Volatile metabolome and allele-specific expression reveal mechanisms of floral scent inheritance in Prunus mume

Abstract

Prunus mume (mei) is a famous traditional Chinese flower, that blossoms in early spring with a pleasant fragrance, which can be used for essential oils and medicinal purposes. However, we know little about the inheritance patterns during mei hybridization, which greatly limits our crossbreeding efforts to cultivate cold-resistant and aromatic varieties. Here, we used headspace solid-phase microextraction combined with gas chromatography-mass spectrometry (HS-SPME-GC-MS) to analyze the volatile compounds of a hybrid variety (XRB) and its parents (DFH × BJYD) at three different stages, respectively. We discovered a number of BJYD-biased genes that are essential for the synthesis and subsequent release of volatile contents of XRB, as well as allele-specific expression patterns, using RNA-seq and genome resequencing. In addition, the association analysis of cis-trans regulation and genetic patterns indicated the importance of trans regulation in forming parental and F₁ differences. This investigation provides valuable insights into the molecular processes controlling the production and emission of XRB volatiles and provides strong support for the breeding of cold-tolerant and aromatic varieties of P. mume.