A further outcome of the Liverwort Tree of Life project is the study by Laenen et al., which was released today on-line. The study is entitled “Increased diversification rates follow shifts to bisexuality in liverworts” and is published in the  New Phytologist. [pdf]

 

Abstract reads: Shifts in sexual systems are one of the key drivers of species diversification. In contrast to angiosperms, unisexuality prevails in bryophytes. Here, we test the hypotheses that bisexuality evolved from an ancestral unisexual condition and is a key innovation in liverworts. We investigate whether shifts in sexual systems influence diversification using hidden state speciation and extinction analysis (HiSSE). This new method compares the effects of the variable of interest to the best-fitting latent variable, yielding robust and conservative tests. We find that the transitions in sexual systems are significantly biased toward unisexuality, even though bisexuality is coupled with increased diversification. Sexual systems are strongly conserved deep within the liverwort tree but become much more labile toward the present. Bisexuality appears to be a key innovation in liverworts. Its effects on diversification are presumably mediated by the interplay of high fertilization rates, massive spore production and long-distance dispersal, which may separately or together have facilitated liverwort speciation, suppressed their extinction, or both. Importantly, shifts in liverwort sexual systems have the opposite effect when compared to angiosperms, leading to contrasting diversification patterns between the two groups. The high prevalence of unisexuality among liverworts suggests, however, a strong selection for sexual dimorphism.

A new article about the work Lily and Bernard have been involved in in the Cape Horn Biosphere Reserve: Rozzi R., L. Lewis, F. Massardo & B. Goffinet. 2015. Luupidega ökoturism samblafloora väärtustamiseks: ülekutse Lõunast. [Ecotourism with a hand-lens to appreciate the bryoflora: an invitation from the South.] Samblasõber 18: 2–13. http://www.botany.ut.ee/bruoloogia/Rozzi.etal.SS.2015.pdf

After almost six years in EEB and our lab, Lily packed her books, cleaned her desk and moved to Chile, to  assist with the Tracing Darwin’s Path course and work with Ricardo Rozzi until April. Happy travels.

The early on-line version of the publication in Plant Biology:

Magdy M., O. Werner, S.F. McDaniel, B. Goffinet & R.M. Ros. 2015. A genomic scanning using AFLP to detect loci under selection in Funaria hygrometrica Hedw. along a climatic gradient in the Sierra Nevada mountains (Spain). Plant Biology (in press). doi:10.1111/plb.12381

is now available.

The abstract reads:

The common cord moss Funaria hygrometrica has a worldwide distribution and thrives in a wide variety of environments. Here, we studied the genetic diversity in F. hygrometrica along an abiotic gradient in the Mediterranean high mountain of Sierra Nevada (Spain) using a genome scan method. Eighty-four samples from 17 loca- tions from 24 to 2700 m were fingerprinted based on their amplified fragment length polymorphism (AFLP) banding pattern. Using PCA and Bayesian inference we found that the genetic diversity was structured in three or four clusters, respectively. Using a genome scan method we identified 13 outlier loci, which showed a signature of posi- tive selection. Partial Mantel tests were performed between the Euclidean distance matrices of geographic and climatic variables, versus the pair-wise genetic distance of the AFLP dataset and AFLP-positive outliers dataset. AFLP-positive outlier data were significantly correlated with the gradient of the climatic variables, suggesting adaptive variation among populations of F. hygrometrica along the Sierra Nevada Mountains. We highlight the additional analyses necessary to identify the nature of these loci, and their biological role in the adaptation process.

Isabel Draper, a visting professor from the Universidad de Madrid visited our lab, working on identifying new nuclear makers for phylogenetic reconstructions, from genomic data. She succeeded and is now heading home with primers, DNA and sequences….  Bon voyage.

Jessica Budke, a lab alum and postdoc on the Funariaceae project co-authored a study on the chemistry of the cuticle covering the moss calyptra, entitled:

“Identification of β-hydroxy fatty acid esters and primary, secondary-alkanediol esters in cuticular waxes of the moss Funaria hygrometrica” and published in Phytochemistry.

Abstrat: The plant cuticle, a multi-layered membrane that covers plant aerial surfaces to prevent desiccation, consists of the structural polymer cutin and surface-sealing waxes. Cuticular waxes are complex mixtures of ubiquitous, typically monofunctional fatty acid derivatives and taxon-specific, frequently bifunctional specialty compounds. To further our understanding of the chemical diversity of specialty compounds, the waxes on the aerial structures of the leafy gametophyte, sporophyte capsule, and calyptra of the moss Funaria hygrometrica were surveyed. Respective moss surfaces were extracted, and resulting lipid mixtures were analyzed by gas chromatography–mass spectrometry (GC–MS). The extracts contained ubiquitous wax compound classes along with two prominent, unidentified classes of compounds that exhibited some characteristics of bifunctional structures. Microscale transformations led to derivatives with characteristic MS fragmentation patterns suggesting possible structures for these compounds. To confirm the tentative structure assignments, one compound in each of the suspected homologous series was synthesized. Based on GC–MS comparison with the authentic standards, the first series of compounds was identified as containing esters formed by β-hydroxy fatty acids and wax alcohols, with ester chain lengths varying from C42 to C50 and the most prominent homolog being C46. The second series consisted of fatty acid esters of 1,7-alkanediols, linked via the primary hydroxyl group, with ester chain lengths C40–C52 also dominated by the C46 homolog. The β-hydroxy acid esters were restricted to the sporophyte capsule, and the diol esters to the leafy gametophyte and calyptra. Based on their homolog and isomer distributions, and the presence of free 1,7-triacontanediol, possible biosynthetic reactions leading to these compounds are discussed.

Laenen, B. A. Machac, S. R. Gradstein, B. Shaw, J. Patiño, A. Désamoré, B. Goffinet, C. J. Cox, A. Vanderpoorten & J. Shaw. Geographic range in liverworts: does sex really matter? Journal of Biogeography. in press. pdf

Abstract: Why some species exhibit larger geographical ranges than others remains a fundamental, but largely unanswered, question in ecology and biogeography. In plants, a relationship between range size and mating system was proposed over a century ago and subsequently formalized in Baker’s Law. Here, we take advantage of the extensive variation in sexual systems of liverworts to test the hypothesis that dioecious species compensate for limited fertilization by producing vegetative propagules more commonly than monoecious species. As spores are assumed to contribute to random long-distance dispersal, whereas vegetative propagules contribute to colony maintenance and frequent short-distance dispersal, we further test the hypothesis that monoecious species exhibit larger geographical ranges than dioecious ones.

A phylogenetic assessment of the genus Aptychella has been published (link):

Akiyama, H. A. Schäfer-Verwimp, N. Printarakul, M. Suleiman, B.C. Tan, B. Goffinet & F. Müller. 2015. Phylogenetic study of the genus Aptychella (Pylaisiadelphaceae, Musci). The Bryologist 118: 273–283.

The abstract reads: The relationships among species of the epiphytic genus Aptychella (Broth.) Herzog and Clastobryopsis M. Fleisch. were inferred based on phylogenetic analyses of plastid (rpl16, rps4, and trnL-F) and mitochondrial (nad5) gene sequences as well as morphological features. One of the Asian members, Aptychella robusta (M. Fleisch.) M. Fleisch., exhibits much genetic variation and differentiation among populations, which may reflect the presence of cryptic species. The distinctiveness of Asian members characterized by unicostate leaves, A. brevinervis (M. Fleisch.) M. Fleisch., A. pseudobrevinervis H. Akiyama and A. oblongifolia H. Akiyama, are confirmed. On the contrary, Aptychella proligera, the sole member of the genus known from South and Central America, is shown to have a close relationship to the A. brevinervis complex and preserves low genetic variation among samples collected from geographically remote localities. This lack of variation might be caused by a recent immigration from Asian populations. The Asiatic genus Clastobryopsis is treated as a synonym of Aptychella based on the present phylogenetic analyses. One new combination is proposed—Aptychella imbricata (H. Akiyama et al.) H. Akiyama comb. nov.

Collaborators on the NSF project focus on the Sticta phylogeny met in Storrs from Sept. 14-18. Reports included an update on new species discovered in Madagascar, China, Colombia and other parts of the world, as well as mt genome structure in these lichenized fungi and their associated cyanobacteria.

 

Martha assembled and annotated the mt genome of Oxystegus tenuirostris, which is now published:

Alonso, M., R. Medina, M.J. Cano, J.A. Jiménez & B. Goffinet. (in press). The complete mitochondrial genome of the moss Oxystegus tenuirostris (Hook. & Taylor) A.J.E. (Pottiaceae, Bryophyta). Mitochondrial DNA (Mitogenome announcement).