Auxin, indole-3-acetic acid (IAA), is a key phytohormone with diverse morphogenic roles in land plants, but its function and transport mechanisms in algae remain poorly understood. We therefore aimed to explore the role of IAA in a complex, streptophyte algae Chara braunii. Here, we described novel responses of C. braunii to IAA and characterized two homologs of PIN auxin efflux carriers: CbPINa and CbPINc. We determined their localization in C. braunii using epitope-specific antibodies and tested their function in heterologous land plant models. Further, using phosphoproteomic analysis, we identified IAA-induced phosphorylation events. The thallus regeneration assay showed that IAA promotes thallus elongation and side branch development. Immunolocalization of CbPINa and CbPINc confirmed their presence on the plasma membrane of vegetative and generative cells of C. braunii. However, functional assays in tobacco BY-2 cells demonstrated that CbPINa affects auxin transport, whereas CbPINc does not. The IAA is effective in the acceleration of cytoplasmic streaming and the phosphorylation of evolutionary conserved targets such as homolog of RAF-like kinase. These findings suggest that, although canonical PIN-mediated auxin transport mechanisms might not be fully conserved in Chara, IAA is involved in morphogenesis and fast signaling processes.

• Keywords
• Chara, auxin transport, indole‐3‐acetic acid, plant evolution, streptophytes,
• MeSH
• Biological Transport drug effects   MeSH
• Cell Membrane metabolism   drug effects   MeSH
• Chara * metabolism   drug effects   MeSH
• Phosphorylation drug effects   MeSH
• Indoleacetic Acids * metabolism   pharmacology   MeSH
• Membrane Transport Proteins * metabolism   MeSH
• Plant Proteins * metabolism   MeSH
• Nicotiana metabolism   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• indoleacetic acid MeSH Browser
• Indoleacetic Acids * MeSH
• Membrane Transport Proteins * MeSH
• Plant Proteins * MeSH

Gene expression regulation during tissue development is extremely complex. A key mechanism of gene regulation is the recognition of regulatory motifs, also known as cis-regulatory elements (CREs), by various proteins in gene promoter regions. Localization of these motifs near the transcription start site (TSS) or translation start site (ATG) is crucial for transcription initiation and rate. Transcription levels of individual genes, regulated by these motifs, can vary significantly across tissues and developmental stages, especially in processes like sexual reproduction. However, the precise localization and visualization of these motifs in relation to gene expression in specific tissues can be challenging. Here, we introduce a freely available tool called GOLEM (Gene regulatOry eLEMents; https://golem.ncbr.muni.cz), which enables users to precisely locate any motif of interest with respect to TSS or ATG within the relevant plant genomes across the plant Tree of Life (Chara, Marchantia, Physcomitrium, Azolla, Ceratopteris, Amborella, Oryza, Zea, Solanum and Arabidopsis). The visualization of the motifs is performed with respect to the transcript levels of particular genes in leaves and male reproductive tissues and can be compared with genome-wide distribution regardless of the transcription level. Additionally, genes with specific CREs at defined positions and high expression in selected tissues can be exported for further analysis. GOLEM's functionality is illustrated by its application to conserved motifs (e.g. TATA-box, ABRE, I-box, and TC-element), hormone-responsive elements (GCC-box, ARR10_binding motif), as well as to male gametophyte-related motifs (e.g., LAT52, MEF2, and DOF_core).

• Keywords
• GOLEM, Gene regulatOry eLEMents, TSS, gametophyte, motif localization, plant genes, promoter elements, technical advance,
• MeSH
• Arabidopsis genetics   MeSH
• Genome, Plant genetics   MeSH
• Transcription Initiation Site MeSH
• Promoter Regions, Genetic * genetics   MeSH
• Pollen * genetics   MeSH
• Gene Expression Regulation, Plant genetics   MeSH
• Software * MeSH
• Publication type
• Journal Article MeSH

Chara has been used as a model for decades in the field of plant physiology, enabling the investigation of fundamental physiological processes. In electrophysiological studies, Chara has been utilized thanks to its large internodal cells that can be easily manipulated. Additionally, Chara played a pioneering role in elucidating the presence and function of the cytoskeleton in cytoplasmic streaming, predating similar findings in terrestrial plants. Its representation considerably declined following the establishment and routine application of genetic transformation techniques in Arabidopsis. Nevertheless, the recent surge in evo-devo studies can be attributed to the whole genome sequencing of the Chara braunii, which has shed light on ancestral traits prevalent in land plants. Surprisingly, the Chara braunii genome encompasses numerous genes that were previously regarded as exclusive to land plants, suggesting their acquisition prior to the colonization of terrestrial habitats. This review summarizes the established methods used to study Chara, while incorporating recent molecular data, to showcase its renewed importance as a model organism in advancing plant evolutionary developmental biology.

• Keywords
• Chara, Charophytes, Model plants, Plant evolution,
• MeSH
• Biological Evolution MeSH
• Chara * MeSH
• Cytoplasmic Streaming MeSH
• Plants genetics   MeSH
• Embryophyta * MeSH
• Publication type
• Journal Article MeSH
• Review MeSH

Cytokinins (CKs) and ethylene (ET) are among the most ancient organic chemicals on Earth. A wide range of organisms including plants, algae, fungi, amoebae, and bacteria use these substances as signaling molecules to regulate cellular processes. Because of their ancestral origin and ubiquitous occurrence, CKs and ET are also considered to be ideal molecules for inter-kingdom communication. Their signal transduction pathways were first historically deciphered in plants and are related to the two-component systems, using histidine kinases as primary sensors. Paradoxically, although CKs and ET serve as signaling molecules in different kingdoms, it has been supposed for a long time that the canonical CK and ET signaling pathways are restricted to terrestrial plants. These considerations have now been called into question following the identification over recent years of genes encoding CK and ET receptor homologs in many other lineages within the tree of life. These advances shed new light on the dissemination and evolution of these hormones as both intra- and inter-specific communication molecules in prokaryotic and eukaryotic organisms.

• Keywords
• cell signaling, cytokinins, ethylene, histidine kinases, receptors,
• MeSH
• Cytokinins metabolism   MeSH
• Ethylenes metabolism   MeSH
• Eukaryota metabolism   MeSH
• Humans MeSH
• Prokaryotic Cells metabolism   MeSH
• Signal Transduction physiology   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Review MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH
• Names of Substances
• Cytokinins MeSH
• ethylene MeSH Browser
• Ethylenes MeSH

Within streptophyte green algae Zygnematophyceae are the sister group to the land plants that inherited several traits conferring stress protection. Zygnema sp., a mat-forming alga thriving in extreme habitats, was collected from a field site in Svalbard, where the bottom layers are protected by the top layers. The two layers were investigated by a metatranscriptomic approach and GC-MS-based metabolite profiling. In the top layer, 6569 genes were significantly upregulated and 149 were downregulated. Upregulated genes coded for components of the photosynthetic apparatus, chlorophyll synthesis, early light-inducible proteins, cell wall and carbohydrate metabolism, including starch-degrading enzymes. An increase in maltose in the top layer and degraded starch grains at the ultrastructural levels corroborated these findings. Genes involved in amino acid, redox metabolism and DNA repair were upregulated. A total of 29 differentially accumulated metabolites (out of 173 identified ones) confirmed higher metabolic turnover in the top layer. For several of these metabolites, differential accumulation matched the transcriptional changes of enzymes involved in associated pathways. In summary, the findings support the hypothesis that in a Zygnema mat the top layer shields the bottom layers from abiotic stress factors such as excessive irradiation.

• MeSH
• Chlorophyta genetics   metabolism   MeSH
• Ecosystem MeSH
• Photosynthesis genetics   MeSH
• Stress, Physiological MeSH
• Metabolome MeSH
• Streptophyta genetics   metabolism   MeSH
• Transcriptome MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Geographicals
• Arctic Regions MeSH
• Svalbard MeSH

: Jasmonic acid (JA) and its related derivatives are ubiquitously occurring compounds of land plants acting in numerous stress responses and development. Recent studies on evolution of JA and other oxylipins indicated conserved biosynthesis. JA formation is initiated by oxygenation of α-linolenic acid (α-LeA, 18:3) or 16:3 fatty acid of chloroplast membranes leading to 12-oxo-phytodienoic acid (OPDA) as intermediate compound, but in Marchantiapolymorpha and Physcomitrellapatens, OPDA and some of its derivatives are final products active in a conserved signaling pathway. JA formation and its metabolic conversion take place in chloroplasts, peroxisomes and cytosol, respectively. Metabolites of JA are formed in 12 different pathways leading to active, inactive and partially active compounds. The isoleucine conjugate of JA (JA-Ile) is the ligand of the receptor component COI1 in vascular plants, whereas in the bryophyte M. polymorpha COI1 perceives an OPDA derivative indicating its functionally conserved activity. JA-induced gene expressions in the numerous biotic and abiotic stress responses and development are initiated in a well-studied complex regulation by homeostasis of transcription factors functioning as repressors and activators.

• Keywords
• JA biosynthetic enzymes, JA bypass, JA signaling, Jasmonic acid (JA) metabolites, active JA compounds, occurrence, transcription factors,
• MeSH
• Chloroplasts metabolism   MeSH
• Cyclopentanes metabolism   MeSH
• Species Specificity MeSH
• alpha-Linolenic Acid metabolism   MeSH
• Marchantia metabolism   MeSH
• Fatty Acids metabolism   MeSH
• Bryopsida metabolism   MeSH
• Metabolic Networks and Pathways MeSH
• Fatty Acids, Unsaturated metabolism   MeSH
• Oxylipins metabolism   MeSH
• Peroxisomes metabolism   MeSH
• Publication type
• Journal Article MeSH
• Review MeSH
• Names of Substances
• 12-oxophytodienoic acid MeSH Browser
• Cyclopentanes MeSH
• jasmonic acid MeSH Browser
• alpha-Linolenic Acid MeSH
• Fatty Acids MeSH
• Fatty Acids, Unsaturated MeSH
• Oxylipins MeSH