Arabidopsis plants use a gatekeeper protein to shuffle Vitamin B2 into their reproductive organs.

Vitamin B2 is essential for all life, yet the mechanism for how plants move it across their cell membranes remained a total mystery until now. The AtPUP5 protein is the first genetically defined transporter found to handle the distribution of this vital nutrient. Without this transporter, the plant cannot properly feed its developing seeds or manage its internal energy cycles. This discovery fills a massive gap in the basic blueprint of plant physiology and nutrient transport. Plant breeders can now look for similar transporters in food crops to potentially increase their vitamin content.