There is evidence that the first tetraterpene formed in carotenoid biosynthesis is not lycopersene, the C40 analogue of squalene, but phytoene (15,15'-dehydrolycopersene). Davies, Goodwin & Mercer (1961) failed to find lycopersene in any carotenogenic system they examined, and it was suggested that lycopersene plays no part in carotenoid biosynthesis (Davies, 1961, 1962; Goodwin, 1961). Mercer,...

Previous complementation and mapping of mutations that change the usual yellow color of the Zygomycete Phycomyces blakesleeanus to white or red led to the definition of two structural genes for carotene biosynthesis. We have cloned one of these genes, carRA, by taking advantage of its close linkage to the other, carB, responsible for phytoene dehydrogenase. The sequences of the wild type and si...

Carotenoids play an integral and essential role in photosynthesis and photoprotection in plants and algae. A collection of Chlamydomonas reinhardtii mutants lacking carotenoids was characterized for pigment and tocopherol (vitamin E) composition, growth phenotypes under different light conditions, and the molecular basis of their mutant phenotype. The carotenoid-less mutants, or "white" mutants...

Previous work with Flavobacterium strain R1519 has involved the use of inhibitors, especially nicotine, to demonstrate the conversions, in vioo, of lycopene (#,$-carotene) into P-carotene (P,P-carotene) and of lycopene, 8-carotene and rubixanthin (PAcaroten-3-01) into P-cryptoxanthin (D,P-caroten-3-01) and zeaxanthin (D,P-carotene3,3'-diol) (McDermott et al., 1974). The next aim was to develop ...

This paper describes recent biosynthetic and enzymological studies from a number of laboratories and relates them to our current understanding of the pathways of carotenoid formation. A number of problems concerning phytoene biosynthesis and dehydrogenation are discussed and the work of our own laboratory on the biosynthesis of the triterpenoid carotenoids is reviewed.

In vitro studies of the influence of FMC 57020 on terpenoid biosynthesis have shown that this herbicide acts at an early stage. It affects the conversion of isopentenyl pyrophosphate to geranylgeranyl pyrophosphate catalyzed by isopentenyl pyrophosphate isomerase and prenyl transferase. An inhibition of the carotenogenic enzymes phytoene desaturase, ^-carotene desaturase, and lycopene cyclase c...

Assay systems have been developed in order to differentiate between the m odes o f action o f certain bleaching herbicides. These include inhibition o f chlorophyll or carotenoid biosynthesis, and initiation o f pigment degradation. Herbicidal com pounds with phytoene desaturase as their primary target site were investigated in a cell-free carotenogenic system from Aphanocapsa. In a comparative...

Phytoene desaturase (PDS) affects the synthesis of carotenoids. It is a key gene in carotenoids biosynthesis pathway. In order to study function PDS  gene from mango fruits, phytoene dehydrogenase ( ) ‘Guifei’ fruit was obtained with RACE methods. The full-length cDNA sequence 1 820 bp, open reading frame 650 encoding 549 amino acids, molecular weight 61.34 KD, and isoelectric ...

Carotenoids are isoprenyl pigments necessary for protection of the photosynthetic apparatus in a11 green plants. One of the intermediate steps in carotenoid biosynthesis is the conversion of phytoene to {-carotene via two dehydrogenation reactions catalyzed by the enzyme PDS. We have previously cloned cDNAs for this enzyme from soybean (Glycine max; Bartley et al., 1991) and tomato (Lycopersico...