scholarly journals Two Amino Acid Substitutions in the Coat Protein of Pepper mild mottle virus Are Responsible for Overcoming the L4 Gene-Mediated Resistance in Capsicum spp.

2007 ◽  
Vol 97 (7) ◽  
pp. 787-793 ◽  
Author(s):  
Yoshikatsu Genda ◽  
Ayami Kanda ◽  
Hiroyuki Hamada ◽  
Kyoko Sato ◽  
Jun Ohnishi ◽  
...  
Keyword(s):  
Amino Acid ◽  
Coat Protein ◽  
Resistance Gene ◽  
Site Directed Mutagenesis ◽  
Mottle Virus ◽  
Amino Acid Substitutions ◽  
Pepper Mild Mottle Virus ◽  
Biological Assays ◽  
Capsicum Spp ◽  
Capsicum Chacoense

The Capsicum spp. L genes (L1 to L4) confer resistance to tobamoviruses. Currently, the L4 gene from Capsicum chacoense is the most effective resistance gene and has been used widely in breeding programs in Japan which have developed new resistant cultivars against Pepper mild mottle virus (PMMoV). However, in 2004, mild mosaic symptoms began appearing on the leaves of commercial pepper plants in the field which possessed the L4 resistance gene. Serological and biological assays on Capsicum spp. identified the causal virus strain as a previously unreported pathotype, P1,2,3,4. PMMoV sequence analysis of the virus and site-directed mutagenesis using a PMMoV-J of the P1,2 pathotype revealed that two amino acid substitutions in the coat protein, Gln to Arg at position 46 and Gly to Lys at position 85, were responsible for overcoming the L4 resistance gene.

scholarly journals Pepper Mild Mottle Virus Coat Protein Alone Can Elicit the Capsicum spp. L3 Gene-Mediated Resistance

1998 ◽  
Vol 11 (12) ◽  
pp. 1253-1257 ◽  
Author(s):  
P. Gilardi ◽  
I. García-Luque ◽  
M. T. Serra
Keyword(s):  
Coat Protein ◽  
Resistance Gene ◽  
Protein Gene ◽  
Expression System ◽  
Potato Virus X ◽  
Mottle Virus ◽  
Capsicum Chinense ◽  
Pepper Mild Mottle Virus ◽  
Capsicum Spp ◽  
Virus Coat

The pepper mild mottle virus (PMMoV-S) (an L3 hypersensitive response [HR]-inducer strain) coat protein was expressed in Capsicum chinense (L3L3) plants with the heterologous potato virus X (PVX)-based expression system. The chimeric virus was localized in the inoculated leaves and induced the HR, thus indicating that the tobamoviral sequences that affect induction of the HR conferred by the L3 resistance gene reside in the coat protein gene. Furthermore, transient expression of the PMMoV-S coat protein in C. chinense leaves by biolistic co-bombardment with a plasmid expressing the β-glucuronidase (GUS) gene leads to the induction of cell death and expression of host defense genes. Thus, the coat protein of PMMoV-S is the elicitor of the Capsicum spp. L3 resistance gene-mediated HR.

scholarly journals The Coat Protein Is Required for the Elicitation of the Capsicum L2 Gene-Mediated Resistance Against the Tobamoviruses

1997 ◽  
Vol 10 (1) ◽  
pp. 107-113 ◽  
Author(s):  
A. de la Cruz ◽  
L. López ◽  
F. Tenllado ◽  
J. R. Díaz-Ruíz ◽  
A. I. Sanz ◽  
...  
Keyword(s):  
Coat Protein ◽  
Resistance Gene ◽  
Coat Protein Gene ◽  
Protein Gene ◽  
Hypersensitive Reaction ◽  
Mottle Virus ◽  
Pepper Mild Mottle Virus ◽  
Factors Affecting ◽  
Viral Genomes ◽  
Capsicum Spp

In Capsicum, the resistance against tobamoviruses conferred by the L2 gene is effective against all but one of the known tobamoviruses. Pepper mild mottle virus (PMMoV) is the only virus which escapes its action. To identify the viral factors affecting induction of the hypersensitive reaction (HR) mediated by the Capsicum spp. L2 resistance gene, we have constructed chimeric viral genomes between paprika mild mottle virus (PaMMV) (a virus able to induce the HR) and PMMoV. A hybrid virus with the PaMMV coat protein gene substituted in the PMMoV-S sequences was able to elicit the HR in Capsicum frutescens (L2L2) plants. These data indicate that the sequences that affect induction of the HR mediated by the L2 resistance gene reside in the coat protein gene. Furthermore, a mutant that codes for a truncated coat protein was able to systemically spread in these plants. Thus, the elicitation of the host response requires the coat protein and not the RNA.

Amino Acid Changes in Pepper mild mottle virus Coat Protein That Affect L 3 Gene-mediated Resistance in Pepper

2002 ◽  
Vol 68 (2) ◽  
pp. 155-162 ◽  
Author(s):  
Hiroyuki HAMADA ◽  
Shigeharu TAKEUCHI ◽  
Akinori KIBA ◽  
Shinya TSUDA ◽  
Yasufumi HIKICHI ◽  
...  
Keyword(s):  
Amino Acid ◽  
Coat Protein ◽  
Mottle Virus ◽  
Pepper Mild Mottle Virus ◽  
Virus Coat Protein ◽  
Virus Coat

Cooperative effect of two amino acid mutations in the coat protein of Pepper mild mottle virus overcomes L 3 -mediated resistance in Capsicum plants

Virus Genes ◽  
2006 ◽  
Vol 34 (2) ◽  
pp. 205-214 ◽  
Author(s):  
Hiroyuki Hamada ◽  
Reiko Tomita ◽  
Yasuya Iwadate ◽  
Kappei Kobayashi ◽  
Ikuko Munemura ◽  
...  
Keyword(s):  
Amino Acid ◽  
Coat Protein ◽  
Cooperative Effect ◽  
Mottle Virus ◽  
Pepper Mild Mottle Virus ◽  
Amino Acid Mutations

scholarly journals Symptom induction by Cowpea chlorotic mottle virus on Vigna unguiculata is determined by amino acid residue 151 in the coat protein

2002 ◽  
Vol 83 (4) ◽  
pp. 879-883 ◽  
Author(s):  
F. M. de Assis Filho ◽  
O. R. Paguio ◽  
J. L. Sherwood ◽  
C. M. Deom
Keyword(s):  
Amino Acid ◽  
Coat Protein ◽  
Vigna Unguiculata ◽  
Amino Acid Residue ◽  
Site Directed Mutagenesis ◽  
Mottle Virus ◽  
Cdna Clones ◽  
Cowpea Chlorotic Mottle Virus ◽  
Chlorotic Mottle Virus ◽  
Chlorotic Mottle

The type strain of Cowpea chlorotic mottle virus (CCMV-T) produces a bright chlorosis in cowpea (Vigna unguiculata cv. California Blackeye). The attenuated variant (CCMV-M) induces mild green mottle symptoms that were previously mapped to RNA 3. Restriction fragment exchanges between RNA 3 cDNA clones of CCMV-T and CCMV-M that generate infectious transcripts and site-directed mutagenesis indicated that the codon encoding amino acid residue 151 of the coat protein determines the symptom phenotypes of CCMV-T and CCMV-M. Amino acid 151 is within an α-helical structure required for calcium ion binding and virus particle stability. No differences in virion stability or accumulation were detected between CCMV-T and CCMV-M. Mutational analysis suggested that the amino acid at position 151 and not the nucleotide sequence induce the symptom phenotype. Thus, it is likely that subtle influences by amino acid residue 151 in coat protein–host interactions result in chlorotic and mild green mottle symptoms.

scholarly journals The coat protein of tobamovirus acts as elicitor of both L 2 and L 4 gene-mediated resistance in Capsicum

2004 ◽  
Vol 85 (7) ◽  
pp. 2077-2085 ◽  
Author(s):  
P. Gilardi ◽  
I. García-Luque ◽  
M. T. Serra
Keyword(s):  
Hypersensitive Response ◽  
Host Response ◽  
Expression System ◽  
Potato Virus X ◽  
Mottle Virus ◽  
Coat Proteins ◽  
Pepper Mild Mottle Virus ◽  
Defence Genes ◽  
Glucuronidase Reporter ◽  
Capsicum Chacoense

In Capsicum, the resistance conferred by the L 2 gene is effective against all of the pepper-infecting tobamoviruses except Pepper mild mottle virus (PMMoV), whereas that conferred by the L 4 gene is effective against them all. These resistances are expressed by a hypersensitive response, manifested through the formation of necrotic local lesions (NLLs) at the primary site of infection. The Capsicum L 2 gene confers resistance to Paprika mild mottle virus (PaMMV), while the L 4 gene is effective against both PaMMV and PMMoV. The PaMMV and PMMoV coat proteins (CPs) were expressed in Capsicum frutescens (L 2 L 2) and Capsicum chacoense (L 4 L 4) plants using the heterologous Potato virus X (PVX)-based expression system. In C. frutescens (L 2 L 2) plants, the chimeric PVX virus containing the PaMMV CP was localized in the inoculated leaves and produced NLLs, whereas the chimeric PVX containing the PMMoV CP infected the plants systemically. Thus, the data indicated that the PaMMV CP is the only tobamovirus factor required for the induction of the host response mediated by the Capsicum L 2 resistance gene. In C. chacoense (L 4 L 4) plants, both chimeric viruses were localized to the inoculated leaves and produced NLLs, indicating that either PaMMV or PMMoV CPs are required to elicit the L 4 gene-mediated host response. In addition, transient expression of PaMMV CP into C. frutescens (L 2 L 2) leaves and PMMoV CP into C. chacoense (L 4 L 4) leaves by biolistic co-bombardment with a β-glucuronidase reporter gene led to the induction of cell death and the expression of host defence genes in both hosts. Thus, the tobamovirus CP is the elicitor of the Capsicum L 2 and L 4 gene-mediated hypersensitive response.

Kazakh strains of tobacco mosaic virus: two strains with potentially destabilizing amino acid substitutions in the coat protein

2000 ◽  
Vol 56 (2) ◽  
pp. 71-77 ◽  
Author(s):  
VICTOR K. NOVIKOV ◽  
EKATERINA V. BELENOVICH ◽  
EVGENY N. DOBROV ◽  
SERGEI K. ZAVRIEV
Keyword(s):  
Amino Acid ◽  
Coat Protein ◽  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Amino Acid Substitutions

scholarly journals Comparing mutagenesis and simulations as tools for identifying functionally important sequence changes for protein thermal adaptation

2018 ◽  
Vol 116 (2) ◽  
pp. 679-688 ◽  
Author(s):  
Ming-ling Liao ◽  
George N. Somero ◽  
Yun-wei Dong
Keyword(s):  
Amino Acid ◽  
Thermal Adaptation ◽  
Site Directed Mutagenesis ◽  
Dynamics Simulation ◽  
Amino Acid Substitutions ◽  
Thermal Stabilities ◽  
Specific Amino Acid ◽  
Enzyme Thermal Stability ◽  
And Function

Comparative studies of orthologous proteins of species evolved at different temperatures have revealed consistent patterns of temperature-related variation in thermal stabilities of structure and function. However, the precise mechanisms by which interspecific variations in sequence foster these adaptive changes remain largely unknown. Here, we compare orthologs of cytosolic malate dehydrogenase (cMDH) from marine molluscs adapted to temperatures ranging from −1.9 °C (Antarctica) to ∼55 °C (South China coast) and show how amino acid usage in different regions of the enzyme (surface, intermediate depth, and protein core) varies with adaptation temperature. This eukaryotic enzyme follows some but not all of the rules established in comparisons of archaeal and bacterial proteins. To link the effects of specific amino acid substitutions with adaptive variations in enzyme thermal stability, we combined site-directed mutagenesis (SDM) and in vitro protein experimentation with in silico mutagenesis using molecular dynamics simulation (MDS) techniques. SDM and MDS methods generally but not invariably yielded common effects on protein stability. MDS analysis is shown to provide insights into how specific amino acid substitutions affect the conformational flexibilities of mobile regions (MRs) of the enzyme that are essential for binding and catalysis. Whereas these substitutions invariably lie outside of the MRs, they effectively transmit their flexibility-modulating effects to the MRs through linked interactions among surface residues. This discovery illustrates that regions of the protein surface lying outside of the site of catalysis can help establish an enzyme’s thermal responses and foster evolutionary adaptation of function.

scholarly journals Functional effects of single amino acid substitutions in the region of Phe113 to Asp138 in the plasminogen activator inhibitor 1 molecule

1998 ◽  
Vol 331 (2) ◽  
pp. 409-415 ◽  
Author(s):  
Guang-Chao SUI ◽  
Björn WIMAN
Keyword(s):  
Amino Acid ◽  
Plasminogen Activator ◽  
Plasminogen Activator Inhibitor ◽  
Site Directed Mutagenesis ◽  
Single Amino Acid ◽  
Amino Acid Substitutions ◽  
Plasminogen Activator Inhibitor 1 ◽  
Low Activity ◽  
Activator Inhibitor ◽  
Pai 1

Thirteen amino acid substitutions have been introduced within the stretch Phe113 to Asp138 in the plasminogen activator inhibitor 1 (PAI-1) molecule by site-directed mutagenesis. The different proteins and wild-type (wt) PAI-1 have been overexpressed in Escherichia coliand purified by chromatography on heparin–Sepharose and on anhydrotrypsin–agarose. The PAI-1 variants have been characterized by their reactivity with tissue plasminogen activator (tPA), interactions with vitronectin or heparin, and stability. Most PAI-1 variants, except for Asp125 → Lys, Phe126 → Ser and Arg133 → Asp, displayed a high spontaneous inhibitory activity towards tPA, which did not change greatly on reactivation with 4 M guanidinium chloride, followed by dialysis at pH 5.5. The variants Asp125 → Lys and Arg133 → Asp became much more active after reactivation and they were also more rapidly transformed to inactive forms (t½ 22–31 min) at physiological pH and temperature than the other variants. However, in the presence of vitronectin they were both almost equally stable (t½ 2.3 h) as wtPAI-1 (t½ 3.0 h). The mutant Glu130 → Lys showed an increased stability, both in the absence and in the presence of vitronectin compared with wtPAI-1. Nevertheless a similar affinity between all the active PAI-1 variants and vitronectin was observed. Further, all mutants, including the three mutants with low activity, were to a large extent adsorbed on anhydrotrypsin–agarose and were eluted in a similar fashion. In accordance with these data, the three variants with a low activity were all to a large extent cleaved as a result of their reaction with tPA, suggesting that they occurred predominantly in the substrate conformation. Our results do not support the presence of a binding site for vitronectin in this part of the molecule, but rather that it might be involved in controlling the active PAI-1 to substrate transition. Partly, this region of the PAI-1 molecule (Arg115 to Arg118) seems also to be involved in the binding of heparin to PAI-1.

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