Expression of engineered wheat dwarf virus in seed‐derived embryos

Abstract

Delivery of DNA into dry and viable embryos of wheat by imbibition in DNA solution was detected by monitoring the transient expression of chimeric genes. The gene expression vectors used comprise of a neomycin phosphotransferase II (NPT II) reporter gene, under the control of various promoters or as part of a cloned plant virus genome. The genome of wheat dwarf virus (WDV), a monopartite Gemini virus of gramineae, has been used to amplify the NPT II gene in embryos of wheat, thereby leading to high levels of transient expression. Constructions were designed which permitted NPT II expression only if inter‐ or intramolecular recombination had occurred.

Inducible Resistance to Maize Streak Virus

“…In contrast, it is difficult to definitively prove this using the micro-projectile bombardment transformation system and the SGCs utilised in this study. Firstly, in the absence of MSV Rep protein, in situ recombination of the SGC (most likely at the repeated stem-loop sequences) may occur in a small number of cells [20] , [54] – [56] and this, in turn, could generate an episomal form of the cassette from which Rep can be expressed. Despite this possibility we were unable to detect SGC-encoded mutant rep transcripts in the absence of the MSV Rep protein (data not shown), suggesting these transcript levels are below the limit of detection by qPCR.…”

Gene Transfer to Plants: Assessment of Published Approaches and Results

“…Whereas in the previous experimental protocol one could envisage even recovery of transgenic cell clones (from protoplasts within opened cells), this is difficult to conceive in the following approach (82,83) unless DNA moves freely into and between cells. The authors describe experiments in which every precaution was taken to avoid the experimental pitfalls of earlier reports (52, 53).…”