Accumulation of an ABA analogue in the wilty tomato mutant, flacca.

A new abscisic acid (ABA) analogue has been isolated from tomato plants. High levels of the compound are found in flacca mutants compared with normal isogenic controls. The analogue also accumulates in response to water stress. Three alternative structures, consistent with the mass spectrum, have been proposed. The possibility that the compound may be a biosynthetic precursor of ABA is considered.