Sex-Specific Fungal Communities of the Dioicous Moss Ceratodon purpureus

Abstract

Mosses display a number of hallmark life history traits that influence their ecology at the population and community level. The long lived separation of sexes observed in the haploid gametophyte (dioicy) is one such feature of particular importance, as it is observed in the majority of bryophytes and creates intraspecific specialization of male and female individuals.The prevalence of sexually dimorphic mosses raises the possibility of sex-specific interactions with fungi as observed in some vascular plants. Here I investigated how moss sex shapes fungal communities associated with gametophytic tissues of the ubiquitous moss, Ceratodon purpureus. Using greenhouse populations of C. purpureus grown in a common garden, I examined fungal community structure and overall abundance of fungal biomass associated with male and female individuals from multiple populations. I hypothesized that individual mosses would harbor unique fungal communities based on their sex, and that overall fungal biomass associated with host tissues would differ significantly due to differences in morphological and physiological characteristics between the sexes. I found that fungal community composition and overall abundance (i.e. biomass) differ between male and female individuals of C. purpureus, and that sex-specific patterns are retained across individuals from three different populations. This work provides a first glance at how genetically based sexual systems in early land plants influence affiliated fungal community composition.ii Acknowledgments

Microarthropod contributions to fitness variation in the common mossCeratodon purpureus

“…Additionally, our results suggest that natural populations of C. purpureus which lack commensal arthropods may be sperm-limited, a result previously reported in other moss species [52]. Currently, it is unclear what reward, if any, springtails gain from the behavior, although a moss could provide food sources such as secreted sugars and fatty acids [25,53,54], bacteria or fungi [55], or the moss itself [56].…”

Sex-specific morphological and physiological differences in the moss Ceratodon purpureus (Dicranales)

“…In mosses, thicker and larger leaves may allow females greater protection against fungal pathogens, which occur at high densities in moss communities (Davey and Currah, 2006;Davey et al, 2013). Indeed, males from these same study populations, with thinner leaves, were recently found to have higher fungal biomass and richness than females (Balkan, 2016). In fact, if the higher photochemical values in females allow for greater overall net assimilation, this could provide the resources needed for fungal chemical defences and/or volatile compounds that have been hypothesized as contributing to an early 'plant pollinator'-like syndrome in C. purpureus (Cronberg et al, 2006;Cronberg, 2012;Rosenstiel et al, 2012).…”

“…However, in bryophytes, we know little about the breadth of between-sex diversity in morphological traits (Shaw and Beer, 1999;McLetchie and Puterbaugh, 2000;Horsley et al, 2011) or physiological traits (Stark et al, 2005;McLetchie and Stark, 2006;Groen et al, 2010), and comparatively little emphasis has been placed on understanding the underlying sex-specific physiological differences in dioecious mosses at a finer scale and their contributions to sexual dimorphisms (Stark et al, 2009). Developing this sex-specific framework is also important for understanding how moss-dominated ecosystems (the bryosphere), which occur on every continent and dominate major portions of the earth's surface, shape the function and diversity of heterotrophic communities (Lindo and Gonzalez, 2010;Balkan, 2016) and consequently nutrient cycling (Cornelissen et al, 2007;Turetsky et al, 2012;Delgado-Baquerizo et al, 2016) in ecosystems.…”

Isoprene Emission in Polytrichaceae Mosses

“…Other local influences exerted by moss emitted BVOC's may include sex-specific volatile compounds that influence microarthropods mediated fertilization in mosses(Rosenstiel et al 2012). Further, there are sex-specific fungal communities that affect their ecology(Sharkey et al 2001;Devika et al 2012;Kandi et al 2015, Balkan 2016.Mosses can influence nearby atmospheric process by emitting isoprene which is reduced by hydroxyl radical (OH) into water droplet nucleation. Secondary Organic Aerosol (SOA) acts as a local form of cloud or fog seeding allowing plants to exert influence on the atmospheric hydrological conditions of its local microclimate.…”