Multiple innovations underpinned branching form diversification in mosses

Abstract

Summary Broad‐scale evolutionary comparisons have shown that branching forms arose by convergence in vascular plants and bryophytes, but the trajectory of branching form diversification in bryophytes is unclear. Mosses are the most species‐rich bryophyte lineage and two sub‐groups are circumscribed by alternative reproductive organ placements. In one, reproductive organs form apically, terminating growth of the primary shoot (gametophore) axis. In the other, reproductive organs develop on very short lateral branches. A switch from apical to lateral reproductive organ development is proposed to have primed branching form diversification.Moss gametophores have modular development and each module develops from a single apical cell. Here we define the architectures of 175 mosses by the number of module classes, branching patterns and the pattern in which similar modules repeat. Using ancestral character state reconstruction we identify two stages of architectural diversification.During a first stage there were sequential changes in the module repetition pattern, reproductive organ position, branching pattern and the number of module classes. During a second stage, vegetative changes occurred independently of reproductive fate.The results pinpoint the nature of developmental change priming branching form diversification in mosses and provide a framework for mechanistic studies of architectural diversification.

Reassessing the role of morphology in bryophyte phylogenetics: Combined data improves phylogenetic inference despite character conflict

“…An alternative to the above strategies is the "integrative approach", whereby morphological characters of interest are mapped onto a molecular phylogeny and either diagnosis or an evolutionary trend is obtained (e.g., Coudert et al, 2017). The main argument for mapping morphology, instead of including it in a simultaneous analysis, relies on that both data sources are independent.…”

Design Principles of Branching Morphogenesis in Filamentous Organisms

“…Importantly, these principles are not restricted to filamentous organisms. Lateral inhibition also governs branching morphogenesis in animal organs or plant root systems [62,68], and apical dominance represents a major control mechanism of the three-dimensional architecture of plant shoot systems [8,69,70,81,125]. Although it is less clear how long-range inhibitory signaling affects morphogenesis in branched animal organs, this raises the question of whether branching may be a 'default mode' and inhibitory cues dominate over branch promoting factors.…”

Quantification of complex modular architecture in plants

“…In fact, quantitative character analyses have already been used successfully to characterize patterns of intraspecific variation in correlation with ecological factors in marine organisms (Kaandorp et al, 2003;Matsumoto, 2004). In this context, other potential uses of MOR-PHOSNAKE include the morphological characterization of mutants in Marchantia polymorpha, which is used in molecular genetics as a model to study the evolution and diversity of regulatory systems in land plants (Ishizaki et al, 2016), and of the development of branching patterns in mosses (Coudert et al, 2017). morphometry; and C.R.…”

“…Morphometrics, the assignment of quantities to biological shapes, is a powerful tool to address taxonomic, evolutionary, functional and developmental questions (Biot et al, 2016;Coudert et al, 2017). Morphometric analysis has undergone a dramatic renaissance in recent years, embracing a range of novel computational and imaging techniques to provide new approaches to phenotypic characterization (Stanton & Reeb, 2016) assisted by the development of a wide array of image analysis softwares (Lobet, 2017).…”