| Rice stripe disease,caused by rice stripe virus which transmitted by small brown planthopper(Laodelphax striatellus),results in serious yield losses to rice during last decades.In this study,RNA-Seq was used to analyze the transcriptomic difference between the resistant and susceptible varieties of rice at different times after RSV infection.For high resistance variety(Zhendao 88),1748up-regulated and 829 down-regulated differentially expressed genes(DEGs)were identified at 2 days post inoculation(dpi);1694 up-regulated and 1148 down-regulated genes at 10 dpi;831 up-regulated and 742 down-regulated at 20 dpi.For high susceptibility variety(Wuyujing 3),1810 and 1445 genes were up-regulated and down-regulated at 2 dpi;1497 up-regulated and 1697 down-regulated DEGs at10 dpi;2523 up-regulated and 1981 down-regulated at 20 dpi,respectively.After KEGG annotation of the unique DEGs of the two varieties,the metabolic pathways are quite different,indicating that the effect of RSV on the two varieties are different.For the susceptible variety,specific metabolic pathways include ascorbic acid and aldonic acid metabolism,porphyrin and chlorophyll metabolism,endocytosis,etc;specific metabolic pathways of resistant variety include zeatin biosynthesis,fatty acid degradation,MAPK(mitogen-activated protein kinase)signaling pathway,etc.In addition,resistant and susceptible varieties have great differences in the pathway of plant-pathogen interaction.There were more DEGs involved in this pathway in the resistant variety than in the susceptible variety,which were significantly up-regulated,for example,Os07g0129300 was overexpressed 4.08 times in resistant variety and down-regulated 1.95 times in susceptible variety.The DEGs related to photosynthesis,chlorophyll biosynthesis,carbon metabolism,amino acid biosynthesis and ribosome biosynthesis were both down-regulated for these two varieties.Furthermore,through Gene Ontology(GO)annotation,the DEGs related to transcription factors,peroxidases,and kinases of two varieties at three time points were identified.The results showed that the number of DEGs of the resistant variety was less than that of susceptible,but after significant analysis,the expression levels were significantly up-regulated or down-regulated under the condition of | log2(FoldChange)|> 0 and padj <0.05.Then through KEGG annotation,the DEGs associated with plant hormone signal transduction,plant-pathogen interaction,and autophagy,which have contribution to plant disease resistance,were analyzed.The results showed that the pathway of hormone signal transduction,the resistance response mediated by the negative regulation of abscisic acid(ABA)and regulation of brassinosteroids(BR)were similar in two varieties,but the resistance reaction mediated by salicylic acid(SA)and jasmonic acid(JA)/ ethylene(ET)were different.For plant-pathogen interaction,the DEGs of the two varieties in three periods involved in both PTI(PAMP-triggered immune)and ETI(effector-triggered immune),but the unique DEGs of susceptible variety only involved in PTI,the unique genes of resistant variety only associated with ETI.Only up-regulated DEGs of the susceptible variety were found to involve in autophagy pathway.These results revealed the difference between resistant and susceptible varieties in the transcription level after RSV infection.Wheat dwarf virus(WDV),a mastrevirus transmitted by the leafhopper(Psammotettix alienus),causes a severe disease in cereal crops.Typical symptoms of wheat plants infected by WDV are increased tillering and severe dwarfing.In this present study,RNA-Seq was used to perform gene expression analysis in wheat plants in response to WDV infection.Comparative transcriptome analysis indicated that a total of 1042 DEGs were identified in the comparison between mock and WDV-inoculated wheat plants.GO assignment was performed to classify the gene function of unigenes.Both up-regulated and down-regulated DEGs can be categorized into three main categories: biological process,cellular component,and molecular function.GO annotation revealed 707 DEGs associated with different biological processes,such as phytohormone metabolism,photosynthesis,DNA metabolic process,response to biotic stimulus and defense response.To further understand the biological processes in which these DEGs are involved,KEGG database was used to analyze the pathway annotation of unigenes.KEGG pathway analysis noted that 726 differentially expressed genes participate in different pathway responses,including carbon fixation,TCA cycle,and plant hormone signaling.Among these,DEGs involved in phytohormone and photosynthesis metabolism and response pathways were further enriched and analyzed,which indicated that hormone biosynthesis,signaling and chloroplast photosynthesis-related genes might play an important role in symptom development after WDV infection.These results showed that the infection of WDV might affect the normal progress of photosynthesis and chlorophyll synthesis,suggesting that the WDV infection may have significant effect on signaling and biosynthesis of AUX,CKs,BRs and ET,and meanwhile contribute to symptom development through reduced expression of related gene excepting CKs pathway.Additionally,the ABA-mediated signaling pathway might negatively regulate the defense system during WDV infection.These results illustrate the dynamic nature of the wheat-WDV interaction at the transcriptome level and confirm that symptom development is a complex process,providing a solid foundation to elucidate the pathogenesis of WDV. |
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