The team’s new study, published in Nature Plants, identifies a class of previously unknown transport proteins called RETICULATA1 (RE1), which enable the exchange of key amino acids within plant cells.

Unlike humans, plants have the ability to synthesize all 20 proteinogenic amino acids, which is why plant-based foods are an essential part of a nutritious diet. Nine of these, including key building blocks like lysine and arginine, are produced only in plastids, such as chloroplasts.

Until now, it was unknown how these amino acids could pass through the chloroplast membrane.

“The molecular function of RE1 has been a mystery for decades, even though mutations in this gene cause conspicuous leaf shapes in the model plant Arabidopsis thaliana,” explained Andreas P.M. Weber, Heinrich Heine University Düsseldorf professor and corresponding author on the study. “Our research shows that RE1 is a specialized transporter for basic amino acids.”