Polymorphism at the ribosomal DNA ITS and its relation to postglacial re-colonization routes of the Perigord truffle Tuber melanosporum
Article first published online: 31 AUG 2004
Volume 164, Issue 2, pages 401–411, November 2004
How to Cite
Murat, C., Díez, J., Luis, P., Delaruelle, C., Dupré, C., Chevalier, G., Bonfante, P. and Martin, F. (2004), Polymorphism at the ribosomal DNA ITS and its relation to postglacial re-colonization routes of the Perigord truffle Tuber melanosporum. New Phytologist, 164: 401–411. doi: 10.1111/j.1469-8137.2004.01189.x
- Issue published online: 31 AUG 2004
- Article first published online: 31 AUG 2004
- Received: 18 March 2004 Accepted: 19 May 2004
- ectomycorrhizal fungi;
- genetic differentiation;
- nested clade analysis;
- ribosomal DNA;
- • Glaciations and postglacial migrations are major factors responsible for the present patterns of genetic variation we see in natural populations in Europe. For ectomycorrhizal fungi, escape from refugia can only follow range expansion by their specific hosts.
- • To infer phylogeographic relationships within Tuber melanosporum, sequences of internal transcribed spacers (ITS) and the 5.8S coding region of the ribosomal DNA repeat were obtained for 188 individuals sampled over the entire distribution of this species in France, and in north-western Italy and north-eastern Spain.
- • Ten distinct ITS haplotypes were distinguished, mapped and treated using F- and NST-statistics and nested clade (NCA) analyses. They showed a significant genetic differentiation between regional populations. NCA revealed a geographical association of ITS haplotypes, an old fragmentation into two major groups of populations, which likely colonized regions on different sides of the French Central Massif.
- • This re-colonization pattern is reminiscent of the one observed for host trees of the Perigord truffle, such as oaks and hazelnut trees. This suggests that host postglacial expansion was one of the major factors that shaped the mycobiont population structure.