Effects Of CMV On Fruit Quality Of Passion Fruit And Its Prevention And Control

Cucumber mosaic virus(CMV)is the main pathogen of Passiflora edulis virus disease,which has a serious impact on the planting,cultivation and fruit quality of Passiflora edulis,and has caused a great threat to the Passiflora edulis industry.There is no anti-CMV agent with high control effect on the market now,and there is no research report on the specific effects of CMV on fruit quality,which makes the research on the prevention and control of CMV in Passiflora edulis has become a major problem.Therefore,this paper first uses Passiflora edulis(Zixiang No.1)seedlings as experimental materials to establish an indoor CMV Passiflora edulis seedling live screening model;Then investigates the control effects of different chemical treatments and determines the fruit quality through outdoor field control experiments,and screen out 1-2 kinds of good anti-CMV agents;Furthermore,transcriptome sequencing and proteomics are used to screen out the differentially expressed genes,key differtial proteins and related metabolic pathways in different treatment groups to explore the mechanism of action of anti-CMV agents.The main research contents and results are as follows:(1)Indoor CMV-Passiflora edulis seedling screening in vivoIn vivo screening model of indoor CMV-Passiflora edulis has been established,after spraying48 hours,the CMV Agrobacterium friction inoculation is carried out.First,the toxic rate of samples in the different treatment groups has been detected by ordinary PCR.It is found that the CK group toxic rate is 91.7% and 50% in the 5%amino-oligosaccharin group,66.67% in the 30%Dufulin group,83.3% in the 8%Ningnanmycin group,58.3% in the 20%hydrochloride·morpholine guanidine group,and 83.3% in the 5.9%octylococcus·morlinguanidine group;the relative control effects are 45.48%,27.3%,9.17%,36.43% and 9.17%,respectively.The 5% amino-oligosaccharin treatment group has the highest control effect.Furthermore,The expression of CMV CP Gene is further detected by RT-q PCR,and the expression of CMV CP Gene in passion fruit.The results showed that the expression of CMV CP gene is the highest in CK group,which is 2.34;The lowest value is 0.23 in 5% amino-oligosaccharin group.Finally,the chlorophyll content and defensive enzyme activity of the different treatment groups are measured,and found that after CMV infection,the chlorophyll content and defensive enzyme activity of the CK control group is generally in a downward trend,and is lower than most treatment groups;5%amino-oligosaccharin treatment can significantly increase the chlorophyll content and regulate the activities of defense enzymes.(2)Field control experiment of different pesticides and their effects on the fruit quality of Passiflora edulisFive kinds of antiviral agents,including 5%amino-oligosaccharide,30%Dufulin,8%nin gnanmycin,20%hydrochloride·morlinguanidine and 5.9%octylococcus·morlinguanidine,are s elected to conduct field control experiments,the control effect of 5%amino-oligosaccharin and 20%hydrochloride·morpholinoguanidine is the highest,reaching 47.35% and 44.45%,re spectively.It is found that the chemical treatment had no significant effect on the fruit ap pearance quality.The treatment of 20%morpholinoguanidine hydrochloride and 5%amino-oli gosaccharin can significantly increase the antioxidant enzyme activity of the fruit,and the effect of improving disease resistance is significant;Among them,the treatmentof 5%amin o-oligosaccharin significantly improves the content of soluble solids,titratable acid,vitamin C,amino acid and organic acid in the fruit,it has the function of enhancing fruit quality.(3)Transcriptome sequencing analysis of different spray treatment groups of Passiflora edulisTranscriptome RNA-seq sequencing has performed on two pharmacological treatments of 5%amino-oligosaccharin(COS)and 20%morpholinoguanidine hydrochloride(Mor)with high er control effect.Compared with the CK group,the COS group shared the differentially e xpressed genes 911,557 up-regulated genes,354 down-regulated genes;Compared with C K group,Mor group had 1,149 differentially expressed genes,546 up-regulated genes,and down-regulated 603 genes;GO classification analysis of differential genes found,the differe ntially expressed genes of the COS group and the Mor group are involved in the three bi ological processes of defense response,redox process and protein phosphorylation;Both in volve protein binding and ATP binding two molecular functions;Among them,the differen tial genes in the COS group also mainly involve kinase activity and protein serine/threonin e kinase activity.KEGG pathway enrichment analysis of differential genes found that the t wo treatment groups were mainly enriched in Plant hormone signal transduction,MAPK si gnal pathway-plant,Plant pathogens interaction and Phenylpropanol biosynthesis.These met abolic pathways are associated with virus resistance.Key differential genes in the metaboli c pathway are screened for RT-q PCR verification,and the verification results are consistentwith the down-regulation of the transcriptome data.The gene expression levels in the CO S group and the MOR group are both up-regulated,and significantly different from those in the CK group.The two agents could significantly improve the expression levels of diff erent genes.(4)Proteomics study of different spraying treatment groups of Passiflora edulisUsing mass spectrometry to identify the proteins of different treated samples,it is found that962 proteins are identified in the CK group,and 240 are specifically expressed;884 proteins are identified in the 5%amino-oligosaccharin(COS)treatment group,and 193 are specifically expressed;862 proteins are identified in the 20% Morpholine hydrochloride(Mor)treatment group,and 128 are specifically expressed;among them,there are 694(54.81%)common proteins.The GO classification analysis of the differentially expressed proteins found that the differential proteins in the COS group mainly involved the molecular function of chlorophyll binding,and participated in the biological process of photosynthesis: light harvesting in photosystem I.Each GO classification is related to the photosynthesis process,indicating that the differentially expressed proteins in the COS treatment group are mainly involved in the photosynthetic pathway;The Mor group and the COS group have the most differential proteins concentrated in cell components,but the COS group is mainly localized to chloroplast related components.KEGG pathway enrichment analysis of differential proteins found that a total of 257 metabolic pathways are enriched,mainly enriched in Secondary metabolite biosynthesis,and Carbon fixation in photosynthetic organisms,Porphyrin and chlorophyll metabolism,Photosynthesis,Plant hormone signal transduction,Plant pathogen interaction,Phenylpropanoid biosynthesis and MAPK signaling pathway and other metabolisms path.The combined analysis of transcriptome sequencing and proteomics data found that the coexpressed psb A,atp F,and CAB21 proteins mainly act on the photosynthesis pathway.Among them,the psb A protein is up-regulated in the two treatment groups and the expression of CAB21 protein is down-regulated,but the atp F protein is only up-regulated in COS group.It shows that the treatment with COS has a protective effect on the photosynthesis mechanism and makes Passiflora edulis immune to CMV.