The control of elevated carotenoid levels in apple flesh

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dc.contributor.advisor Allan, A en
dc.contributor.advisor Dwamena, C en
dc.contributor.advisor Espley, R en Jeon, Subin en 2017-08-02T03:32:56Z en 2017 en
dc.identifier.uri en
dc.description Full text is available to authenticated members of The University of Auckland only. en
dc.description.abstract Carotenoids are yellow, orange and red terpenoids with anti-oxidising properties. In plants, these compounds reduce photooxidative stress, as well as acting as precursors to the abscisic acid and strigolactone biosynthetic pathway. Carotenoids are also associated with the orange and yellow pigmentation of many fruit and flowers. Their potential as health compounds in humans has been implicated in correlations between high dietary carotenoid consumption with reduced development of diseases such as cancer and macular degeneration. Apple is a popular dietary fruit which contains high levels of carotenoids; the majority of which are found in the skin. As the flesh occupies the vast majority of fruit space and weight, increasing carotenoid levels in the flesh would allow for greater nutritional value per fruit. By utilising a population of apples that segregates for high and low carotenoids, the genetic regulation of carotenoids biosynthesis in apple flesh was investigated. QTL analysis was conducted using SNPs identified from 129 individuals from the ‘Aotea’ x ‘M.9’ population, using flesh colour of ripe fruit for phenotypic categorisation. A QTL was identified on LG17 which explained 18.9% and 20.6% of phenotypic variation of fruit across two years. Candidate genes were selected from this region according to their function based on homology, prediction, and published literature. The expression of these genes in fruit flesh was measured across development of carotenoid-high and –low cultivars. A high correlation between the expression of the candidate genes, ESCAROLA (ESC) and MYB-RELATED PROTEIN 305 (MYB305) during early stages of fruit development, and carotenoid concentration at ripe stage was observed. Moreover, early expression of these genes was highly correlated with the expression of lycopene beta-cyclase (LCYβ1). A potential ratelimiting step was identified in the carotenoid biosynthetic pathway, marked by LCYβ1, the expression of which may be regulated by DNA-binding proteins ESCAROLA (ESC) and/or MYB305. The possibility exists that a mechanism to increase fruit flesh carotenoid concentration could result from this knowledge. en
dc.publisher ResearchSpace@Auckland en
dc.relation.ispartof Masters Thesis - University of Auckland en
dc.relation.isreferencedby UoA99264941413402091 en
dc.rights Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher. en
dc.rights Restricted Item. Available to authenticated members of The University of Auckland. en
dc.rights.uri en
dc.rights.uri en
dc.title The control of elevated carotenoid levels in apple flesh en
dc.type Thesis en Biological Sciences en The University of Auckland en Masters en
dc.rights.holder Copyright: The author en
pubs.elements-id 643874 en
pubs.record-created-at-source-date 2017-08-02 en

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