Progress and Prospects for the Ecological Genetics of Mycoheterotrophs

Mycoheterotrophic plants provide fascinating evolutionary narratives. Examples include convergent evolution of traits such as miniscule seeds, shortened and thickened roots, narrow mycorrhizal speci fi city, and self-fertilization (Leake 1994 ) . Another example is provided by the patterns of decay of the photosynthetic machinery (DePamphilis and Palmer 1990 ; Barrett and Freudenstein 2008 ; Delannoy et al. 2011 ; Logacheva et al. 2011 ) . Finally, the dynamics of specialization and host-jumps among various clades of fungal hosts (Taylor et al. 2004 ; Kennedy et al. 2011 ) offer compelling cases for comparison with more “main-stream” parasites, such as lice (Hafner and Page 1995 ) , phytophagous insects (Hawthorne and Via 2001 ) , or rust fungi (Jarosz and Burdon 1991 ) . Another interesting feature of mycoheterotrophs, which is perhaps less often considered, is that multiple traits, including most of those mentioned above, appear to be evolving rapidly across numerous independent lineages. For example, from the limited sampling available at present, it appears that sister species of mycoheterotrophic plants always target different fungal clades (Taylor and Bruns 1999 ; Bidartondo and Bruns 2001, 2002 ; Kennedy et al. 2011 ) . This phenomenon is too widespread to be merely coincidence. But we are currently without any clear understandings of the evolutionary dynamics and selective pressures that underlie this phenomenon. Investigation of selective pressures and rapidly evolving traits falls principally under the purview of population genetics, quantitative genetics, genomics, and molecular evolution. When applied to ecological questions, these fi elds form the basis for ecological genetics, the subject of this review. Ecological genetics of mycoheterotrophic plants is only in its infancy, hence in this review we suggest some ideas about ways in which ecological genetics might enlighten the fi eld of mycoheterotrophic plant research going forward. We also present case studies of several fully mycoheterotrophic D. L. Taylor (*) • S. E. Hopkins Institute of Arctic Biology, University of Alaska Fairbanks , 311 Irving I Building , Fairbanks , AK 99775 , USA e-mail: [email protected]