【作者】 李科；

【导师】 青玲；

【作者基本信息】 西南大学 ， 植物病理学， 2018， 博士

【摘要】 烟草曲茎病毒（Tobacco curly shoot virus,TbCSV）是属于Geminiviridae科Begomovirus属的单组分病毒,伴随β卫星（Tobacco curly shoot betasatellite,TbCSB）,在我国云南和四川省广泛发生且危害严重,是引起番茄和烟草曲叶病的重要病原。我国单组份双生病毒与β卫星的进化关系及互作机制复杂,TbCSV被认为在进化中介于需要卫星的双生病毒和真正的单组分双生病毒之间,因此,开展对该病毒及其伴随卫星的研究对于解读双生病毒的起源和遗传进化机制具有重要意义。目前对TbCSV及TbCSB已开展的研究工作主要集中在病毒检测、致病性、基因功能、蛋白定位、种群变异分析、基因沉默载体构建等方面,该病毒在寄主植物体内与寄主互作的方式和作用细节,对寄主内源基因表达的影响,对寄主生物过程的影响,以及寄主植株对抵抗病毒入侵的响应这些问题尚不明确,弄清这些问题将有助于全面解析该病毒的致病机理。本论文拟利用转录组测序及生物信息学分析方法,分析TbCSV侵染对本氏烟内源基因表达的影响,以及这些差异表达基因的功能、作用方式和参与的生物途径。基于生物信息学分析结果,借助基因沉默及过表达技术,分析TbCSV及TbCSB侵染对本氏烟光合作用相关途径的影响,并明确本氏烟PR和LRR-RLK基因对TbCSV及TbCSB侵染的响应及本氏烟BR和JA途径对TbCSV及TbCSB侵染的响应。本论文的主要研究结果如下:1.病毒侵染对本氏烟内源基因表达的影响利用转录组测序技术,从TbCSV单独侵染（TbCSV或Y35A）以及TbCSV与TbCSB共侵染（TbCSV+TbCSB或Y35AB）的本氏烟中共鉴定出59814条基因,其中,3196条基因在Y35A vs CK中差异表达,占基因总数的5.3%,其中1391条上调表达,1805条下调表达;有4081条基因在Y35AB vs CK中差异表达,占基因总数的6.8%,其中1775条上调表达,2306条下调表达。在Y35AB vs CK中的差异表达基因（Differential expression genes,DEGs）共富集3074个GO term,上调基因和下调基因分别富集2215和2658个GO term,其中显著富集GO term 124个,上调表达和下调表达的基因各85和166个。Y35A vs CK中的DEGs共富集2966个GO term,上调基因和下调基因分别富集2041和2033个GO term,其中显著性富集GO term 76个,上调表达和下调表达的基因各78和66个。这些DEGs主要与生物过程、代谢过程、细胞过程、有机物代谢过程、初级代谢过程等功能相关,参与核糖体、植物激素信号转导、代谢途径、DNA复制、暗反应中的固碳作用等过程。随机筛选了12条基因用RT-qPCR进行验证,12条基因表达量的变化趋势与测序结果一致。进一步分析发现,TbCSV或TbCSV+TbCSB侵染后本氏烟光合作用相关及防御相关基因的表达均受到影响,为进一步明确因此进行了以下研究。2.病毒侵染对本氏烟光合作用的影响为明确病毒侵染对寄主光合作用的影响,在TbCSV或TbCSV+TbCSB侵染20d,提取并测定本氏烟叶绿素含量,并对其光合生理特性进行了测定。结果表明,对照植株叶绿素a的含量为579.7μg/g,TbCSV单独侵染和TbCSV+TbCSB共侵染植株叶绿素a的含量分别为458.7μg/g和475.0μg/g,显著低于对照植株。对照植株叶绿素b的含量为141.6μg/g,TbCSV单独侵染和TbCSV+TbCSB共侵染植株叶绿素b的含量分别为122.3μg/g和126.7μg/g,与对照植株相比有所下降,但差异不显著。本氏烟光合生理特性测定结果显示,与对照植株相比TbCSV或TbCSV+TbCSB侵染后本氏烟净光合速率（Pn）、气孔导度（Gs）、蒸腾速率（Tr）、气孔限制值（LS）、水分利用效率（WUE）、光能利用效率（LUE）和CO₂利用效率（CUE）显著降低,而胞间CO₂浓度（Ci）显著上升。叶绿素荧光特性测定结果显示,与对照植株相比TbCSV或TbCSV+TbCSB侵染后植株非光化学淬灭系数（qN）和激发能捕获效率（Fv’/Fm’）上升,电子传递速率（ETR）、光化学量子产量（ΦPSII）和光化学淬灭系数（qP）下降。叶绿体超微结构观察结果显示,TbCSV或TbCSV+TbCSB侵染后导致本氏烟叶绿体数量减少,TbCSV单独侵染植株叶绿体中有中等尺寸的淀粉粒积累,TbCSV+TbCSB共侵染接种植株叶绿体形态肿胀,弯曲变形,内部的片层结构因膨压被挤到一边。从测序数据中筛选了23条同时在TbCSV和TbCSV+TbCSB侵染后表达丰度较高且差异倍数较大的DEGs,其中15条基因与叶绿体相关,占筛选基因的65%。利用TRV或PVX介导23条目标基因在本氏烟中表达,结果显示NbGDCSa、NbGDCSb、NbrbcS、NbChlHa、NbChlHb、NbDXS、NbHemA、NbBchP、NbGRP和NbPU被介导表达后,本氏烟表型发生变化,主要表现为叶片的黄化、白化、褪绿、斑驳、脉明、萎蔫坏死、卷曲、突起及植株矮化等。这些结果表明,TbCSV或TbCSV+TbCSB的侵染降低了本氏烟光合作用的能力。3.本氏烟PR和LRR-RLK基因对病毒侵染的响应为了明确本氏烟PR和LRR-RLK基因对病毒侵染的响应,在前期分析显示差异表达的基因中随机筛选了11条PR基因和12条LRR-RLK基因,利用RT-qPCR检测其在TbCSV或TbCSV+TbCSB侵染4 dpi、8 dpi和12 dpi时的表达量。结果显示,NbPR2、NbPR3、NbPR11（PR基因）和Nb1g56140、Nb1g67720、Nb2g16250、NbEI-LRR（LRR-RLK基因）在TbCSV或TbCSV+TbCSB侵染后的3个时间点的表达量均上调;NbPR1、NbPR4、NbPR5、NbPR9、NbPR10a、NbPR17（PR基因）和Nb1g06840、Nb3g47570a、Nb4g26540、Nb4g30520、NbGSO1（LRR-RLK基因）在TbCSV或TbCSV+TbCSB侵染后的部分时间点表达量上调,而其余时间点与对照相比差异不显著;NbPR6、NbPR10b（PR基因）和Nb3g47570b、Nb4g36180、NbFbLRR-MAX2（LRR-RLK基因）在TbCSV或TbCSV+TbCSB侵染后有的时间点上调表达,有的时间点下调表达。随机选择NbPR2、NbPR6、NbPR9、NbPR10a和NbPR11,利用TRV分别介导在本氏烟中表达,检测TbCSV或TbCSV+TbCSB侵染4 dpi、8 dpi和12 dpi时TbCSV及TbCSB的积累量。结果显示,NbPR2、NbPR6、NbPR9、NbPR10a沉默后,在TbCSV或TbCSV+TbCSB侵染4 dpi时TbCSV的积累量均显著增加,此时TbCSB的积累量在NbPR9和NbPR10a的沉默植株中也显著增加。而NbPR11沉默后,在TbCSV或TbCSV+TbCSB侵染4 dpi和8 dpi时TbCSV的积累量均显著降低,4 dpi时TbCSB的积累量也显著降低。这些结果表明,本氏烟PR和LRR-RLK基因对TbCSV或TbCSV+TbCSB的侵染作出响应,部分PR基因对TbCSV及TbCSB的积累量具有一定的调控作用。4.本氏烟BR和JA途径对病毒侵染的响应为了明确BR和JA途径对病毒侵染的响应,筛选了6条BR途径相关基因和10条JA途径相关基因,用RT-qPCR检测其在TbCSV或TbCSV+TbCSB侵染4 dpi、8 dpi和12 dpi时的表达量。结果显示,NbBZR1、NbCYCD3-X2（BR途径）和NbDOX1、NbHPL1、NbKAT2、NbJAR1、NbJAZ1、NbJAZ2（JA途径）在TbCSV或TbCSV+TbCSB侵染后的部分时间点表达量上调,而其余时间点与对照相比差异不显著;NbCYP90C1/D1、NbBRI1、NbBZR2、NbCYCD3-X1（BR途径）和NbSAMT1、NbSAMT2、NbCOI1、NbMYC2（JA途径）在TbCSV或TbCSV+TbCSB侵染后有的时间点上调表达,有的时间点下调表达。本氏烟JA含量检测结果显示,TbCSV或TbCSV+TbCSB侵染12 dpi对照植株JA的含量为8.89 pg/g,TbCSV单独侵染植株为14.04 pg/g,TbCSV+TbCSB共侵染植株为12.33 pg/g,TbCSV或TbCSV+TbCSB侵染后JA的含量上升,但未达到显著水平。因BZR1和CYCD3基因参与调控植物的生长发育,为明确本氏烟NbBZR1和NbCYCD3-X1在生长发育和抗病防御中的作用,以PVX介导本氏烟NbBZR1和NbCYCD3-X1的表达,结果显示,NbBZR1过量表达20 d时本氏烟与对照植株相比株高明显变矮,节间距变短,顶部叶片出现向下皱缩、变形,上部部分叶片出现均匀分布的白色坏死斑。NbCYCD3-X1过量表达20 d时植株与对照相比可观察到新叶呈轻微皱缩。目标基因沉默或过表达后,TbCSV及TbCSB的积累量检测结果显示,无论NbBZR1沉默或过表达后,在TbCSV或TbCSV+TbCSB侵染4 dpi时TbCSV及TbCSB的积累量均显著降低。NbCYCD3-X1过表达后,在TbCSV或TbCSV+TbCSB侵染4 dpi时TbCSV的积累量显著降低,但TbCSB的积累量显著上升。JA途径受体基因NbCOI1沉默后,TbCSV的积累量在TbCSV单侵染8 dpi和12 dpi时显著降低,但在TbCSV+TbCSB共侵染3个时间点均显著上升,而TbCSB的积累量在4 dpi时显著降低。外源性MeJA和BL处理后,TbCSV及TbCSB的含量变化趋势在两种处理方法中一致,在TbCSV单独侵染4 dpi时TbCSV的含量显著上升,8 dpi和12 dpi时显著下降;而在TbCSV+TbCSB共侵染4 dpi和8 dpi时TbCSV及TbCSB的含量显著下降,12 dpi时TbCSV及TbCSB的含量显著上升。这些结果表明,本氏烟BR和JA途径参与了寄主抗TbCSV及其伴随卫星的侵染。5.BR和JA途径在响应病毒侵染过程中发生相互作用研究发现,BL处理本氏烟12 h后JA途径基因NbCOI1的表达量显著上升,在TbCSV单独侵染3个时间点的表达量均上升,在TbCSV+TbCSB共侵染4 dpi和12 dpi时也上升。MeJA处理6 h和12 h后NbBRI1的表达量均显著上升,在TbCSV单独侵染4 dpi和8 dpi时表达量上升,在TbCSV+TbCSB共侵染4 dpi和12 dpi时的表达量也上升。MeJA+BL共同处理后12 h NbCOI1和NbBRI1的表达量均显著上升,在TbCSV单独侵染的3个时间点,NbCOI1和NbBRI1的表达量均上升,在TbCSV+TbCSB共侵染4 dpi时,NbCOI1和NbBRI1的表达量也均上升。以上结果表明,MeJA处理后在TbCSV或TbCSV+TbCSB侵染前后,BR途径受体基因NbBRI1被诱导上调表达。同样,BL处理后在TbCSV或TbCSV+TbCSB侵染前后,JA途径受体基因NbCOI1也被诱导上调表达。同时,MeJA+BL共同处理后NbBRI1和NbCOI1均有被诱导上调表达。由此推测,MeJA和BL处理相互促进了彼此信号通路中受体基因的表达量上调,表明BR和JA途径在参与本氏烟对TbCSV或TbCSV+TbCSB侵染的调控过程中存在相互促进作用。本研究中,转录组分析表明TbCSV或TbCSV+TbCSB侵染后本氏烟内源基因的表达受到不同程度的影响,涉及本氏烟各项生理功能和生物过程。研究结果表明,TbCSV或TbCSV+TbCSB侵染后本氏烟光合作用能力降低。同时,本氏烟PR和LRR-RLK基因,以及BR和JA途径参与了本氏烟抗TbCSV及其伴随卫星的侵染,并参与调控病毒及卫星的积累量。这些研究结果可为解析TbCSV及其伴随卫星与寄主相互作用的分子机制,以及寄主抗病机制提供科学依据。更多还原

【Abstract】 Tobacco curly shoot virus（TbCSV）is a monopartite virus belonging to the genus Begomovirus in the family Geminiviridae.TbCSV is an important pathogen causing leaf curl disease on tomato and tobacco,widely spreaded and have caused great losses to crops in Yunnan and Sichuan province.The evolutionary relationship and interaction mechanism between monopartite begomovirus and betasatellite is complicated in China.TbCSV is considered to be an evolutionary intermediate between the betasatellite requiring begomoviruses and the truly monopartite begomoviruses.Therefore,the study of TbCSV is of great significance for elucidating the origin and genetic evolution mechanism of geminivirus.At present,some studies has been carried out on TbCSV and TbCSB,mainly focusing on virus detection,pathogenicity,gene function,protein localization,population variation analysis,gene silencing vector construction.However,interaction mechanism of TbCSV with host,influence on host gene expression and biological processes and TbCSV-triggered disease resistance are still unclear.Making clear of above questions will help to resolve the pathogenesis of the TbCSV.In this study,the TbCSVon the endogenous gene the impacts of TbCSV infection on the endogenous genes expression of N.benthamiana,the functional roles and involved biological processes of these differential expression genes（DEGs）were analysed by transcriptome sequencing technology.Based on bioinformatics results,changes in photosynthesis pathway,responses of PR and LRR-RLK genes and BR and JA pathways involvement post TbCSV+TbCSB infection were explicated by gene silencing and overexpression,and research results of this study are summarized as follows:1.Effects of TbCSV and TbCSV+TbCSB infection on the endogenous genes expression of N.benthamianaThrough transcriptome sequencing,59814 genes were identified from both TbCSV-infected and TbCSV+TbCSB-infected plants.Among them,3196 differentially expressed genes（DEGs）were identified in group Y35A vs CK,5.3%of the total number of genes.Among them,1391 genes were up-regulated and 1,805 genes were down-regulated.4081 DEGs were identified in group Y35AB vs CK,6.8%of the total number of genes.Among them,1775 genes were up-regulated and 2306 genes were down-regulated.The DEGs in group Y35AB vs CK were enriched in total of 3074 GO terms with 2215 GO terms from up-regulated genes and 2658 GO terms from down-regulated genes,respectively.124 GO terms were significantly enriched,85 GO terms from up-regulated DEGs and 166 GO terms from down-regulated DEGs.The DEGs in group Y35A vs CK were enriched in total of 2,966 GO terms,among them the up-regulated and down-regulated DEGs enriched 2041 and 2033 GO terms,respectively.76 GO terms were significantly enriched,78 GO terms from up-regulated DEGs and 66GO terms from down-regulated DEGs.These DEGs mainly involved in biological process,metabolic process,cellular process,organic substance metabolic process,primary metabolic process,and play roles in biological pathways including ribosome,plant hormone signal transduction,metabolic pathways,DNA replication,carbon fixation in photosynthetic organisms.12 genes were randomly selected for RT-qPCR,and the expression trends of these genes were consistant with sequencing data.Upon TbCSV and TbCSV+TbCSB infection,the expression levels of defense-related genes and genes involved in photosynthesis were altered.How these genes function during virus infection needs further investigation.2 Effects of TbCSV infection on the photosynthesisAt 20 dpi,the contents of chlorophyll a in TbCSV-infected and TbCSV+TbCSB-infected plants was 458.7μg/g and 475.0μg/g,respectively,of which significantly lower than that in control plants（579.7μg/g）.Compared to control plants（141.6μg/g）,the content of chlorophyll b in TbCSV-and TbCSV+TbCSB-infected plants were 122.3μg/g and 126.7μg/g,respectively,of which were decreased without significant differences.The determination of photosynthetic physiological characteristic in N.benthamiana plants after TbCSV-and TbCSV+TbCSB-infected showed that the Net photosynthetic rate（Pn）,Stomatal conductance（Gs）,Transpiration rate（Tr）,Value of stomatal limits（LS）,Water use efficiency（WUE）,Light use efficiency（LUE）and CO₂use efficiency（CUE）of TbCSV-or TbCSV+TbCSB-infected plants were significantly reduced when compared to control plants,while Intercellular carbon dioxide concentration（Ci）was significantly increased.The results of chlorophyll fluorescence characteristics measurement showed that the Non-photochemical quenching（qN）and Excitation capture efficiency of PSП（F_v’/F_m’）in TbCSV-or TbCSV+TbCSB-infected plants were increased,Electron transport rate（ETR）,Quantum efficiency of PSП（ΦPSII）and Photochemical quenching（qP）were reduced when compared to control plants.Ultrastructural observation of chloroplast revealed decreased number of chloroplast in both TbCSV-infected and TbCSV+TbCSB-infected plants.Medium-sized starch granules were accumulated in the chloroplast in TbCSV-infected plants.Swelling chloroplast,bending deformation,and squeezed lamellar structure inside the chloroplast were observed in TbCSV+TbCSB-infected plants.Among tweenty-three DGEs that induced upon both TbCSV and TbCSV+TbCSB infection,15 genes（65%）were related to chloroplast.After TRV-or PVX-mediated expression of candidate genes NbGDCSa,NbGDCSb,NbrbcS,NbChlHa,NbChlHb,NbDXS,NbHemA,NbBchP,NbGRP and NbPU in N.benthamiana,plants exhibiting yellowing,albino,chlorisis,mottle,vein clearing,wilting and necrosis,leaf curling,bulging and dwarfing.These results verified that infection with TbCSV or TbCSV+TbCSB could reduce the photosynthesis of plants.3 Responses of PR and LRR-RLK genes upon TbCSV infectionTo clarify the involvement of PR and LRR-RLK genes during virus infection,11diffrentially expressed PR genes and 12 diffrentially expressed LRR-RLK genes were randomly selected for quantification at 4,8 and 12 dpi in TbCSV-infected and TbCSV+TbCSB-infected plants.RT-qPCR results showed that the expression levels of genes NbPR2,NbPR3,NbPR11（PR genes）and Nb1g56140,Nb1g67720,Nb2g16250,NbEI-LRR（LRR-RLK genes）all were up-regulated at 4 dpi,8 dpi and 12 dpi in both TbCSV-infected and TbCSV+TbCSB-infected plants.The expression levels of NbPR1,NbPR4,NbPR5,NbPR9,NbPR10a,NbPR17（PR genes）and Nb1g06840,Nb3g47570a,Nb4g26540,Nb4g30520,NbGSO1（LRR-RLK genes）were up-regulated at some time points and not significantly expressed at other time points in TbCSV-infected or TbCSV+TbCSB-infected plants.The expression levels of NbPR6,NbPR10b（PR genes）and Nb3g47570b,Nb4g36180,NbFbLRR-MAX2（LRR-RLK genes）were up-regulated at some time points after TbCSV-or TbCSV+TbCSB-infection and down-regulated at other time points.Post TRV-mediated expression of NbPR2,NbPR6,NbPR9,NbPR10a and NbPR11,plants were agro-infiltrated with TbCSV or TbCSV+TbCSB and the accumulation of TbCSV and TbCSB were detected at 4 dpi,8 dpi and 12 dpi.The results showed that after silencing of NbPR2,NbPR6,NbPR9 and NbPR10a,the accumulation of TbCSV was significantly increased at 4 dpi in TbCSV-infeted and TbCSV+TbCSB-infected plants,respectively.The accumulation of TbCSB was significantly increased in both NbPR9-silenced and NbPR10a-silenced plants.While in NbPR11-silenced plants,the accumulation of TbCSV was significantly decreased at 4dpi and 8 dpi in both TbCSV-infected and TbCSV+TbCSB-infected plants,and the accumulation of TbCSB also was significantly decreased at 4 dpi.These results uncovered that PR and LRR-RLK genes response to TbCSV or TbCSV+TbCSB infection and partial PR genes regulate the accumulation of TbCSV and TbCSB during infection.4 Responses of BR and JA pathway-related genes to TbCSV infectionTo identify the potential roles of BR and JA pathway in virus infection,6 BR pathway-related genes and 10 JA pathway-related genes were screened and quantified by RT-qPCR in TbCSV-or TbCSV+TbCSB-infected plants at 4,8 and 12 dpi.The expression levels of NbBZR1,NbCYCD3-X2（BR pathway）and NbDOX1,NbHPL1,NbKAT2,NbJAR1,NbJAZ1、NbJAZ2（JA pathway）were up-regulated upon TbCSV-or TbCSV+TbCSB infection at some time points and not significantly expressed at other time points compared to the control.The expression levels of NbCYP90C1/D1,NbBRI1,NbBZR2,NbCYCD3-X1（BR pathway）and NbSAMT1,NbSAMT2,NbCOI1,NbMYC2（JA pathway）were up-regulated at some time points after TbCSV or TbCSV+TbCSB infection,and down-regulated at some time points.The JA content detection results showed that upon TbCSV or TbCSV+TbCSB infection at 12 dpi,the JA contents in plants infected by TbCSV（14.04 pg/g）or TbCSV+TbCSB（12.33 pg/g）were increased when compared with control（8.89 pg/g）.Because BZR1 and CYCD3 are involved in the regulation of plant growth and development,and to clarify the potential roles of NbBZR1 and NbCYCD3-X1 in development and defense,they were overexpressed by PVX and results exhibited that 20 days after NbBZR1 overexpression,shorter plant height and pitch,downward crinkle,deformation and uniform distribution of necrotic spots were observed in overexpressed plants.NbCYCD3-X1 overexpressed plants showed slightly crinkle in the newly emerged leaves compared to control plants.After silencing or overexpression of the candidate genes,the accumulation of TbCSV and TbCSB were detected.No matter NbBZR1 was silenced or overexpressed,the accumulation of TbCSV and TbCSB were significantly decreased at 4 dpi in both treatments compared to control.After overexpression of NbCYCD3-X1,the accumulation of TbCSV was significantly decreased at 4 dpi in both treatments compared to control,but the accumulation of TbCSB was significantly increased at 4dpi.After silencing of NbCOI1,the accumulation of TbCSV was significantly decreased at 8 and 12 dpi in TbCSV-infected plants,but significantly increased at 4,8 and 12 dpi in TbCSV+TbCSB-infected plants,while the accumulation of TbCSB was significantly decreased at 4 dpi.After treatment with exogenous MeJA and BL,the accumulation trend of TbCSV and TbCSB was consistent in the two treatments.The accumulation of TbCSV was significantly increased at 4 dpi in TbCSV-infected plants,and was significantly decreased at 8 and 12 dpi.While the accumulation of TbCSV and TbCSB were significantly decreased at 4 dpi and 8 dpi,and was significantly increased at 12 dpi in TbCSV+TbCSB-infected plants.5 Interaction between BR and JA pathways in response to virus infectionTwelve hours post BL treatment,the expression level of NbCOI1 was significantly increased.The expression levels of NbCOI1 was increased at all three time points post TbCSV infection,and was increased at 4 dpi and 12 dpi in TbCSV+TbCSB-infected plants.Six and twelve hours after treatment with MeJA,the expression level of NbBRI1was significantly increased.The expression level of NbBRI1 was increased at 4 dpi and8 dpi in TbCSV-infected plants,and was increased at 4 dpi and 12 dpi in TbCSV+TbCSB-infected plants.After co-treatment with MeJA+BL 12 h,the expression level of NbCOI1 and NbBRI1 were significantly increased.The expression levels of NbCOI1 and NbBRI1 were both increased in TbCSV-infected plants at three time points,and were increased in TbCSV+TbCSB-infected plants at 4 dpi.The above results indicated that after treatment with MeJA,the BR pathway receptor gene NbBRI1was induced before or after infection with TbCSV or TbCSV+TbCSB.Similarly,after treatment with BL,the JA pathway receptor gene NbCOI1 was also induced before or after infection with TbCSV or TbCSV+TbCSB.Moreover,after co-treatment with MeJA+BL,the NbBRI1 and NbCOI1 were induced.It was speculated that the MeJA and BL treatments promoted the expression of these two the receptor genes in both signaling pathways.This indicated that mutual promotion between BR pathway and JA pathway plays a role in the regulation process of plant resistance to TbCSV or TbCSV+TbCSB infection.In this study,transcriptome analysis indicated that TbCSV or TbCSV+TbCSB infection affect the expression of host genes that involved in various physiological functions and biological processes.Upon TbCSV or TbCSV+TbCSB infection,the photosynthesis ability of host plants was reduced.At the same time,PR and LRR-RLK genes,as well as the BR and JA pathways,participate in defense to the infection of TbCSV and its betasatellite,and are involved in the regulation of viral and satellite accumulation.These findings provide a scientific basis for the molecular mechanisms between virus/betasatellite-host interactions,as well as host disease resistance mechanisms.更多还原