Table I.
Characteristics of the Arabidopsis mutants used in this study
| Ecotypes and Mutants | Gene Mutated | Deficiency |
|---|---|---|
| Columbia | ||
| Col (C) | None (WT) | |
| tt4-2YY6(Y) | CHS: A to G (non-coding region); splicing disrupted | CHS protein absent; increased sinapate esters; flavonoids absent |
| fah1 (F) | F5H | F5H enzyme absent; absence of sinapoylmalate, sinapoyl choline, and sinapate esters |
| Landsberg erecta | ||
| Ler (L) | None (WT) | |
| tt4-W85(W) | CHS: A to G (coding region) | CHS protein absent; flavonoids absent; increased sinapate esters |
| tt5 (T) | CHI: inversion | CHI protein absent; flavonoids absent; reduced sinapoylmalate |
The tt4-2YY6 allele contains a single nucleotide change (A to G transition) in a non-coding region that disrupts the splicing. There is no detectable CHS protein and flavonoids in these plants. The tt4-W85 allele contains a single nucleotide change in the coding region (A to G transition) that changes a Gly to a Ser residue. The levels of mRNA appear to be normal, but there are no detectable flavonoids in any tissue of these plants. The tt5 lesion consists of an inversion that results in reduced levels of mRNA and apparent loss of enzyme activity. There are no flavonoids in these plants. The fah1 mutant is modified on the F5H gene and lacks sinapate esters due to a deficiency in activity of F5H.