Abstract Detail

Stress-tolerant mosses: adaptations to life on the edge, from genes to ecosystems

Mishler, Brent [1], Ekwealor, Jenna T. B. [1], Nosratinia, Sonia [2], Brinda, John [3], Jauregui Lazo, Javier [4], Oliver, Melvin [5].

A Global Phylogeny and Classification of the Dryland Moss Syntrichia.

Syntrichia is a diverse genus of mosses containing about 80 accepted species-level names, occurring worldwide in habitats ranging from late-successional desert biocrusts, to tree trunks and boulders in mid-elevation forests, to mesic alpine meadows. Syntrichia demonstrates an unusual amount of variation in ecology, physiology, and reproductive biology among closely related lineages, so is a good model system for studies of evolutionary ecology. The goal of this study was to understand the higher-level relationships and systematics of the genus. We addressed the following questions: (1) How should Syntrichia be defined as a monophyletic group? (2) What are its closest relatives? (3) What are the major clades within it? (4) What can we infer about its biogeographic history and major trends in morphological evolution and habitat? We took a next-gen genome skimming approach to sequence 339 samples from around the world, chosen to represent the full morphological variation across most of the currently accepted species in the genus. From our de novo genome assemblies for each sample, we selected a small set of nine nuclear loci plus five loci that have had considerable previous use in moss phylogenetic studies: chloroplast rbcL, rps4 + rps4-trnS, trnL-trnF; mitochondrial nad5; and the 18S-26S nuclear rDNA region. We also mined Genbank for these loci for additional Syntrichia exemplars plus outgroups. Phylogenetic analysis proceeded in two steps using an ML approach: (1) we analyzed each of the 14 loci separately to examine individual gene trees; (2) we concatenated the data from 13 of the loci for the combined analyses. The resulting backbone phylogeny was then used for examining biogeography, evolutionary trends in morphology, relating functional traits to habitats, and phylogenetic classification. Results include the discovery of a well-supported Syntrichia clade showing evidence of a Southern Hemisphere origin. Several dispersals north as well as several separate evolutionary transitions from a soil-dwelling habitat to an epiphytic or epilithic one were detected. A diverse, solely Northern Hemisphere clade was discovered that includes both the S. ruralis complex and S. caninervis complex and appears to represent a relatively recent and extensive radiation in ecology and morphology (see following talk by Ekwealor et al). We present a rankless classification under the PhyloCode, and contrast it with a ranked classification our group recently published under the ICN. Based on our backbone phylogeny we apply the name Syntrichia (ranked as a genus under the ICBN) to a large, well-supported clade whose closest relatives are currently placed in the genera Hennediella, Chenia, and Tortula. Some smaller, currently accepted genera proved to be nested in Syntrichia and have been transferred. There are several major clades within Syntrichia that we name, including Borealsyntrichia, the diverse Northern Hemisphere radiation that contains both the S. ruralis and S. caninervis complexes. Species-level classification remains uncertain in many parts of the tree, and will be addressed later, following finer-scale phylogenetic analyses now underway.

1 - University Of California, Berkeley, Department Of Integrative Biology, University And Jepson Herbaria, 1001 Valley Life Sciences Building, # 2465, Berkeley, CA, 94720, United States
2 - University of California, University and Jepson Herbaria, Berkeley, CA, 94720, USA
3 - Missouri Botanical Garden, 4344 Shaw Boulevard, St. Louis, MO, 63110
4 - UC Berkeley, Integrative Biology, 3040 Valley Life Sciences Building #3140, Berkeley, CA, 94720, United States
5 - University of Missouri, Division of Plant Sciences and Interdisciplinary Plant Group, Columbia, MO, 65211, USA

Keywords:
phylogenetics
PhyloCode
mosses
Syntrichia.

Presentation Type: Colloquium Presentations
Number: C5003
Abstract ID:352
Candidate for Awards:None