Biosynthesis of (+)-abscisic acid in Cercospora cruenta.

Conformational Analysis of Abscisic Acid Analogs Produced by Cercospora cruenta.

The conformation of hydroxy-γ-ionylideneacetic acids produced by Cercospora cruenta was examined by 'H-NMR analysis. (1)H-(1)H COSY and NOE data indicated that (2Z,4E,1'R,4'#)-4'-hydroxy-(γ)- ionylideneacetic acid has a cyclohexane ring of chair form furnishing a hydroxyl group and a 2,4-pentadienoic acid moiety, each with equatorial orientation, while (2Z,4E,1'S,3'S)-3'-hydroxy-γ-ionylideneace...

Biosynthesis of abscisic acid by the direct pathway via ionylideneethane in a fungus, Cercospora cruenta.

We examined the biosynthetic pathway of abscisic acid (ABA) after isopentenyl diphosphate in a fungus, Cercospora cruenta. All oxygen atoms at C-1, -1, -1', and -4' of ABA produced by this fungus were labeled with (18)O from (18)O(2). The fungus did not produce the 9Z-carotenoid possessing gamma-ring that is likely a precursor for the carotenoid pathway, but produced new sesquiterpenoids, 2E,4E...

Influence of Nitrogen Source, Thiamine, and Light on Biosynthesis of Abscisic Acid by Cercospora rosicola Passerini.

Abscisic acid production by Cercospora rosicola Passerini in liquid shake culture was measured with different amino acids in combination and singly as nitrogen sources and with different amounts of thiamine in the media. Production of abscisic acid was highest with aspartic acid-glutamic acid and aspartic acid-glutamic acid-serine mixtures as nitrogen sources. Single amino acids that supported ...

Inhibition of Abscisic Acid Biosynthesis in Cercospora rosicola by Inhibitors of Gibberellin Biosynthesis and Plant Growth Retardants.

The fungus Cercospora rosicola produces abscisic acid (ABA) as a secondary metabolite. We developed a convenient system using this fungus to determine the effects of compounds on the biosynthesis of ABA. Inasmuch as ABA and the gibberellins (GAs) both arise via the isoprenoid pathway, it was of interest to determine if inhibitors of GA biosynthesis affect ABA biosynthesis. All five putative inh...

Abscisic Acid biosynthesis and response.