The protein kinase A/protein kinase G/protein kinase C-family (AGC kinase family) of eukaryotes is involved in regulating numerous biological processes. The 3-phosphoinositide- dependent protein kinase 1 (PDK1), is a conserved serine/threonine kinase in eukaryotes. To understand the roles of PDK1 homologous genes in cell death and immunity in tetraploid Nicotiana tabacum, the previuosly generated transgenic CRISPR/Cas9 lines, in which 5-7 alleles of the 4 homologous PDK1 genes (NtPDK1a/1b/1c/1d homologs) simultaneously knocked out, were used in this study. Our results showed that the hypersensitive response (HR) triggered by transient overexpression of active Pto (Pto^Y207D) or soybean GmMEKK1 was significantly delayed, whereas the resistance to Pseudomonas syrangae pv. tomato DC3000 (Pst DC3000) and tobacco mosaic virus (TMV) was significantly elevated in these partial knockout lines. The elevated resistance to Pst DC3000 and TMV was correlated with the elevated activation of NtMPK6, NtMPK3, and NtMPK4. Taken together, our results indicated that NtPDK1s play a positive role in cell death but a positive role in disease resistance, likely through negative regulation of the MAPK signaling cascade.
Nicotiana/virology* ; Disease Resistance/genetics* ; Plant Diseases/immunology* ; Plants, Genetically Modified/genetics* ; Gene Knockout Techniques ; Plant Proteins/genetics* ; CRISPR-Cas Systems ; Protein Serine-Threonine Kinases/genetics* ; 3-Phosphoinositide-Dependent Protein Kinases/genetics* ; Pyruvate Dehydrogenase Acetyl-Transferring Kinase ; Tobacco Mosaic Virus/pathogenicity*

Aims: The cucumber mosaic virus (CMV) is categorized under the genus Cucumovirus and family Bromoviridae. This virus is known to infect over 1200 plant species from 100 families, including ornamental and horticultural plants. In this study, we pioneered a global genome comparison to decipher the unknown orchestrators behind the virulence and pathogenicity of CMV via the discovery of important single nucleotide polymorphic markers. Methodology and results: As a result, the genome size was found to be a potential preliminary country-specific marker for South Korea and the GC content can be utilized to preliminarily differentiate Turkey isolates from the others. The motif analysis as well as whole genome and coat protein phylogenetic trees were unable to form country-specific clusters. However, the coat protein haplotype analysis had successfully unconcealed country-specific single nucleotide polymorphic markers for Iran, Turkey and Japan isolates. Moreover, coat protein modelling and gene ontology prediction depicted high conservation across CMV isolates from different countries. Conclusion, significance and impact of study The country-specific single nucleotide polymorphic markers unearthed in this study may provide significant data towards the profiling of varying virulence and pathogenicity of CMV across the globe in time to combat the yield loss driven by this virus thru the most efficacious biological control measures in the future.
Cucumovirus--genetics ; Genome, Microbial

Soybean mosaic virus (SMV), one of the major viral diseases of Pinellia ternata (Thunb.) Breit., has had a serious impact on its yield and quality. The construction of viral infectious clones is a powerful tool for reverse genetics research on viral gene function and interaction between virus and host. To clarify the molecular mechanism of SMV infection in Pinellia ternata, it is particularly important to construct the SMV full-length cDNA infectious clone. Therefore, the infectious clone of Soybean mosaic virus Shanxi Pinellia ternata isolate (SMV-SXBX) was constructed in this study by Gibson in vitro recombination system, and the healthy Pinellia ternata leaves were inoculated by Agrobacterium infiltration, further through mechanical passage and RT-PCR, confirming that the 3' end of the SMV-SXBX infectious clone had a stable infectivity when it contained 56-nt of poly(A) tail. This method is not only convenient and efficient, but also avoids the instability of SMV infectious clones in Escherichia coli. The construction of SMV full-length infectious cDNA clones laid the foundation for further study on the molecular mechanism of SMV replication and pathogenesis.
DNA, Complementary ; Pinellia ; virology ; Plant Diseases ; virology ; Potyvirus ; isolation & purification ; metabolism

A new isoquinoline alkaloid(1) has been isolated from the whole plant of Thalictrum glandulosissimum by using various chromatographic techniques, including silica gel, sephadex, MCI-gel resin, and RP-HPLC, and its structure was determined as 1-(6-hydroxy-7-methylisoquinolin-1-yl) ethantone by physicochemical properties and spectroscopic data. This compound was evaluated for anti-tobacco mosaic virus(TMV) activity. The results showed that it had prominent anti-TMV activity with inhibition rates of 28.4%. This rate was closed to that of positive control.
Alkaloids ; Antiviral Agents ; Isoquinolines ; Thalictrum ; Tobacco Mosaic Virus

Native turnip yellow mosaic virus (TYMV) is relatively unreactive to maleimide agents, indicating few reactive thiol groups on TYMV. In the present study, we aimed to construct TYMV mutants that have reactive cysteine residues on the surface. To this end, we prepared a library of TYMV mutants where the Thr residue at the C-terminus of coat protein (CP) was replaced by a random sequence of six amino acids that included one cysteine. This library was introduced into Nicotiana benthamiana by agroinfiltration. The CP sequence of the TYMV RNA isolated from inoculated leaves was amplified by reverse transcription-PCR and then used to construct a second library. This process was repeated one more time, and the CP sequences of the TYMV RNA in the inoculated leaves were analyzed. Based on the analysis of over 11,000 CP sequences, the Cys mutants representing most abundant TYMV RNAs were constructed. Analysis of the mutants showed that four Cys mutants were nearly comparable to wildtype with respect to CP and viral RNA levels in N. benthamiana. All these mutants were highly reactive to fluoresceine-5-maleimide. This demonstrates that TYMV can be modified to have additional functional groups on the surface that would be useful for drug delivery.
Amino Acids ; Brassica napus* ; Cysteine ; RNA ; RNA, Viral ; Tobacco ; Tymovirus*

A new naphthaldehyde derivative has been isolated from Comastoma pulmonarium by using various chromatographic techniques, including silica gel, Sephadex LH-20, MCI-gel resin and RP-HPLC. This compounds was determined as 5-methoxy-2-methyl-7-(2-oxopropyl)naphthalene-1-carbaldehyde(1) by NMR, MS, IR and UV spectra. This compound was also evaluated for its anti-tobacco mosaic virus (anti-TMV) activity. The result showed that it showed high anti-TMV activity with inhibition rate of 32.8%. The inhibition rate is close to that of positive control (ningnanmycin).
Aldehydes ; isolation & purification ; pharmacology ; Antiviral Agents ; isolation & purification ; pharmacology ; Chromatography, High Pressure Liquid ; Gentianaceae ; chemistry ; Naphthalenes ; isolation & purification ; pharmacology ; Phytochemicals ; isolation & purification ; pharmacology ; Tobacco ; Tobacco Mosaic Virus ; drug effects

It was previously observed that recombinant flock house virus (FHV) RNA1 was efficiently packaged into turnip yellow mosaic virus (TYMV), provided that the TYMV coat protein (CP) sequence was present at the 3′-end. FHV RNA encapsidated by TYMV CPs also had a four-nucleotide extension at the 5′-end. Since even a short extension at the 5′- and 3′-ends of FHV RNA1 inhibits replication, we examined whether the recombinant FHV RNA is indeed capable of replication. To this end, we introduced constructs expressing recombinant FHV RNAs into the plant Nicotiana benthamiana. Northern blot analysis of inoculated leaves suggested abundant production of recombinant FHV RNA1 and its subgenomic RNA. This demonstrated that recombinant FHV RNA with terminal extensions at both ends was competent for replication. We also showed that the recombinant FHV RNA can express the reporter gene encoding enhanced green fluorescent protein.
Blotting, Northern ; Brassica napus* ; Capsid Proteins* ; Genes, Reporter ; Plants ; RNA* ; Tobacco* ; Tymovirus*

Turnip yellow mosaic virus (TYMV) is a non-enveloped icosahedral virus composed of 20 kDa single coat proteins. In this study, we modified the TYMV coat protein (CP) ORF by inserting an oligonucleotide linker corresponding to T7, HSV, Tat, (Arg)9, or (RxR)4 peptide at the 5'-end of the CP ORF and examined its effect on replication, RNA packaging, and virion assembly. The results showed that the constructs containing (Arg)9 and (RxR)4 sequences were barely capable of replication. The TYMV constructs containing T7 and Tat peptide produced virions that co-migrated with wild-type virions. However, the insertion of T7 and Tat sequences impaired genomic RNA (gRNA) accumulation and packaging, respectively. When only the CP gene was expressed, CPs with (Arg)9 or (RxR)4 successfully produced virus-like particles whose mobility was comparable to that of wild type. In the case of CP having a HSV tag, the virion band was not detected, although a sufficient amount of CP was produced. This indicates that CP with the HSV tag failed to assemble into virions. Overall, the results suggest that TYMV replication, RNA packaging and virion assembly are strongly influenced by the insertion sequence.
Animals ; Brassica napus* ; Capsid Proteins ; Ecthyma, Contagious ; Product Packaging* ; RNA* ; Tymovirus* ; Virion*

A phytochemical investigation on the stems of Garcinia bracteata collected from Xishuangbanna resulted in the isolation of a new flavone. By analysis of the HRESIMS, IR, UV, 1D and 2D NMR spectra, the structure of the new compound was determined as 7-methoxy-4',6-dihydroxy-8-isobutyryl-flavone(1). Compound 1 was also tested for its anti-tobacco mosaic virus(TMV) activity. Results suggested the 1 possessed remarkable anti-TMV activity, with an inhibition rate of 28.2%.
Antiviral Agents ; chemistry ; isolation & purification ; pharmacology ; Drugs, Chinese Herbal ; chemistry ; isolation & purification ; pharmacology ; Flavones ; chemistry ; isolation & purification ; pharmacology ; Garcinia ; chemistry ; Magnetic Resonance Spectroscopy ; Plant Leaves ; chemistry ; Tobacco Mosaic Virus ; drug effects ; growth & development

Turnip yellow mosaic virus (TYMV) is a spherical plant virus that has a single 6.3 kb positive strand RNA as a genome. Previously, we have made the recombinant TYMV construct containing a 0.7 kb eGFP gene or a 1.8 kb GUS gene. The genomic RNAs from these constructs were efficiently encapsidated. To examine in more detail whether size constraint exists for replication and packaging of TYMV, we have inserted into the TY-GUS an extra sequence derived from either eGFP or GUS. We also made a recombinant containing RNA1 sequence of Flock house virus. These TYMV recombinants were introduced into Nicotiana benthamiana leaves by agroinfiltration. Northern blot analysis of the viral RNAs in the agroinfiltrated leaves showed that the genomic RNA band from the recombinant TYMV became weaker as longer sequence was inserted. The result also showed that the efficiency of genomic RNA encapsidation decreased sharply when an extra sequence of 2.2 kb or more was inserted. In contrast, the recombinant subgenomic RNA containing an extra sequence of up to 3.2 kb was efficiently encapsidated. Overall, these results show that size constraint exists for replication and encapsidation of TYMV RNA.
Blotting, Northern ; Genome ; Genome Size* ; Plant Viruses ; Product Packaging* ; RNA ; RNA, Viral ; Tobacco ; Tymovirus*