Post-transcriptional gene silencing as an efficient tool for engineering resistance to white clover mosaic virus in white clover (Trifolium repens)

Transgenic Nicotiana benthamiana plants expressing an untranslatable version of the coat protein (CP) gene from the Tamarillo mosaic virus (TaMV) were either resistant to TaMV infection or recovered from infection. These phenotypes were the result of a post-transcriptional gene silencing (PTGS) mechanism that targeted TaMV-CP sequences for degradation. The TaMV-CP sequences were degraded when present in the wild-type TaMV potyvirus, in transgene mRNA, or in chimeric viral vectors based on White clover mosaic virus. The more efficiently targeted region was mapped to a 134-nt segment. Differences were observed in the efficiency of targeting during cell-to-cell and long-distance movement of the chimeric viruses. However, the TaMV-CP sequences do not appear to be targeted for degradation when delivered by biolistics.

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The effect of white clover mosaic virus on nodulation of white clover (Trifolium repens L. cv. Ladino)

Australian Journal of Agricultural Research ◽

10.1071/ar9800307 ◽

1980 ◽

Vol 31 (2) ◽

pp. 307 ◽

Cited By ~ 18

Author(s):

P Guy ◽

A Gibbs ◽

K Harrower

Keyword(s):

Virus Infection ◽

Mosaic Virus ◽

White Clover ◽

Trifolium Repens ◽

Effective Strain ◽

Plant Weight ◽

Trifolium Repens L ◽

White Clover Mosaic Virus ◽

Infected Nodule ◽

Mosaic Virus Infection

White clover mosaic virus infection of Ladino clover seedlings resulted in decreased plant weight and a 71 % decrease in the number of nodules per plant without the decrease in nodule size which is usually observed when legumes are virus-infected. Nodule numbers decreased both on plants nodulated with an effective strain and on those with an ineffective strain of Rhizobium.

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Highways for internal virus spread: patterns of virus movement in the stoloniferous herb Trifolium repens

Botany ◽

10.1139/b11-044 ◽

2011 ◽

Vol 89 (8) ◽

pp. 573-579 ◽

Cited By ~ 1

Author(s):

Tamara van Mölken ◽

Thomas Sundelin ◽

Reinier Snetselaar ◽

Josef F. Stuefer

Keyword(s):

Mosaic Virus ◽

White Clover ◽

Trifolium Repens ◽

Resource Sharing ◽

Clonal Growth ◽

Physiological Integration ◽

Disease Development ◽

Virus Spread ◽

Leaf Ontogeny ◽

White Clover Mosaic Virus

Resource sharing between connected ramets can be advantageous for clonal plants. However, widespread vascular integration bears the risks of enhanced internal pathogen spread, which may be one of the most prominent disadvantages of clonal growth. In this paper we analyzed patterns of internal virus spread in ramet groups of the stoloniferous herb Trifolium repens L. (white clover) and investigated the effect of leaf ontogeny on intraclonal disease development. We inoculated single leaves of T. repens with White clover mosaic virus and analyzed the infection status of ramets at different distances from the point of infection and in leaves from different developmental stages. White clover mosaic virus infected all young developing plant parts positioned on basal branches or on the main stolon. Leaf ontogeny strongly affected disease development, and fully mature leaves on the main stolon remained virus free. The pattern of plant-internal virus spread was not affected by heterogeneous light conditions. Despite the well-described advantages of physiological integration, our data suggest that clonal integration may lead to negative selection pressures on clonal growth in pathogen-prone environments.

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