jasmonic acid and ethylene,the understanding of SHAM regulation of plant resistance was enhanced.It may promote viral resistance research.In order to find an artificial inoculation method that makes RSV infest rice without relying on the small brown planthopper.We obtained the micro-wounding of rice by artificial methods.The viruses derived from grinded fluid of the virus-carried small brown planthopper,RSV infected rice,or the purified RSV from rice were combined with different p H buffering system（acetic acid-sodium acetate buffer,p H 4.0;MES-KOH,p H5.7;phosphate-citrate buffer,p H 5.0;phosphate buffer p H 7.5 and p H6.0）and different solutes（polyethylene glycol 6000,polyethylene glycol 4000,Ca Cl₂,mannitol,SHAM）.To explore the direct infection methods of rice by RSV,we used these solutions to impregnate the rice wounds,change the lighting conditions and other methods to treat rice.However,RSV were not successfully detected in all the treated rice seedlings by RT-PCR.