Degradation of BOR1 transporter in response to high B supply. The images show fluorescence derived from BOR1-GFP in root tips. BOR1-GFP was transferred from the plasma membrane to the vacuole for degradation.

Plants take up and translocate nutrients through transporters (Keyword 1). Boron (B) is essential for plant growth and survival due to its function in cross-liking pectin in the cell wall. Similar to most essential nutrients, excessive supply of B inhibits plant growth. Since both B deficiency and toxicity are agricultural problems worldwide, it is important to understand the mechanisms for plants to cope with changing B conditions.

Using Arabidopsis (Keyword 2) as a model plant, we revealed that BOR1, a key transporter for B translocation in plants, is a transporter-receptor—a so-called “transceptor”. Our results suggested that BOR1 directly senses the B concentration during the transport cycle and promotes its own degradation under high-B conditions. This is a simple and efficient mechanism for maintenance of nutrient acquisition at appropriate levels. This finding will lead to develop plants or methods for sustainable crop production with reduced fertilizer use.

Paper

Title

「Transport-coupled ubiquitination of the borate transporter BOR1 for its boron-dependent degradation」

• The Plant Cell Website

Authors

Akira Yoshinari (Osaka Prefecture University, Nagoya University), Takuya Hosokawa (Osaka Prefecture University), Marcel Pascal Beier (Osaka Prefecture University, The University of Tokyo), Keishi Oshima (Osaka Prefecture University), Yuka Ogino, Chiaki Hori, Taichi E. Takasuka (Hokkaido University), Yoichiro Fukao (Ritsumeikan University), Toru Fujiwara (The University of Tokyo) , Junpei Takano (Osaka Prefecture University)

Keywords

Keyword 1: Transporter

A type of membrane protein which transport substances such as nutrients across the biological membranes. A transporter binds to a substrate from one side of the membrane and changes its conformation to transport the substrate to the other side.

Keyword 2: Arabidopsis（Arabidopsis thaliana）

A small flowering plant in the family Brassicaceae. Arabidopsis possesses relatively small genome and properties useful for molecular biology. This was the first plant whose genome was sequenced.

Contribution to the SDGs

2: Zero hunger
15: Life on land