Field Evaluation of Transgenic White Clover with AMV Immunity and Development of Elite Transgenic Germplasm

Abstract

Viral diseases such as alfalfa mosaic virus (AMV) cause significant reductions in dry matter yield and persistency of white clover (Trifolium repens L.). Transgenic white clover plants expressing the AMV coat protein (AMV-CP) gene and showing immunity to AMV infection were evaluated in multi-site small-scale field releases. Two transformation events showing field immunity to aphid-mediated AMV infection This article outlines the development of transgenic elite white clover germplasm with AMV immunity, involving the world's first breeding nursery for transgenic white clover.were selected for elite transgenic germplasm development. Following top crosses with elite parental breeding lines, diallel crosses of heterozygous offspring plants and identification of AMV-CP homozygous T2 lines through quantitative PCR-based high-throughput screening, a breeding nursery with 1,300 transgenic white clover plants was established. Agronomically superior transgenic white clover plants were selected as parents for the production of world's first AMV immune transgenic white clover cultivars.

Alteration of plant species mixtures by virus infection: Managed pastures the forgotten dimension

“…The scarce funding remaining for pasture virus research was diverted to genetic engineering for virus resistance. For example, in Australia it was diverted into genetic modification of T. repens and M. truncatula for resistance to alfalfa mosaic virus (AMV; e.g., Emmerling et al, 2004;Jayasena et al, 2001;Panter et al, 2012). However, the genetically modified pasture plants developed were never sown in commercial pastures, and after that no further pasture virus research was funded.…”

“…repens and M . truncatula for resistance to alfalfa mosaic virus (AMV; e.g., Emmerling et al, 2004; Jayasena et al, 2001; Panter et al, 2012). However, the genetically modified pasture plants developed were never sown in commercial pastures, and after that no further pasture virus research was funded.…”

Assessment of nutritional characteristics of virus-resistant transgenic white clover (Trifolium repens L.) grown under field and glasshouse conditions

“…To our knowledge, there are no published biochemical data comparing GM white clover germplasm to similar non-GM germplasm, with a view towards biosafety assessment. Therefore, this study aimed to evaluate herbage samples from the 'Sustain'-type and 'Mink'-type AMV-resistant transgenic white clover lines developed through crossing a transgenic event into the white clover cultivars Grasslands Sustain and Mink respectively (Emmerling et al 2004;Panter et al 2011), and genetically similar wild-type control lines in terms of nutritive characteristics and secondary metabolite concentrations. Analysis of the data was expected to reveal whether the GM and non-GM control plants were substantially equivalent, or if the genetic modification caused an unintended negative effect on forage quality and therefore posed a biosafety risk.…”