Genetic analysis of an attenuated Papaya ringspot virus strain applied for cross-protection

Chiang, Chu-Hui; Lee, Chun-Yee; Wang, Ching-Hsien; Jan, Fuh-Jyh; Lin, Shih-Shun; Chen, Tsung-Chi; Raja, Joseph A. J.; Yeh, Shyi-Dong

doi:10.1007/s10658-007-9130-z

Cited by 41 publications

(23 citation statements)

References 42 publications

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“…Based on sequence analysis, it has been hypothesized that the P1 protein has a role in adaptation to the host of potyviruses (Adams et al ., 2005; Valli et al ., 2007). In support of this hypothesis, nucleotide changes in the P1 sequence were associated with PPV adaptation and symptom modulation in N. clevelandii (Salvador et al ., 2008a), and with attenuation of Papaya ringspot virus in papaya (Chiang et al ., 2007). Furthermore, substitution of the PPV P1 cistron by the corresponding region of the Tobacco vein mottling virus (TVMV) genome did not affect PPV infectivity in common PPV/TVMV hosts, but did prevent infection of peach, which is not a host for TVMV (Salvador et al ., 2008b).…”

Section: Discussionmentioning

confidence: 99%

Virus variants with differences in the P1 protein coexist in a Plum pox virus population and display particular host‐dependent pathogenicity features

Maliogka

Salvador

Carbonell

et al. 2012

Molecular Plant Pathology

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SUMMARY Subisolates segregated from an M‐type Plum pox virus (PPV) isolate, PPV‐PS, differ widely in pathogenicity despite their high degree of sequence similarity. A single amino acid substitution, K109E, in the helper component proteinase (HCPro) protein of PPV caused a significant enhancement of symptom severity in herbaceous hosts, and notably modified virus infectivity in peach seedlings. The presence of this substitution in certain subisolates that induced mild symptoms in herbaceous hosts and did not infect peach seedlings suggested the existence of uncharacterized attenuating factors in these subisolates. In this study, we show that two amino acid changes in the P1 protein are specifically associated with the mild pathogenicity exhibited by some PS subisolates. Site‐directed mutagenesis studies demonstrated that both substitutions, W29R and V139E, but especially W29R, resulted in lower levels of virus accumulation and symptom severity in a woody host, Prunus persica. Furthermore, when W29R and V139E mutations were expressed concomitantly, PPV infectivity was completely abolished in this host. In contrast, the V139E substitution, but not W29R, was found to be responsible for symptom attenuation in herbaceous hosts. Deep sequencing analysis demonstrated that the W29R and V139E heterogeneities already existed in the original PPV‐PS isolate before its segregation in different subisolates by local lesion cloning. These results highlight the potential complexity of potyviral populations and the relevance of the P1 protein of potyviruses in pathogenesis and viral adaptation to the host.

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Section: Discussionmentioning

confidence: 99%

Virus variants with differences in the P1 protein coexist in a Plum pox virus population and display particular host‐dependent pathogenicity features

Maliogka

Salvador

Carbonell

et al. 2012

Molecular Plant Pathology

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“…1c, there are also reports of attenuated potyviruses (Chiang et al 2007;Lin et al 2007b;Yambao et al 2008). When an attenuated strain (HA5-1) of PRSV was compared with its parent strain HA using an infectious cDNA clone, two amino acid substitutions among three in the C-terminal region of P1 at aa positions 309 and 481, and two of four in HC-Pro at aa positions 753 and 944 of HA5-1 appear to be critical in symptom attenuation in papaya (Chiang et al 2007). In a comparison of attenuated and severe strains of Clover yellow vein virus (ClYVV), two amino acid substitutions in HC-Pro were found to be responsible for symptom attenuation (Yambao et al 2008).…”

Section: Potyvirusmentioning

confidence: 99%

Attenuated plant viruses: preventing virus diseases and understanding the molecular mechanism

Nishiguchi

Kobayashi

2011

J Gen Plant Pathol

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Attenuated viruses have been isolated and studied not only as a practical means of controlling virus diseases but also to gain a molecular understanding of viral virulence and cross protection. They have been isolated from crop fields and generated through high/low temperature treatment or by mutagens such as nitrous acid and ultraviolet irradiation. Some viruses have been beneficially used in fields and evaluated for one or more decades. Molecular genetic studies on attenuated viruses have revealed that amino acid substitutions are located in replicase and the movement protein in tobamovirus, protein 2b for cucumovirus, and P1 and HC-Pro for potyvirus. In most cases, with a few exceptions, symptom attenuation is positively correlated with a reduced level of RNA silencing suppression. Molecular mechanisms underlying virus attenuation and cross protection and the rationale for practical use of attenuated viruses for effective virus disease control are discussed.

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“…Once the mild strain has been inoculated it can trigger strain-or sequence-specific resistance against the challenge virus. Many researchers have found that mutations on viral silencing suppressors can attenuate severe symptoms, e.g., mutations in the silencing suppressor HC-Pro from potyvirus (Gal-On 2000; Chiang et al 2007;Lin et al 2007). In addition, mutations on the 126 kDa replicase, another silencing suppressor from the pepper mild mottle virus (PMMoV) resulted in attenuated symptoms and provided cross-protection on pepper plants (Yoon et al 2006).…”

Section: Cross-protectionmentioning

confidence: 99%

Strategies and mechanisms of plant virus resistance

Lin

Henriques

et al. 2007

Plant Biotechnol Rep

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Virus-induced diseases are responsible for major crop losses worldwide. A better understanding of plant defense mechanisms would lead to the development of novel strategies for effective plant protection. Early protein-based approaches relied mostly on the expression of transgenic coat protein (CP) to block the progression of the virus infectious process. Other strategies exploit the plant's innate defense mechanisms to combat invading viral pathogens. For example, the RNA-based resistance makes use of the plant post-transcriptional gene silencing (PTGS) mechanism to degrade viral RNAs. In cross-protection the prior inoculation with a mild viral strain confers resistance against a severe strain. Although the molecular detail of cross-protection is not fully understood, it is likely to be comprised of both protein-and RNA- based mechanisms, as well as some other unknown processes. In this review article we compare the benefits and challenges of these different viral-resistance approaches. Furthermore, we discuss the development of a new approach based on the plant's miRNA pathway. Artificial miRNAs with sequences complementary to viral sequences have been successfully used to generate virus resistance. This novel anti-viral strategy, which has the advantage of reducing possible bio-safety risks associated with protein-and RNA based strategies, is a first step toward designing environmentally friendly virus resistance in transgenic crops

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Genetic analysis of an attenuated Papaya ringspot virus strain applied for cross-protection

Cited by 41 publications

References 42 publications

Virus variants with differences in the P1 protein coexist in a Plum pox virus population and display particular host‐dependent pathogenicity features

Virus variants with differences in the P1 protein coexist in a Plum pox virus population and display particular host‐dependent pathogenicity features

Attenuated plant viruses: preventing virus diseases and understanding the molecular mechanism

Strategies and mechanisms of plant virus resistance

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