Kumar Satish, Molloy Claire, Hunt Martin, Deng Cecilia Hong, Wiedow Claudia, Andre Christelle, Dare Andrew, McGhie Tony
The New Zealand Institute for Plant and Food Research Limited, Hawke's Bay Research Centre, Havelock North 4130, New Zealand.
The New Zealand Institute for Plant and Food Research Limited, Palmerston North Research Centre, Palmerston North 4410, New Zealand.
Hortic Res. 2022 Sep 26;9:uhac218. doi: 10.1093/hr/uhac218. eCollection 2022.
Understanding the genetic architecture of apple phytochemicals, and their interplay with conventional selection traits, is critical for the development of new apple cultivars with enhanced health benefits. Apple accessions (n = 344) used for this genome-wide association study (GWAS) represented the wide diversity of metabolic profiles in the domesticated and wild genepools. Fruit samples were phenotyped for 34 metabolites, including a stable vitamin C glycoside "ascorbic acid 2-β-glucoside" (AA-2βG), and the accessions were genotyped using the Apple 20 K SNP Array. Several fruit quality traits, including red skin over-colour (OCOL), were also assessed. Wild accessions showed at least 2-fold higher average content of several metabolites (e.g. ascorbic acid, chlorogenic acid, phloridzin, and trilobatin) than accessions. Several new genomic regions and potential candidate genes underpinning the genetic diversity of apple phytochemicals were identified. The percentage of phenotypic variance explained by the best SNP ranged between 3% and 21% for the different metabolites. Novel association signals for OCOL in the syntenic regions on chromosomes 13 and 16 suggested that whole genome duplication has played a role in the evolution of apple red skin colour. Genetic correlations between phytochemicals and sensory traits were moderate. This study will assist in the selection of accessions with specific phytochemical profiles to establish innovative genomics-based breeding strategies for the development of apple cultivars with enhanced nutritional value.
了解苹果植物化学物质的遗传结构及其与传统选择性状的相互作用，对于培育具有更高健康益处的苹果新品种至关重要。用于这项全基因组关联研究（GWAS）的苹果种质（n = 344）代表了驯化和野生基因库中广泛的代谢谱多样性。对果实样本进行了34种代谢物的表型分析，包括一种稳定的维生素C糖苷“抗坏血酸2-β-葡萄糖苷”（AA-2βG），并使用苹果20K SNP芯片对种质进行基因分型。还评估了包括红色果皮上色（OCOL）在内的几个果实品质性状。野生种质的几种代谢物（如抗坏血酸、绿原酸、根皮苷和三叶苷）的平均含量比栽培种质至少高2倍。确定了几个新的基因组区域和潜在的候选基因，这些基因是苹果植物化学物质遗传多样性的基础。不同代谢物中，最佳SNP解释的表型变异百分比在3%至21%之间。在13号和16号染色体的同线性区域中，OCOL的新关联信号表明全基因组复制在苹果红色果皮颜色的进化中发挥了作用。植物化学物质与感官性状之间的遗传相关性中等。这项研究将有助于选择具有特定植物化学特征的种质，以建立基于创新基因组学的育种策略，用于培育具有更高营养价值的苹果品种。
