ORCID Profile
0000-0002-3483-8464
Current Organisations
University of Cambridge
,
University of Oxford
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Publisher: American Chemical Society (ACS)
Date: 07-06-2021
Publisher: Cold Spring Harbor Laboratory
Date: 13-08-2023
DOI: 10.1101/2023.08.11.552970
Abstract: Chloroplast biogenesis is dependent on master regulators from the Golden2-like (GLK) family of transcription factors, but higher order glk mutants contain residual chlorophyll and therefore other proteins must also be involved. Here we identify MYB-related transcription factors as regulators of chloroplast biogenesis in the liverwort Marchantia polymorpha and angiosperm Arabidopsis thaliana . In both species, double mutant alleles in MYB-Related genes show very limited chloroplast development and photosynthesis gene expression is perturbed to a greater extent than mutants of GLK . In M. polymorpha MYB-related genes act upstream of GLK , while in A. thaliana this relationship has been rewired. In both species, genes encoding enzymes of chlorophyll biosynthesis are controlled by both MYB-related and GLK proteins whilst those allowing CO 2 fixation, photorespiration as well as photosystem assembly and repair require the MYB-related proteins. Thus, MYB-related and GLK genes have overlapping as well as distinct targets. We conclude that MYB-related transcription factors act with GLK to orchestrate chloroplast development in land plants.
Publisher: American Chemical Society (ACS)
Date: 12-03-2020
Publisher: Cold Spring Harbor Laboratory
Date: 27-11-2020
DOI: 10.1101/2020.11.27.401802
Abstract: 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- ergent 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.
Publisher: Cold Spring Harbor Laboratory
Date: 10-08-2022
DOI: 10.1101/2022.08.10.503456
Abstract: Land plants comprise two large monophyletic lineages, the vascular plants and the bryophytes, which erged 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.
Publisher: Wiley
Date: 11-04-2023
DOI: 10.1111/TPJ.16161
Abstract: Land plants comprise two large monophyletic lineages, the vascular plants and the bryophytes, which erged 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 optimized 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 dussii , and Phaeoceros carolinianus. The new transformation method is less laborious, faster, and results in the generation of greatly increased numbers of transformants compared with the previous method. We have also developed a new selection marker for transformation. Finally, we report the development of a set of different cellular localization signal peptides for hornworts providing new tools to better understand the hornwort cell biology.
Publisher: Cold Spring Harbor Laboratory
Date: 20-06-2023
DOI: 10.1101/2023.06.17.545419
Abstract: Transcription factors (TFs) are essential for the regulation of gene expression and cell fate determination. Characterising the transcriptional activity of TF genes in space and time is a critical step towards understanding complex biological systems. The vegetative gametophyte meristems of bryophytes share some characteristics with the shoot-apical meristems of flowering plants. However, the identity and expression profiles of TFs associated with gametophyte organization are largely unknown. With only ∼450 TF genes, Marchantia polymorpha is an outstanding model system for plant systems biology. We have generated a near-complete collection of promoter elements derived from Marchantia TF genes. We experimentally tested in planta reporter fusions for all the TF promoters in the collection and systematically analysed expression patterns in Marchantia gemmae. This allowed us to build a map of precise expression domains and identify a unique set of TFs expressed in the stem-cell zone, providing new insight into the dynamic regulation of the gametophytic meristem and its evolution. In addition, we provide an online database of expression patterns for all promoters in the collection. We expect that the promoter elements characterised here will be useful for cell-type specific expression, synthetic biology applications, and functional genomics.
Publisher: Cold Spring Harbor Laboratory
Date: 23-01-2023
DOI: 10.1101/2023.01.23.525199
Abstract: Photosynthesis in eukaryotic cells takes place in specialised plastids. The regulation of plastid development is crucial for multicellular systems such as plants. Two families of transcription factors known as Golden2-like (GLK) and GATA regulate plant chloroplast development, and the miR171-targeted SCARECROW-LIKE (SCL) GRAS transcription factors regulate chlorophyll biosynthesis. The extent to which these proteins carry out conserved roles in non-seed plants such as the liverworts is not known. Here we determine the degree of functional conservation of the GLK, GATA and SCL proteins in controlling chloroplast development in the model liverwort Marchantia polymorpha . Our results indicate that GATA and SCL do not play a detectable role in chloroplast biogenesis but loss of GLK function leads to reduced chloroplast size, underdeveloped thylakoid membranes and lower chlorophyll accumulation. These findings suggest that the functioning of GATA and SCL in chloroplast development either evolved after the ergence of vascular plants from bryophytes, that both roles were secondarily lost in M. polymorpha , or that functional redundancy is masking their roles. In contrast, and consistent with its presence in algae, GLK plays a conserved role in chloroplast biogenesis of liverworts and vascular plants.
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Eftychios Frangedakis.