ALS — Nicotiana attenuata

Summary

A4A49_23189 (ALS) in coyote tobacco (Nicotiana attenuata) encodes an acetolactate synthase, a thiamine pyrophosphate-dependent enzyme that catalyses the first committed step in branched-chain amino acid biosynthesis. The gene product possesses acetolactate synthase, pyruvate decarboxylase and 2-hydroxyacyl-CoA lyase activities, binds TPP, FAD and magnesium, and localises to the chloroplast stroma as part of the acetolactate synthase complex. ALS is associated with branched-chain amino acid anabolism, valine biosynthesis, fatty acid alpha-oxidation, secondary metabolism and response to herbicide. In this species, the IMR1 allele confers resistance to sulfonylurea and imidazolinone herbicides. The gene is also linked to herbicide tolerance via the G121A substitution. Studies of related genes in other species connect the family to imidazolinone and sulfonylurea sensitivity, amino acid and cellulose content, water use efficiency, root length, chlorophyll content, plant growth and seed production.