Spring wheat with scab-resistance transgene was not scab-resistant
and showed localized death of leaf tissue.
Spring wheat (Triticum aestivum L.), cultivar Bobwhite.
PR-2 and PR-3 genes for the pathogenesis-related
proteins, beta-1,3-glucanase and chitinase, respectively, derived from
the scab-resistant wheat cultivar Sumai-3. The genes were fused to the
maize ubiquitin promoter so that they would be expressed in all parts of
Make spring wheat resistant to scab (Fusarium, head blight),
a major disease.
Four of the twenty-four transgenic lines expressed either one or both
of the transgenes; these four lines showed stable inheritance of the
transgenes for up to four generations; one line (32A) showed reduced
scab infection under greenhouse conditions.
Transgene activity in twenty of the twenty-four transgenic lines (80%)
shut down after the initial generation, apparently due to gene silencing.
None of the plants from the four transgene-expressing lines was resistant
to scab infection under field conditions (including plants of Line 32A
that showed reduced scab infection under greenhouse conditions).
Plants of Line 32A, which had the highest transgene expression, also
suffered from a "lesion-mimic phenotype" in which the leaves developed
necrotic (tissue death) spots during flower formation (booting).
Anand, A., T. Zhou, H. N. Trick, B. S. Gill et al. (2003). "Greenhouse
and Field Testing of Transgenic Wheat Plants Stably Expressing Genes
for Thaumatin-like Protein, Chitinase and Glucanase against Fusarium
graminearum," Journal of Experimental Biology vol. 54,
Departments of Biochemistry and Plant Pathology, Kansas State University.
Kansas Wheat Commission and the U.S. Wheat and Barley Scab Initiative
Not on the market as of 2008.
Copyright 2008 The Nature