Optimising ketocarotenoid production in potato tubers: Effect of genetic background, transgene combinations and environment

• Published in: Plant science (Limerick) 2015-05, Vol.234, p.27-37
• Main Authors: Campbell, Raymond, Morris, Wayne L., Mortimer, Cara L., Misawa, Norihiko, Ducreux, Laurence J.M., Morris, Jenny A., Hedley, Pete E., Fraser, Paul D., Taylor, Mark A.
• Format: Article
• Language: English
• Subjects: Astaxanthin; Carotenoid; Carotenoids - chemistry; Carotenoids - metabolism; Environment; Genetic Background; Ketocarotenoid; Metabolic Engineering; Metabolome; Microarray; Plant Tubers - chemistry; Plant Tubers - genetics; Plant Tubers - metabolism; Plants, Genetically Modified; Potato; Solanum tuberosum - chemistry; Solanum tuberosum - genetics; Solanum tuberosum - metabolism; Transcriptome; Transgenes; Xanthophylls - chemistry; Xanthophylls - metabolism
• ISSN: 0168-9452; 1873-2259
• DOI: 10.1016/j.plantsci.2015.01.014

•Potato tubers have been engineered to accumulation ketocarotenoids.•The level of astaxanthin achieved is nutritionally significant.•Combinations of transgenes have been optimised.•The choice of parental material for transformation was shown to be critical.•A strong effect of environment on tuber carotenoid profile was demonstrated. Astaxanthin is a high value carotenoid produced by some bacteria, a few green algae, several fungi but only a limited number of plants from the genus Adonis. Astaxanthin has been industrially exploited as a feed supplement in poultry farming and aquaculture. Consumption of ketocarotenoids, most notably astaxanthin, is also increasingly associated with a wide range of health benefits, as demonstrated in numerous clinical studies. Currently astaxanthin is produced commercially by chemical synthesis or from algal production systems. Several studies have used a metabolic engineering approach to produce astaxanthin in transgenic plants. Previous attempts to produce transgenic potato tubers biofortified with astaxanthin have met with limited success. In this study we have investigated approaches to optimising tuber astaxanthin content. It is demonstrated that the selection of appropriate parental genotype for transgenic approaches and stacking carotenoid biosynthetic pathway genes with the cauliflower Or gene result in enhanced astaxanthin content, to give six-fold higher tuber astaxanthin content than has been achieved previously. Additionally we demonstrate the effects of growth environment on tuber carotenoid content in both wild type and astaxanthin-producing transgenic lines and describe the associated transcriptome and metabolome restructuring.