Perspectives on ICOM 6 “beyond the roots”

Abstract

From August 9 to 14, 2009, the Sixth International Conference on mycorrhizas brought together 290 participants from 41 countries to learn first-hand the latest information on mycorrhizal research. All activities and the housing for most participants were centered at the Ouro Minas Palace Hotel in the city of Belo Horizonte, Brazil. ICOM 6 was organized by the Microbiology Department of the Federal University of Vicosa and the International Mycorrhiza Society (IMS). The conference was organized around 11 topic areas covered in workshops, symposia, and poster sessions held on each of 4 days which gave time for informal debate and discussion outside formal sessions. One day midconference was devoted to tours to various scenic areas in the state of Minas Gerais. Topics were genome structure and evolution, cell biology and development, signal perception and metabolism, population structure, community diversity, plant–fungal community interactions, nutritional interactions, mycorrhizosphere interactions, stress tolerance, mycoheterotrophic interactions, and systematics of glomeromycetes. Of the presentations, 72 were oral and 218 were posters. Almost 72% of these concerned arbuscular mycorrhizal (AM) fungi, 25% involved ectomycorrhizal (ECM) fungi, and nearly 3% reported on coevolution, conservation potential, and diversity of fungi forming symbiosis with orchids. In this report, we can highlight the content of only a few of the excellent presentations and posters at ICOM 6, and we apologize to colleagues whose interesting work is not mentioned. Jose Siqueira spoke at the opening ceremony and discussed the three decades of research on mycorrhizal symbioses conducted in Brazil. It was clear from his talk that the projects are as eclectic as the habitats spanning this large country. Even though some work done in the tropics was reported, considerable potential exists to accomplish much more in such an expansive natural laboratory. A stimulating keynote lecture started each day. George Kowalchuk provided a broad overview of the application of genomics and metagenomics to elucidating community dynamics and processes occurring in soil microbes. All other keynote talks focused on AM fungi. Sally Smith provided insights into new ways of interpreting positive and negative consequences of phosphorus responses in mycorrhizal plants based on partitioning of P transfer pathways in the plant versus fungal symbiont. Paola Bonfante discussed recent developments in fungus–plant interactions at the cellular level, some of which were depicted in a breathtaking video. This and other reports provide striking evidence of the depth and breadth of AM fungus–plant coevolution. Lastly, Peter Young discussed progress on the Glomus intraradices genome project. While problems and challenges have plagued this project, valuable information is being obtained. Most notably, genome size is considerably larger than previously estimated, as is gene variability and organization. This species is a model organism, justified in part because of its ubiquity worldwide. The diversity of haplotypes, the ability to anastomose among populations, suggestions of putative recombination, and other interactions likely will not translate to other lineages, even within J. Morton Plant and Soil Sciences, West Virginia University, Morgantown, WV 26506-6108, USA