Abstract Detail

Species delimitation in composite organisms: the value of recognizing species boundaries in lichen symbionts

Leavitt, Steven [1], Nelsen, Matthew [2], Kraichak, Ekaphan [3].

Sharing in the family? Assessing fungal-algal interactions in the lichen-forming family Parmeliaceae.

Microbial symbionts can be instrumental to the ecological and long-term evolutionary success of their hosts. The central role of symbiotic interactions is increasingly recognized across the vast majority of life, and accurately characterizing species-level diversity in symbionts is particularly germane for understanding broad-scale patterns. Relative to other symbiotic systems, lichens provide a relatively simple model for understanding important patterns in species interactions. Although lichens represent an iconic example of symbiosis, interactions among lichen symbionts are often masked by uncertain species boundaries or inability to reliably identify symbionts. The species-rich lichen-forming family Parmeliaceae provides a valuable system for assessing patterns of interactions of lichen symbionts at various scales. While species-level diversity has been well characterized for a number of groups in Parmeliaceae, diversity and interactions of their photosynthetic partner, Trebouxia spp., has received considerable less attention. In this study, we analyzed algal ITS sequence data collected from over 1500 specimens, representing multiple genera in Parmeliaceae (Cetraria, Letharia, Melanelia sensu lato, Oropogon, and Xanthoparmelia). We also included ca. 300 algal sequences from placodioid Lecanora species that often occur in sympatry with the some of the sampled parmelioid genera. Algal sequences were grouped into operational taxonomic units (OTUs) using the Automatic Barcode Gap Detection program and 98% sequence similarity. We explored patterns of symbiont interactions in these lichens based on geographic distribution, ecology, and mycobiont taxonomy. We find high-levels of undescribed diversity in Trebouxia, varying levels of selectivity and specificity, and complex biogeographical patterns. Based on these results, we discuss ways effectively incorporate species discovery and recognition in studies of symbiotic systems. We hope this data helps fill the gap between simply recognizing species boundaries and what it means for understanding symbiotic systems.

1 - The Field Museum, Integrative Research Center, 1400 South Lake Shore Drive, Chicago, IL, 60605, USA
2 - The Field Museum, 1400 S. Lake Shore Drive, Chicago, IL, 60605, USA
3 - Field Museum, Science and Education, 1400 S Lake Shore Drive, Chicago, IL, 60605, USA

Keywords:
symbiosis
Trebouxia
photobiont
mycobiont
interactions
lichens.

Presentation Type: Symposium or Colloquium Presentation
Session: C3
Location: Cottonwoods North/Boise Centre
Date: Wednesday, July 30th, 2014
Time: 10:15 AM
Number: C3001
Abstract ID:184
Candidate for Awards:None