Boron in plants and animals: Is there a role beyond cell-wall structure?

The role of boron (B) as a structural element of plant cell walls and its implications for plant growth have been well established. However, increasing evidence suggests one or more functions of boron beyond cell-wall structure. This evidence arises from studies conducted with a large variety of organisms, such as plants, animals, and bacteria. In animals, embryogenic development seems to depend on adequate boron supply, and cell lines with a knockout of the Na+-coupled boron transporter NaBC1, the mammalian homolog of Arabidopsis thaliana boron transporter AtBor1, stop to develop and proliferate. In bacteria, boron is an essential part of a signal molecule required for quorum sensing. This review aims to summarize some recent advances from plant, animal, and microbiological research related to the functions of boron and to highlight open questions for further research.