Genome-wide scans reveal genetic architecture of apple flavour volatiles

摘要

Flavour is an important food trait, yet little is known about the genetic architecture and mode of inheritance of apple flavour compounds. The objectives of this study were to: understand the inheritance of flavour volatiles in a clonally replicated germplasm population; unravel correlation networks of volatiles; and to use genome-wide single nucleotide polymorphism (SNP) markers to identify genomic regions that play a role in the expression of flavour volatiles. This analysis revealed that more than half of the 37 volatiles (measured by gas chromatography-mass spectrometry) showed high heritability (h(2) > 0.4), with only a small number (3 of the 37) displaying low heritability (h(2) 0.2). Majority (similar to 85 %) of the significant SNP loci displayed the additive mode of inheritance. Our results supported the roles of MdAAT, MdCXE and MdLOX genes in the expression of apple flavour volatiles. Effect sizes of SNP loci, some of which are associated with multiple compounds, were small (10 %), which is consistent with a polygenic quantitative inheritance model. New genomic locations associated with multiple flavour compounds were found, and some SNPs were associated with both sensory flavour and some flavour volatiles. Simultaneous genome-wide association study for sensory flavour and flavour compounds is recommended for unravelling genetic mechanisms to facilitate marker-assisted breeding for targeted flavours.