Hidden role of plant waxes in environmental communication

Researchers from the University of Toronto Scarborough have revealed that the protective waxy barrier surrounding plants may be crucial in sending chemical signals to other plants and insects

This research, published in the Proceedings of the National Academy of Science, opens up possibilities for engineering stronger, more resilient plants capable of thriving in challenging environmental conditions.

Waxy barriers as chemical messengers

Cuticular waxes, a thin layer plants deposit on their surfaces to prevent water loss, were traditionally believed to act solely as physical defences. According to Assistant Professor Eliana Gonzales-Vigil, the study’s leader, these waxes shield plants from ultraviolet radiation, fungi, bacteria, and temperature extremes while also fending off insects.

Contrary to the previous assumption that these waxes remain stable and unreactive, the research found that certain waxes break down upon exposure to air and light, releasing compounds that play a pivotal role in plant communication.

Cuticular waxes

The study focused on analysing waxes in poplar trees, specifically cottonwood. Researchers discovered that unsaturated waxes, referred to as alkenes, degrade to produce a well-known aldehyde signalling compound and insect pheromone called nonanal. Gonzales-Vigil emphasises that this unexpected breakdown of waxes could be down to engineering desirable traits in plants, enhancing their resilience to drought or insect infestations.

Aldehydes, recognised as signalling molecules in plants and animals, influence growth, development, and reproduction. In plants, they are present in pheromones that attract insects and facilitate plant-to-plant communication. For instance, when a plant experiences stress due to drought, it releases compounds to signal neighbouring plants to prepare for similar conditions.

Jeff Chen, a recent master’s graduate in cell and systems biology at University of Toronto Scarborough discovered this accidental breakdown of waxes while tracking the ageing process of poplar leaves. The unexpected decrease in wax abundance and simultaneous increase in volatile compounds, such as aldehydes, intrigued the researchers.

Crop resilience

This discovery’s potential applications hope to improve crop resilience, as alkenes, the precursors to aldehydes, are found in specialised waxes in some plants. The research team found that corn silk and wheat also exhibited similar wax breakdown patterns, suggesting broader applications for enhancing agricultural practices.

The research opens opportunities for advancing plant science and agricultural practices, paving the way for a greener and more sustainable future.