Plant height and flowering were altered in alfalfa genetically
engineered to reduce lignin content.
Alfalfa (Medicago sativa)
Antisense sequences of genes involved in lignin synthesis (C3H, C4H,
F5H, and HCT), taken either from alfalfa or a closely related species
(M. truncatula). The gene construct included the bean promoter
Improve the digestibility of alfalfa by reducing its lignin content or
altering its lignin composition. Antisense sequences were used in an
attempt to suppress enzyme expression.
Genetically engineered (GE) lines were created with reduced enzyme
activity and lowered lignin content.
Many of the GE lines were only 25-50% as tall as the parent line.
Flowering was delayed in the GE lines, sometimes by as much as 20 days
compared with the parent line.
In some GE lines the flowers were white instead of their normal
The researchers even reported a different floral scent for one of the
Reddy, M. S. S., F. Chen, G. Shadle, L. Jackson et al. (2005). "Targeted
Down-regulation of Cytochrome P450 Enzymes for Forage Quality Improvement
in Alfalfa (Medicago sativa L.)," Proceedings of the National
Academy of Sciences vol. 102, pp. 16573-8.
Shadle, G., F. Chen, M. S. S. Reddy, L. Jackson et al. (2007).
"Down-regulation of Hydroxycinnamoyl CoA: Shikimate Hydroxycinnamoyl
Transferase in Transgenic Alfalfa Affects Lignification, Development
and Forage Quality," Phytochemistry vol. 68, pp. 1521-9.
Samuel Roberts Noble Foundation, Ardmore, Oklahoma.
Forage Genetics International and the Samuel Roberts Noble Foundation.
Not on the market as of April, 2009.
Copyright 2009 The Nature