The New Zealand Institute for Plant & Food Research Limited (Plant & Food Research), Palmerston North Research Centre, Palmerston North 4442, New Zealand.
BMC Plant Biol. 2012 Jan 23;12:12. doi: 10.1186/1471-2229-12-12.
The polyphenolic products of the phenylpropanoid pathway, including proanthocyanidins, anthocyanins and flavonols, possess antioxidant properties that may provide health benefits. To investigate the genetic architecture of control of their biosynthesis in apple fruit, various polyphenolic compounds were quantified in progeny from a 'Royal Gala' × 'Braeburn' apple population segregating for antioxidant content, using ultra high performance liquid chromatography of extracts derived from fruit cortex and skin.
Construction of genetic maps for 'Royal Gala' and 'Braeburn' enabled detection of 79 quantitative trait loci (QTL) for content of 17 fruit polyphenolic compounds. Seven QTL clusters were stable across two years of harvest and included QTLs for content of flavanols, flavonols, anthocyanins and hydroxycinnamic acids. Alignment of the parental genetic maps with the apple whole genome sequence in silico enabled screening for co-segregation with the QTLs of a range of candidate genes coding for enzymes in the polyphenolic biosynthetic pathway. This co-location was confirmed by genetic mapping of markers derived from the gene sequences. Leucoanthocyanidin reductase (LAR1) co-located with a QTL cluster for the fruit flavanols catechin, epicatechin, procyanidin dimer and five unknown procyanidin oligomers identified near the top of linkage group (LG) 16, while hydroxy cinnamate/quinate transferase (HCT/HQT) co-located with a QTL for chlorogenic acid concentration mapping near the bottom of LG 17.
We conclude that LAR1 and HCT/HQT are likely to influence the concentration of these compounds in apple fruit and provide useful allele-specific markers for marker assisted selection of trees bearing fruit with healthy attributes.
苯丙烷类途径的多酚产物，包括原花青素、花青素和黄酮醇，具有抗氧化特性，可能对健康有益。为了研究控制苹果果实生物合成的遗传结构，使用从果皮和果肉提取的提取物，通过超高效液相色谱法，对来自‘皇家嘎拉’ב布瑞本’苹果群体的后代中各种多酚化合物进行了定量，该群体在抗氧化含量上存在分离。
‘皇家嘎拉’和‘布瑞本’遗传图谱的构建使我们能够检测到 17 种果实多酚化合物含量的 79 个数量性状位点（QTL）。7 个 QTL 簇在两年的收获中稳定存在，包括类黄酮、黄酮醇、花青素和羟基肉桂酸含量的 QTL。将亲本遗传图谱与苹果全基因组序列进行了比对，在图谱上筛选出与 QTL 共分离的一系列编码多酚生物合成途径中酶的候选基因。通过从基因序列中衍生的标记的遗传作图，证实了这种共定位。类黄酮还原酶（LAR1）与位于连锁群（LG）16 顶部附近的 QTL 簇共定位，该 QTL 簇与果实黄烷醇儿茶素、表儿茶素、原花青素二聚体和 5 种未知原花青素低聚物有关，而羟基肉桂酸/奎宁酸转移酶（HCT/HQT）与位于 LG17 底部附近的绿原酸浓度 QTL 共定位。
我们得出结论，LAR1 和 HCT/HQT 可能影响苹果果实中这些化合物的浓度，并为具有健康属性果实的树木提供有用的等位基因特异性标记，用于辅助选择。
