Genome size and plastid trnK-matK markers give new insights into the evolutionary history of the genus Lavandula L.

Abstract

The genus Lavandula L. consists of 39 species distributed from the North Atlantic Islands, across the Mediterranean Basin to India. We analysed 36 taxa of the genus Lavandula representing two of the three subgenera and six of the eight sections according to the most recent classification (Upson & Andrews 2004). We achieved a phylogenetic reconstruction from partial sequences from plastid trnK and matK genes; the genome size was estimated by flow cytometer measurements. The primary aim was to track phylogenetic patterns through the maternal inherited marker at the sectional level and identify possible genome duplications. The cpDNA tree shows the phylogenetic relationships between subgenus, sections and also elucidates for the first time the relationships between the endemic species of Macaronesia, Morocco and Arabia. The ancestral split between the two subgenera could be explained by dispersal followed by an early vicariance event. The C-value shows genome up-sizing within several phylogenetic clades and geographical areas. An ancestral genome-up sizing is characterized at the node of section Dentatae and Lavandula. The cpDNA tree suggests that the taxa L. angustifolia subsp. pyrenaica (DC.) Guinea and L. stoechas subsp. luiseiri are best treated as a distinct species.

Keywords::

• Lavandula
• phylogeny
• polyploidy
• biogeography
• C-value
• trnK-matK
• plastid marker

Acknowledgements

This work was supported by the Région Rhône-Alpes (France) via funding agency. This work has benefited from the facilities and expertise of the Imagif Cell Biology Unit of the Gif campus (www.imagif.cnrs.fr), which is supported by the Conseil Général de l'Essonne». The authors wish to thank Nicolas Boyer for growing the plants, Sylvie Baudino and Jean-Claude Caissard for helpful comments. The authors thank the anonymous reviewer for constructive comments.

Notes

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