Redox buffering and HO orchestrate the vegetative development of Marchantia polymorpha.

Redox processes and reactive oxygen species (ROS) signaling play not only a crucial role in stress responses but also in angiosperm development. However, the specific mechanisms by which redox homeostasis regulates meristems and growth in non-vascular plants remain poorly understood. Here, we demonstrate the applicability of the roGFP2-hGrx1 and HyPer7 redox-biosensors for imaging dynamic glutathione (GSH) and HO redox states in the liverwort Marchantia polymorpha.

Sexual reproduction in land plants: an evolutionary perspective.

We link key aspects of land plant reproductive evolution and detail how successive molecular changes leading to novel tissues and organs require co-evolution of communication systems between tissues. The transition of water-dependent reproduction of algae to mechanisms with very limited water dependence in many land plant lineages allowed plants to colonize diverse terrestrial environments, leading to the vast variety of extant plant species. The emergence of modified cell types, novel tissues, and organs enabled this transition; their origin is associated with the co-evolution of novel or adapted molecular communication systems and gene regulatory networks.

Identification and characterization of DICER-LIKE genes and their roles in Marchantia polymorpha development and salt stress response.

DICER-LIKE (DCL) proteins play a central role in plant small RNA (sRNA) biogenesis. The genome of the early land plant Marchantia polymorpha encodes four DCL proteins: MpDCL1a, MpDCL1b, MpDCL3, and MpDCL4. While MpDCL1a, MpDCL3 and MpDCL4 show high similarities to their orthologs in Physcomitrium patens and Arabidopsis thaliana, MpDCL1b shares only a limited homology with PpDCL1b, but it is very similar, in terms of functional domains, to orthologs in other moss and fern species.

Contrasting and conserved roles of NPR pathways in diverged land plant lineages.

The NPR proteins function as salicylic acid (SA) receptors in Arabidopsis thaliana. AtNPR1 plays a central role in SA-induced transcriptional reprogramming whereby positively regulates SA-mediated defense. NPRs are found in the genomes of nearly all land plants.

Divergent evolution of the alcohol-forming pathway of wax biosynthesis among bryophytes.

The plant cuticle is a hydrophobic barrier, which seals the epidermal surface of most aboveground organs. While the cuticle biosynthesis of angiosperms has been intensively studied, knowledge about its existence and composition in nonvascular plants is scarce. Here, we identified and characterized homologs of Arabidopsis thaliana fatty acyl-CoA reductase (FAR) ECERIFERUM 4 (AtCER4) and bifunctional wax ester synthase/acyl-CoA:diacylglycerol acyltransferase 1 (AtWSD1) in the liverwort Marchantia polymorpha (MpFAR2 and MpWSD1) and the moss Physcomitrium patens (PpFAR2A, PpFAR2B, and PpWSD1).

MpTGA, together with MpNPR, regulates sexual reproduction and independently affects oil body formation in Marchantia polymorpha.

In angiosperms, basic leucine-zipper (bZIP) TGACG-motif-binding (TGA) transcription factors (TFs) regulate developmental and stress-related processes, the latter often involving NON EXPRESSOR OF PATHOGENESIS-RELATED GENES (NPR) coregulator interactions. To gain insight into their functions in an early diverging land-plant lineage, the single MpTGA and sole MpNPR genes were investigated in the liverwort Marchantia polymorpha. We generated Marchantia MpTGA and MpNPR knockout and overexpression mutants and conducted morphological, transcriptomic and expression studies.

B-GATA factors are required to repress high-light stress responses in Marchantia polymorpha and Arabidopsis thaliana.

GATAs are evolutionarily conserved zinc-finger transcription factors from eukaryotes. In plants, GATAs can be subdivided into four classes, A-D, based on their DNA-binding domain, and into further subclasses based on additional protein motifs. B-GATAs with a so-called leucine-leucine-methionine (LLM)-domain can already be found in algae.

Conserved redox-dependent DNA binding of ROXY glutaredoxins with TGA transcription factors.

The CC-type glutaredoxin (GRX) ROXY1 and the bZIP TGA transcription factor (TF) PERIANTHIA (PAN) interact in the nucleus and together regulate petal development. The CC-type GRXs exist exclusively in land plants, and in contrast to the ubiquitously occurring CPYC and CGFS GRX classes, only the CC-type GRXs expanded strongly during land plant evolution. Phylogenetic analyses show that TGA TFs evolved before the CC-type GRXs in charophycean algae.

The N-Terminus of the Floral Arabidopsis TGA Transcription Factor PERIANTHIA Mediates Redox-Sensitive DNA-Binding.

The Arabidopsis TGA transcription factor (TF) PERIANTHIA (PAN) regulates the formation of the floral organ primordia as revealed by the pan mutant forming an abnormal pentamerous arrangement of the outer three floral whorls. The Arabidopsis TGA bZIP TF family comprises 10 members, of which PAN and TGA9/10 control flower developmental processes and TGA1/2/5/6 participate in stress-responses. For the TGA1 protein it was shown that several cysteines can be redox-dependently modified.

Plant-specific CC-type glutaredoxins: functions in developmental processes and stress responses.

Glutaredoxins (GRXs) are small oxidoreductases of the thioredoxin family proteins that can either regulate the thiol redox state of proteins or are linked to iron metabolism because of their ability to incorporate iron-sulfur [2Fe-2S] clusters. Here we review recent research on a land plant-specific class of GRX-like proteins, which are characterized by the conserved CC motif in the active centre. Loss-of-function mutants of CC-type GRXs in Arabidopsis (also named ROXYs), maize, and rice have unraveled a role in floral development, including regulation of organ primordia initiation, control of organ identity gene expression, and progression into meiosis in the male germ line.

Regulation of plant cytosolic aldolase functions by redox-modifications.

From the five genes which code for cytosolic fructose 1,6-bisphosphate aldolases in Arabidopsis thaliana L., the cDNA clone of cAld2 (At2g36460), was heterologously expressed in E. coli and incubated under various oxidizing and reducing conditions.