Dissection of RNA-mediated ryegrass mosaic virus resistance in fertile transgenic perennial ryegrass (Lolium perenne L.)

Xu, JP Schubert, J Altpeter, F

Jp. Xu et al., Dissection of RNA-mediated ryegrass mosaic virus resistance in fertile transgenic perennial ryegrass (Lolium perenne L.), PLANT J, 26(3), 2001, pp. 265-274

42

INGLESE

Article

Plant Sciences","Animal & Plant Sciences

PLANT JOURNAL

0960-7412 → ACNP

26

3

2001

265 - 274

ISI

0960-7412(200105)26:3<265:DORRMV>2.0.ZU;2-4

Ryegrass mosaic virus (RgMV) frequently reduces yield and persistence of pe rennial ryegrass. We introduced an untranslatable RgMV coat protein (RgMV-C P) gene into perennial ryegrass using particle bombardment to explore the p otential of RNA-mediated virus resistance. Nine months after inoculation wi th the RgMV-Bulgaria strain, the most resistant transgenic line showed no i mmune-detectable RgMV-CP in all replications of the primary transformant an d a sexual progeny. A significant influence of the transgenic line, virus s train and the period after inoculation on the RgMV level was observed. Typi cal examples of recovery resistance from initially susceptible plants were not identified. Molecular analysis revealed RgMV resistance operates by tar geted RNA degradation resulting in post-transcriptional transgene silencing (PTGS) along with inhibition of virus RNA replication and was not associat ed with a threshold of transgene expression. Suppression of PTGS by RgMV di ffered significantly in two progenies with identical RgMV-CP transgene inte gration and a similar RgMV-CP transgene methylation pattern, suggesting the presence of quantitative components controlling the stability of PTGS in p erennial ryegrass. This study extends RNA-mediated virus resistance, post t ranscriptional gene silencing and crop improvement by genetic engineering t o an agronomically important perennial monocot.