Project description:In order to elucidate the role of the single Marchantia B-GATA ortholog in response to high light intensities, a transcriptomic analysis of Marchantia polymorpha BoGa, Mpb-gata1 mutants and MpB-GATA1ox under high-ligh stress conditions was performed.
Project description:To evaluate role of PRC2 on transcriptional regulation in bryophytes, we generated loss of function mutants of a Ez homolog in Marchantia polymorpha by CRISPR/Cas9 based mutagenesis. To avoid lethality of PRC2 knockout, we first mutate MpKNOX2 gene then additionally knocked MpEz1 out. Then we performed comparative transcriptome analyses using data obtained from Mpknox2 ez1 and Mpknox2.
Project description:In the present study, Marchantia polymorpha Mppcs loss of function mutants were generated through CRISPR/cas9 mediated genome-editing. To assess whether the knockout of MpPCS gene affects the transcription of M. polymorpha nuclear genes in unstressed condition, the Mppcs-2 knockout mutant and Cam2 wild-type transcriptomes were compared by RNA-Seq.
Project description:The lipid-derived phytohormone jasmonoyl-isoleucine (JA-Ile) regulates plant immunity, growth and development in vascular plants by activating genome-wide transcriptional reprogramming. In Arabidopsis, this is largely orchestrated by the master regulator MYC2 and related transcription factors (TFs). However, the TFs activating this pathway in basal plant lineages are currently unknown. We report the functional conservation of MYC-related TFs between the eudicot Arabidopsis thaliana and the liverwort Marchantia polymorpha, a plant belonging to one of the most basal land-plants lineages. Phylogenetic analysis suggests that MYC function first appeared in charophycean algae, and therefore predates the evolutionary appearance of any other jasmonate pathway component. Marchantia possesses two functionally interchangeable MYC genes, one in females and one in males. Similar to AtMYC2, MpMYCs showed nuclear localization, interaction with JAZ-repressors, and regulation by light. Phenotypic and molecular characterization of loss- or gain-of-function mutants demonstrated that MpMYCs are necessary and sufficient for the activation of the pathway in Marchantia, but unlike their Arabidopsis orthologs, do not regulate fertility. Our results show that despite 450 million years of independent evolution, MYCs are functionally conserved between bryophytes and eudicots. Genetic conservation in one of the most basal lineages suggests that MYC function existed in the common ancestor of land plants and evolved from a pre-existing MYC function in charophycean algae.
Project description:RNA-seq of Marchantia polymorpha Mpb-gata1 mutants was performed in order to investigate their molecular signature of gene expression changes.
Project description:Polycomb repressive complex 1 (PRC1) and PRC2 are chromatin regulators maintaining transcriptional repression by depositing H2A mono-ubiquitination (H2Aub) or H3 lysine 27 tri-methylation (H3K27me3), respectively. While PRC1 is known to be required for transcriptional repression, the contribution of H2Aub in the Polycomb repressive system remains unclear in plants. Here, we directly test the requirement of H2Aub for gene repression in Marchantia polymorpha by generating point mutants in H2A that fail to be ubiquitinated by PRC1. These mutants show reduced H3K27me3 levels on the same target sites as mutants in PRC1 subunits MpBMI1 and the homolog MpBMI1L, revealing that PRC1-catalyzed H2Aub is essential for Polycomb system function. Furthermore, we demonstrate that H2Aub contributes to the PRC1-mediated silencing of genes and transposable elements. Together, our data provide evidence that H2Aub plays indispensable roles in the PRC1-initiated repressive system in Marchantia.
Project description:JAZ genes are negative regulators of jasmonate responses with a dual function as repressors of transcription factors and co-receptors, together with COI1, of the hormone jasmonoyl-isoleucine (JA-Ile). This family has been mainly studied in angiosperms, where high gene redundancy hinders the characterization of a complete depletion of JAZ function. Moreover, the recent discovery that JA-Ile is not the sole COI1/JAZ ligand in land plants, as dn-OPDA is the bioactive ligand in Marchantia polymorpha, underscores the importance of studying JAZ co-receptors in bryophytes. Here we exploited the low gene redundancy of the liverwort Marchantia polymorpha to characterize the function of the single MpJAZ in this early-divergent plant lineage. We demonstrate that MpJAZ is the ortholog of AtJAZ and acts as a repressor of dinor-OPDA responses in Marchantia. Mpjaz mutants show a dwarf phenotype and severe developmental defects related to growth inhibition, consistent with a constitutive activation of the dinor-OPDA pathway and the overaccumulation of both dinor-OPDA and its precursor OPDA. The expression of AtJAZ3 in Mpjaz complements MpJAZ repressor function, indicating that JAZ function is conserved across land plants. However, AtJAZ3 is unable to form co-receptor complexes with MpCOI1 and dn-OPDA, which evidences that the Jas domain, and not only COI1, determines ligand specificity.