The Effect Of Antibiotic Treatment On The Bacterial Symbionts Of Brown Planthopper And Its Correlation With Rice Virulence

Rice is an important food crop in China,and the planting area is very extensive.The abundance of rice has a major impact on China’s food security.The complexity of the rice pests brown planthopper(BPH)and white-backed planthoppers(WBPH)makes to overcome rice resistance and bring great difficulties to prevention and control.The long-term control methods relying on pesticides and pesticides not only have limited results,but also cause environmental pollution.BPH and WBPH feed on rice phloem sap by sucking mouthparts,affecting rice growth and yield,and also spread a variety of rice viruses.It is the primary pest in rice production in China.The bacterial symbionts of insects have multiple functions,and their presence affects various physiological functions of the host.There is already evidence that bacterial symbionts are important factors influencing the formation and selection of host plants of Homoptera insects.This study focused on the bacterial symbionts of BPH and the WBPH,and achieved the following results:(1)High-throughput sequencing and bioinformatics analysis of the transcriptome of the antibiotic rifampicin-treated BPH(biotype 1)and untreated BPH(biotype 1),and the transcriptome sequencing results were analyzed.A total of 87,628 Unigenes were obtained by splicing.Unigenes commented and analyzed.The results showed that among the annotated 2919 differentially expressed genes,most of the differentially expressed Unigenes(97%of the total)showed up-regulation,and only 3%of the differentially expressed Unigenes showed down-regulation;(2)The untreated BPH and the BPH,which were treated with the antibiotic rifampicin,were fed on rice,and the rice transcriptome was subjected to high-throughput sequencing and bioinformatics analysis.Through the pairwise comparison analysis,3727,3441 and 774 differentially expressed genes(DEGs)were annotated,respectively.Only 113 of the three groups of DEGs appeared simultaneously.It indicated that most of the DEGs were caused by rice feeding on rice,while the difference in gene expression caused by untreated BPH and antibiotic rifampicin-treated BPH was not obvious.According to the results of bioinformatics analysis,candidate genes related to rice-microorganism,rice defense response and signal transduction pathway were selected,and qPCR verification analysis was carried out;(3)High-throughput sequencing and bioinformatics analysis of the abundance and diversity of bacterial symbionts of different biotypes BPH populations(biotype 1,biotype 2 and biotype 3)and different antibiotic-treated BPH populations(ampicillin,kanamycin and rifampicin).The population was analyzed for data and classified into 152 OTUs.There were 77 OTUs detected in all three biotypes,accounting for 50.7%of all OTUs,indicating that half of the OTUs were unique to each biotype;110 OTUs were detected under four treatments,accounting for 110 72.4%of all OTUs.Annotation and relative abundance analysis of OTUs revealed that there were large differences in bacterial symbionts in the three biotypes BPH,and each of the biotypes had a special relatively abundant bacterial symbiont.Biotype 1 is mainly of the genus Wolbachia and Cardinium;In biotype 2,it is mainly of the genus Arsenophnus,Stenotrophomonas and Enterobacter.Biotye 3 is mainly of the genus Arsenophnus and Aeromonas.After treatment with different antibiotics,the species and abundance of bacterial symbionts of BPH have also changed greatly.The relative abundance of Arsenophnus has an increasing trend,while the relative abundance of Cardinium has a decreasing trend.(4)By establishing 16S ribosomal DNA(16S rDNA)library and performing ARDRA analysis,the bacterial symbionts species of BPH and WBPH in Guizhou Province were identified.Twelve operational classification units(OTUs)were found in BPH field population in the field,and five OTUs were found in WBPH field population;(5)By optimizing the BOX-PCR amplification conditions of the bacterial symbionts of BPH and WBPH,a clear amplification band pattern was obtained,and the amplification results indicated that big different in the BOX-PCR amplification band type of the BPH and WBPH;(6)Bacterial symbionts of BPH bodys and they secreted into the rice leaf sheath were cultured.Three kinds of bacteria were detected in the bacterial symbionts culture of BPH,namely:Staphylococcus sciuri,Microbacterium kitamiense and Herbaspirillum seropedicae(rice nitrogen-fixing bacteria);two pantoea bacteria(Pantoea agglomerans)were detected in the culture of BPH feeding and secreting into rice sheath;...