Profiling of Volatile Compounds and Associated Gene Expression in Two Anthurium Cultivars and Their F1 Hybrid Progenies

Abstract

Anthurium is an important ornamental crop in the world market and its floral scent can enhance its ornamental value. To date, studies of the components and formation mechanism of the floral scent of Anthurium are relatively few. In this study, the scent profiles of two Anthurium varieties were measured by gas chromatograph-mass spectrometer (GC-MS). There were 32 volatile organic compounds (VOCs) identified in Anthurium 'Mystral', and the most abundant compound was eucalyptol (57.5%). Extremely small amounts of VOCs were detected in Anthurium 'Alabama'. Compared with A. 'Alabama', most genes related to floral scent synthesis exhibited a higher expression in A.'Mystral', including AaDXS, AaDXR, AaMDS, AaHDS, AaTPS, AaDAHPS, AaADT2, AaPAL1, and AaPAL2. In order to produce new varieties of Anthurium with fragrance, 454 progenies of two crossbred combinations of A. 'Mystral' and A. 'Alabama' were obtained. Four F1 generation plants with different floral scent intensities were selected for further study. The major components of floral scent in the progenies were similar to that of the parental A.'Mystral' plant. The expression patterns of genes related to floral scent synthesis were consistent with the relative contents of different types of VOCs. This study revealed the profiles of volatile compounds and associated gene expression in two Anthurium cultivars and their F1 hybrids, which provided a basis for the floral scent inheritance of Anthurium andraeanum.

Keywords: Anthurium andraeanum; VOCs; floral scent; gene expression; hybrid progenies.

Figure 1

Overview of the main volatile organic compounds’ biosynthetic pathways: terpenoids (pink), phenylpropanoids/benzenoids (blue), and fatty acid derivatives (yellow).In this study, the components of floral scents and the expression levels of floral scent biosynthesis-related genes were identified in A. ‘Mystral’ (with strong fragrance) and A. ‘Alabama’ (with no fragrance). In addition, the floral scent biosynthesis characteristics were further explored in the F1 hybrids of A. ‘Mystral’ and A. ‘Alabama’, including the presence or absence of floral scent, the types and contents of VOCs, and the expression patterns of VOC synthesis-related genes. In this study, the hybrid progenies of Anthurium andraeanum with aroma and Anthurium andraeanum without aroma were established and the inheritance of aroma was preliminarily explored, providing a theoretical basis for the inheritance of floral scent in A. andraeanum and laying a foundation for the creation of new A. andraeanum varieties with fragrance.

Figure 2

Phenotype of A. ‘Alabama’ and A. ‘Mystral’. S1, spathe folding stage; S2, pistillate emerge stage; S3, spadix fully extended stage.

Figure 3

The relative expression levels of VOC biosynthesis-related genes in the inflorescences of A. ’Mystral’ and A. ‘Alabama’. (a) The relative expression levels of monoterpene biosynthesis-related genes; (b) The relative expression levels of key genes in the phenylpropane biosynthesis or shikimate pathways. TS, the top part of the inflorescences; MS, the middle part of the inflorescences; BS, the base part of the inflorescences.

Figure 4

The relative expression levels of VOC biosynthesis-related genes in the top part of the inflorescences of progenies and A. ‘Mystral’. (a) The relative expression levels of monoterpene biosynthesis-related genes; (b) The relative expression levels of key genes in phenylpropane biosynthesis or shikimate pathways. The relative bar color intensities represent the total amount of VOCs.