The research team led by Professor Sangho Lee in the department of biological sciences (first author Yeongmok Lee) has uncovered a crucial puzzle piece regarding how plants respond to environmental stress and survive through the collaboration with Korea Brain Research Institute, the Korea Basic Science Institute and the Rural Development Administration. They elucidated the structural basis for the activation mechanism of the SLAC1 anion channel, a master switch of plant stomatal regulation, using cryo-electron microscopy (cryo-EM).

Tiny pores called stomata exist on the surface of plant leaves, allowing the absorption of carbon dioxide for photosynthesis and the release of oxygen. However, stomata can cause significant water loss during the drought and serve as entry points for pathogens. To overcome the limitations, plants have evolved the SLAC1 anion channel, which regulate stomatal closure in response to drought, pathogens, carbon dioxide, ozone, and other environmental factors. However, reports indicate that the precise stomatal regulation is being disrupted due to rapid increases in temperature and carbon dioxide resulting from climate change.

Given the importance of stomatal regulation, extensive researches have been conducted over the past decade to understand how the SLAC1 responds to stress and becomes activated. However, activation mechanism of the SLAC1 remains elusive and two alternative hypotheses have been suggested from previous studies. The research team determined the SLAC1 structures in open and closed states using cryo-EM and proposed a novel activation mechanism that accommodates two hypotheses from previous studies. This study revealed a two-step activation process involving phosphorylation-induced inhibition release and subsequent binding activation.

Prof. Sangho Lee remarked, "Through this study, the mystery of how plants detect stress and regulate stomata has finally been unveiled. This knowledge opens up the possibility for various applied researches, such as climate change adaptation and stress resistance through stomatal regulation." He also said, “It shows a research case using cryo-EM, a state-of-the-art device recently introduced in our university, emphasizing its potential for producing outstanding research outcomes.”

The research was published online in Nature Communications (IF: 17.694) on November 14th.

※ Title: Cryo-EM structures of the plant anion channel SLAC1 from Arabidopsis thaliana suggest a combined activation model

※ DOI: https://doi.org/10.1038/s41467-023-43193-3

※ Author: Yeongmok Lee (first author), Seoyeon Jung, Chi Truc Han Le, Prof. Sangho Lee (corresponding author)

Figure 1. Open and closed structures of anion channel SLAC1

Figure 2. A combined activation mechanism of anion channel SLAC1