Biology subjects

Waller, M.

Publications and source records attributed to Waller, M..

4 recordsLinked to original sources

bioRxiv2024

Molecular underpinnings of hornwort carbon concentrating mechanisms: subcellular localization of putative key molecular components in the model hornwort Anthoceros agrestis.

O_LIBiophysical carbon concentrating mechanisms (CCMs) operating at the single-cell level have evolved independently in eukaryotic algae and a single land plant lineage, hornworts. An essential component for an efficient eukaryotic CCM is a pyrenoid whose biology is well-characterized in the unicellular green alga, Chlamydomonas reinhardtii. By contrast, pyrenoids and CCM are little understood in hornworts. C_LIO_LIHere, we investigate the molecular underpinnings and dynamics of hornwort pyrenoids. We do so by studying the subcellular localization of candidate proteins homologous to essential CCM genes in C. reinhardtii and assessing their mobility kinetics in the hornwort model Anthoceros agrestis. C_LIO_LIWe provide evidence that an EPYC1 analog and the RuBisCO co-localize in the pyrenoid but pyrenoids seem less dynamic in A. agrestis than in C. reinhardtii. We further found that a carbon anhydrase homolog (CAH3) localizes to the pyrenoid, while an LCIB-like homolog is less intimately linked to the pyrenoid than in C. reinhardtii. C_LIO_LIOur results imply that the pyrenoid-based CCM of hornworts is characterized by a mixture of Chlamydomonas-like as well as hornwort-specific features which is in line with its independent evolutionary origin. Using these observations, we provide a first mechanistic model of hornwort CCM. C_LI

plant biology↗

bioRxiv2022

An optimised transformation protocol for Anthoceros agrestis and three more hornwort species

Land plants comprise two large monophyletic lineages, the vascular plants and the bryophytes, which diverged from their most recent common ancestor approximately 480 million years ago. Of the three lineages of bryophytes, only the mosses and the liverworts are systematically investigated, while the hornworts are understudied. Despite their importance for understanding fundamental questions of land plant evolution, they only recently became amenable to experimental investigation, with Anthoceros agrestis being developed as a hornwort model system. Availability of a high quality genome assembly and a recently developed genetic transformation technique makes A. agrestis an attractive model species for hornworts. Here we describe an updated and optimised transformation protocol for A. agrestis which can be successfully used to genetically modify one more strain of A. agrestis and three more hornwort species, Anthoceros punctatus, Leiosporoceros dussi and Phaeoceros carolinianus. The new transformation method is less laborious, faster and results in the generation of greatly increased numbers of transformants compared to the previous method. We have also developed a new selection marker for transformation. Finally, we report the development of a set of different cellular localisation signal peptides for hornworts providing new tools to better understand hornwort cell biology.

plant biology↗

bioRxiv2022

Genome dynamics in mosses: Extensive synteny coexists with a highly dynamic gene space

BackgroundWhile genome evolutionary processes of seed plants are intensively investigated, very little is known about seed-free plants in this respect. Here, we use one of the largest groups of seed-free plants, the mosses, and newly generated chromosome-scale genome assemblies to investigate three poorly known aspects of genome dynamics and their underlying processes in seed-free plants: (i) genome size variation, (ii) genomic collinearity/synteny, and (iii) gene set differentiation. ResultsComparative genomic analyses on the model moss Physcomitrium (Physcomitrella) patens and two genomes of Funaria hygrometrica reveal that, like in seed plants, genome size change (approx. 140 Mbp) is primarily due to transposable element expansion/contraction. Despite 60 million years of divergence, the genomes of P. patens and F. hygrometrica show remarkable chromosomal stability with the majority of homologous genes located in conserved collinear blocks. In addition, both genomes contain a relatively large set of lineage-specific genes with no detectible homologs in the other species genome, suggesting a highly dynamic gene space fueled by the process of de novo gene birth and loss rather than by gene family diversification/duplication. ConclusionsThese, combined with previous observations suggest that genome dynamics in mosses involves the coexistence of a collinear homologous and a highly dynamic species-specific gene sets. Besides its significance for understanding genome evolution, the presented chromosome-scale genome assemblies will provide a foundation for comparative genomic and functional studies in the Funariaceae, a family holding historical and contemporary model taxa in the evolutionary biology of mosses.

genomics↗

bioRxiv2021

A simple Agrobacterium-mediated stable transformation technique for the hornwort model Anthoceros agrestis

We have developed a simple Agrobacterium-mediated method for the stable transformation of the hornwort Anthoceros agrestis, the fifth bryophyte species for which a genetic manipulation technique becomes available. High transformation efficiency was achieved by using thallus tissue grown under low-light conditions. We generated a total of 216 transgenic A. agrestis lines expressing the {beta}-Glucuronidase (GUS), cyan, green, and yellow fluorescent proteins under the control of the CaMV 35S promoter and several endogenous promoters. Nuclear and plasma membrane localization with multiple color fluorescent proteins was also confirmed. The transformation technique described here should pave the way for detailed molecular and genetic studies of hornwort biology, providing much needed insight into the molecular mechanisms underlying symbiosis, carbon-concentrating mechanism, RNA editing, and land plant evolution in general.

plant biology↗