The genomes of charophyte green algae, close relatives of land plants, typically do not show signs of developmental regulation by phytohormones. However, scattered reports of endogenous phytohormone production in these organisms exist. We performed a comprehensive analysis of multiple phytohormones in Viridiplantae, focusing mainly on charophytes. We show that auxin, salicylic acid, ethylene and tRNA-derived cytokinins including cis-zeatin are found ubiquitously in Viridiplantae. By contrast, land plants but not green algae contain the trans-zeatin type cytokinins as well as auxin and cytokinin conjugates. Charophytes occasionally produce jasmonates and abscisic acid, whereas the latter is detected consistently in land plants. Several phytohormones are excreted into the culture medium, including auxin by charophytes and cytokinins and salicylic acid by Viridiplantae in general. We note that the conservation of phytohormone biosynthesis and signaling pathways known from angiosperms does not match the capacity for phytohormone biosynthesis in Viridiplantae. Our phylogenetically guided analysis of established algal cultures provides an important insight into phytohormone biosynthesis and metabolism across Streptophyta.

• MeSH
• Biological Evolution MeSH
• Chlorophyta metabolism   genetics   MeSH
• Cyclopentanes metabolism   MeSH
• Cytokinins * metabolism   MeSH
• Ethylenes metabolism   MeSH
• Phylogeny * MeSH
• Abscisic Acid metabolism   MeSH
• Salicylic Acid metabolism   MeSH
• Indoleacetic Acids * metabolism   MeSH
• Oxylipins metabolism   MeSH
• Gene Expression Regulation, Plant MeSH
• Plant Growth Regulators * metabolism   MeSH
• Signal Transduction MeSH
• Viridiplantae metabolism   genetics   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Cyclopentanes MeSH
• Cytokinins * MeSH
• ethylene MeSH Browser
• Ethylenes MeSH
• jasmonic acid MeSH Browser
• Abscisic Acid MeSH
• Salicylic Acid MeSH
• Indoleacetic Acids * MeSH
• Oxylipins MeSH
• Plant Growth Regulators * MeSH