Ethylene Biosynthesis and Regulation in Plant Systems

Ethylene is a gaseous phytohormone that orchestrates a wide array of developmental processes and stress responses in plants, including seed germination, fruit ripening, leaf abscission and adaptation to environmental challenges. Its biosynthesis follows a conserved two-step pathway: S-adenosyl-L-methionine (SAM) is first converted to 1-aminocyclopropane-1-carboxylic acid (ACC) by ACC synthases (ACSs), and ACC is subsequently oxidised to ethylene by ACC oxidases (ACOs). Regulation of this pathway is highly complex, occurring at transcriptional, post-transcriptional and post-translational levels. Transcription factors modulate ACS and ACO gene expression in response to developmental cues and external stimuli, while protein stability and activity are adjusted through phosphorylation, ubiquitination and hormonal crosstalk. Moreover, ACC itself can be conjugated, transported over long distances and even act as an ethylene-independent signal. Interactions with other hormones, such as cytokinins, auxins and abscisic acid, fine-tune ethylene production both spatially and temporally. Understanding these regulatory networks has significant implications for agriculture, offering routes to enhance crop yield, stress resistance and post-harvest quality through targeted manipulation of ethylene biosynthesis and signalling.

Research from Nature Portfolio

Recent studies have revealed that ACC functions beyond its role as a mere precursor to ethylene. Investigations in Arabidopsis ovules demonstrated that ACC triggers transient calcium influxes via glutamate receptor-like channels, promoting secretion of a pollen-tube attractant independently of ethylene production or canonical signalling. This finding uncovers a novel signalling role for ACC in reproductive development. The work highlights how precursor molecules in hormone pathways can possess autonomous bioactivity and reshapes our understanding of ethylene-related regulatory circuits.

Ethylene Biosynthesis and Regulation in Plant Systems publication trend

The graph below shows the total number of articles in ethylene biosynthesis and regulation in plant systems across all publications each year (not limited to Nature Index journals).

Technical terms

Ethylene: A simple gaseous hormone (C₂H₄) that regulates plant growth, development and stress responses.

S-adenosyl-L-methionine (SAM): A universal methyl donor that serves as the substrate for ACC synthase in ethylene biosynthesis.

1-Aminocyclopropane-1-carboxylic acid (ACC): The immediate precursor of ethylene, produced by ACS enzymes and oxidised by ACO enzymes; also functions as an independent signalling molecule.

ACC synthase (ACS): A family of enzymes catalysing the conversion of SAM to ACC; often rate-limiting and subject to multilayered regulation.

ACC oxidase (ACO): The enzyme responsible for the oxidation of ACC to ethylene; its activity and expression are modulated by developmental and environmental cues.

Cytokinin: A class of phytohormones that interact with ethylene biosynthesis pathways to regulate cell division, differentiation and organ growth.

References

1. Cytokinins regulate spatially specific ethylene production to control root growth in Arabidopsis. Plant Communications (2024).
2. Genome-Wide Analysis and Identification of 1-Aminocyclopropane-1-Carboxylate Synthase (ACS) Gene Family in Wheat (Triticum aestivum L.). International Journal of Molecular Sciences (2023).
3. The regulation of ethylene biosynthesis: a complex multilevel control circuitry. New Phytologist (2020).
4. Accumulation and Transport of 1-Aminocyclopropane-1-Carboxylic Acid (ACC) in Plants: Current Status, Considerations for Future Research and Agronomic Applications. Frontiers in Plant Science (2017).
5. Ethylene-independent signaling by the ethylene precursor ACC in Arabidopsis ovular pollen tube attraction. Nature Communications (2020).