Identification of QTL controlling the ratio of linalool to linalyl acetate in the flowers of Lavandula angustifolia Mill var. Hemus

Abstract

The content of linalyl acetate and the ratio of linalool to linalyl acetate (L/LA ratio) are one of the important parameters that determine the quality of lavender oil. The characterization of a segregating population derived from a self-pollinated Lavandula angustifolia var. Hemus resulted in the identification of a single quantitative trait locus controlling the L/LA ratio (L/LA-QTL) and located on chromosome 8 of the lavender reference genome. The L/LA data analysis demonstrated that plants homozygous for one of the L/LA-QTL alleles had significantly higher linalool content, lower linalyl acetate content and higher L/LA ratio, than the plants which were either heterozygous or homozygous for the other allele. No significant difference was observed for the sum of linalool and linalyl acetate content among these three groups of plants, suggesting that the identified L/LA-QTL is related to an enzyme conversion of linalool to linalyl acetate. The BLAST search revealed that the L/LA-QTL region included a sequence of the LiAAT4 gene of monoterpene acetyltransferase, considered as a candidate gene for the L/LA-QTL locus. Sequence analysis of the LiAAT4 gene of var. Hemus revealed the presence of two alleles differing in two nucleotides and predicted amino acid substitutions. The comparison of the allele configurations of SSR, SRAP and LiAAT4 loci and the L/LA ratio of plants showing recombination in the L/LA-QTL region provided further support that LiAAT4 is a candidate gene underlying the identified L/LA-QTL and controlling the L/LA ratio. The application of molecular markers for the identified L/LA-QTL is discussed.

Keywords:

• Lavender
• Lavandula angustifolia Mill
• linalool to linalyl acetate ratio
• QTL
• SSR markers
• SRAP markers

Acknowledgment

The authors would like to thank Rumyana Velcheva (AgroBioInstitute, Sofia, Bulgaria) for the excellent technical assistance.

Authors’ contributions

Conceptualization, I.A. and K.R.; Methodology, I.A., K.R., M.R. and P.V.; Software, K.R., P.V. and I.A.; Investigation, P.V.; Resources, I.A.; Writing, I.A. and K.R.; Funding Acquisition, I.A. All authors have read and approved the final version of the article.

Disclosure statement

No potential conflict of interest was reported by the authors.

Data availability statement

All data included in this study are available from the corresponding author [I.A.] upon request.

Additional information

Funding

This work was supported by the Bulgarian National Science Fund under Grant KP-06-N56/2, as well as by the Operational Program Science and Education for Smart Growth 2014–2020, co-financed by the European Union through the European Structural and Investment Funds, Grant BG05M2OP001-1.002-0012 Sustainable utilization of bio-resources and waste of medicinal and aromatic plants for innovative bioactive products.