Biological Characteristics Of TeMV And Omics Analysis Of Passiflora Edulis Infected By TeMV

Telosma mosaic virus（Te MV）,a representative member of the genus Potyvirus,was a single-stranded RNA（ss RNA）plant viruses.Symptoms of Passiflora edulis infected by Te MV including:leaf mosaic,mottling,wrinkling,fruit lignifying and plant dwarfing.After reported this virus from passionflower host in Fujian Province,China in 2017.Te MV present to passionflower-producing areas in China and reduced production and quality.In this study,the biology and molecular characterization of three Te MV isolates have been analyzed.In addition,we used transcriptome and metabolomics to explore differentially expressed genes and metabolites from infected and control samples.The results could provide important theoretical to support the molecular mechanism of virus pathogenesis and host response mechanism.The main results are as follows:1.Three complete genome sequences of Te MV isolates（XW,RJ and YD）were obtained in this study（NCBI entry number:ON932194,ON932195,ON932196）.Excluding the poly（A）tail,the complete genome sequence of these Te MV isolates were 10069 nt,and encoding a polyprotein at190-9815 nt of the genome.Sequence identical analysis indicated that XW,RJ and YD isolates shared 98.1%-98.6%nucleotide and 98.8%-99.3%amino acid sequence identities to each other;shared 87.3%-98.9%nucleotide and 91.2%-99.5%amino acid sequence identities with other reference Te MV isolates from NCBI.And the three sequences had the highest consistency with the Wuyishan isolate（MK340755）.Phylogenetic analysis based on CP gene showed that Te MV isolates from the same host had a closer evolutionary relationship,indicating that the genetic evolution of the virus was related to different plant hosts.2.Specific primer was designed based on the conserved region of Viral protein genome-linked（VPg）,which can specifically amplify the 6483-6675 nt region of Te MV genome.This system established with the primers showed a good linear relationship,its amplification efficiency was102.77%,R²=0.9961,and the detection limit of the method was 2.370×10² copies·μL^-1,which was1000 folds higher than regular RT-PCR.Moreover,using the method to detect Te MV in 76 passion fruit samples,the results showed that the detection rate of Te MV was 93.4%.Thus,this technology is a powerful method to detect the Te MV and it will be valuable for further research.3.The biological characteristics of Te MV Gannan isolates were studied by mechanical inoculation.The results showed that Te MV could infect Passiflora edulis,Chenopodium amaranticolor,Nicotiana benthamiana,Chenopodium quinoa,Pisum sativum and Phaseolus vulgaris under laboratory conditions,and it was the first time we found Pisum sativum can infected by Te MV.Analyzing the virus accumulation at different temperatures after inoculation,the results showed that Te MV could be detected at three days,and accumulated the infection rate in leaves faster in 26-28℃than other temperatures,and the symptoms were highly correlated with the accumulation of virus.4.Transcriptome and metabolomics were performed in treatment group inoculated with isolate RJ and the control group inoculated with PBS.The results showed that the difference of 506 genes and 344 metabolites between treated and control group.The results showed the gene expression significant difference enriched in linoleic acid metabolism,α-linolenic acid metabolism,plant hormone signal transduction,MAPK signaling pathway-plant;The metabolites significant difference enriched in linoleic acid metabolism,α-linolenic acid metabolism,phenylalanine synthesis,fructose metabolism and other pathways.In this study,major in the jasmonic acid pathway ofα-linolenic acid metabolic pathway,and detected the content of jasmonic acid in the leaves of passionflower.Which showed the content of jasmonic acid of plant infected with Te MV was significantly higher than control group within 24 days,so jasmonic acid signaling pathway could involve in the resistance of Passiflora edulis to Te MV infection.