Product stability and sequestration mechanisms in Solanum tuberosum engineered to biosynthesize high value ketocarotenoids

• DOI: 10.1111/pbi.12365
• Publication Date: 2015-04-02T22:06:30Z
• Authors: Cara L. Mortimer; Norihiko Misawa; Laurence Ducreux; Raymond Campbell; Peter M. Bramley; Mark Taylor; Paul D. Fraser
• Keywords: Solanum tuberosum; Secondary metabolite

Summary To produce commercially valuable ketocarotenoids in Solanum tuberosum , the 4, 4′ β‐oxygenase ( crtW ) and 3, 3′ β‐hydroxylase (c rtZ genes from Brevundimonas spp. have been expressed plant host under constitutive transcriptional control. The CRTW CRTZ enzymes are capable of modifying endogenous carotenoids to form a range hydroxylated ketolated derivatives. (cv. Désirée) produced significant levels nonendogenous carotenoid products all tissues, but at apparent expense economically critical metabolite, starch. Carotenoid increased both wild‐type transgenic tubers following cold storage; however, stability during heat processing varied between compounds. Subcellular fractionation leaf tissues revealed presence thylakoid membranes, not predominantly photosynthetic complexes. A dramatic increase content plastoglobuli was determined. These findings were corroborated by microscopic analysis chloroplasts. In tuber esterified carotenoids, representing 13% total pigment found extracts, sequestered plastoglobuli. tubers, this proportion 45%, with place Conversely, nonesterified associated amyloplast membranes starch granules.