Biology subjects

Rever, J.

Publications and source records attributed to Rever, J..

3 recordsLinked to original sources

bioRxiv2023

Streamlined regulation of chloroplast development in the liverwort Marchantia polymorpha

Photosynthesis in eukaryotic cells takes place in chloroplasts that develop from undifferentiated plastids in response to light. In angiosperms, after perception of light de-repression allows Elongated Hypocotyl 5 (HY5) transcription factor to initiate photomorphogenesis, and two families of transcription factors known as Golden2-like (GLK) and GATA are considered master regulators of chloroplast development. The MIR171-targeted SCARECROW-LIKE (SCL) GRAS transcription factors also impact on chlorophyll biosynthesis. The extent to which these proteins carry out conserved roles in non-seed plants is not known. Here we report in the model liverwort Marchantia polymorpha that GLK controls chloroplast biogenesis and HY5 shows a small conditional effect on chlorophyll content. In contrast, GATA and SCL have no detectable roles in this fundamental process. ChIP-SEQ and RNA-SEQ revealed that MpGLK regulates many photosynthetic and chloroplast development-related genes, but also has a broader set of targets than previously reported in angiosperms. This implies GLK carries out a conserved role relating to chloroplast biogenesis in land plants but also supports extensive divergence between its targets in M. polymorpha and flowering plants. The data support the hypothesis that regulation of chloroplast biogenesis in M. polymorpha is streamlined compared with angiosperms and allows us to present a core regulatory network for chloroplast biogenesis in land plants.

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↗

bioRxiv2020

Comparative analysis of early divergent land plants and construction of DNA tools for hyper-expression in Marchantia chloroplasts

Chloroplast genes are present at high ploidy in plants, and capable of driving very high levels of gene expression if mRNA production and stability are properly regulated. Marchantia polymorpha is a simple model plant that allows rapid transformation studies, however post-transcriptional regulation in plastids is poorly characterized in this liverwort. We have mapped patterns of transcription in Marchantia chloroplasts. Furthermore, we have obtained and compared sequences from 51 early-divergent plant species, and identified putative sites for pentatricopeptide repeat protein binding that are thought to play important roles in mRNA stabilisation. Candidate binding sites were tested for their ability to confer high levels of reporter gene expression in Marchantia chloroplasts, and levels of protein production and effects on growth were measured in homoplasmic transformed plants. We have produced novel DNA tools for protein hyper-expression in a facile plant system that is a test-bed for chloroplast engineering.

plant biology↗