Figure 1.

The native BKT of C. reinhardtii and its potential role in astaxanthin production. (a) Schematic of the carotenoid pathway towards astaxanthin biosynthesis, according to Misawa et al. (1995) and Alvarez et al. (2006). Only major carotenoids are indicated. Name of enzymes are reported. BKT, carotene β‐ketolase; CHYB, carotene β‐hydroxylase; CHYE, carotene ε‐hydroxylase; CRTISO, carotenoid isomerase; LCYB, lycopene β‐cyclase; LCYE, lycopene ε‐cyclase; NSY, neoxanthin synthase; PDS, phytoene desaturase; VDE, violaxanthin de‐epoxidase; ZDS, ζ‐carotene desaturase; ZEP, zeaxanthin epoxidase. (b) Gene expression level of CrBKT native gene compared to other carotenoid biosynthetic genes. Expression levels in different conditions were retrieved from ChlamyNET database http://viridiplantae.ibvf.csic.es/ChlamyNet/. (c) Protein sequence alignment of BKT from different algae. BKT protein sequences from Chlamydomonas reinhardtii, Haematococcus lacustris and Chlamydomonas zofingensis were aligned by multiple alignment highlighting the long C‐terminal amino acid extension of CrBKT. Colour code is on the base of consensus.