Monday, March 14, 1994
By Roberta Friedman, Ph.D.
A published report of viral recombination in an engineered plant does not mean that
transgenic, virally resistant plant seeds should be shelved, scientists say. Instead, the
research points to ways of predicting that the release of such plants will be safe.
In the experiments reported in Science, Michigan State University researchers
engineered nicotiana plants to express the coat protein of the cowpea chloritic mottle
virus, missing one-third of its genome at the 3' end. The viral fragment didn't confer
viral resistance, but was an artificial construct to study viral recombination.
The researchers then attempted to infect the engineered plants by inoculating new
leaves with a construct consisting of the missing 3' end.
Four of 125 plants developed systemic infection, indicating that the two pieces of
viral RNA had combined and restored a functional capsid gene. The recombined RNA proved to
be slight variants of the original virus. A commentary in Science by plant biotech