Vitamin B6 Role in Plants Discovered

Researchers from the University of Geneva (UNIGE), Switzerland, have discovered an unexpected role for Vitamin B6 in relation to nitrogen metabolism. Vitamin B6, a micronutrient, exists in different natural forms called vitamers. The study indicates that one of the vitamers informs the plant of its content in ammonium, a basic nitrogen compound needed for the biosynthesis of various molecules essential for life, such as proteins.

Together with colleagues from Max Planck Institute of Molecular Plant Physiology and the University of Düsseldorf (Germany), the researchers examined a version of Arabidopsis, which is defective in PDX3 enzyme, and displayed strongly impaired growth and development. PDX3-defective plants cannot transform the vitamer PMP. The researchers found that the growth anomalies were completely abrogated when the plants were supplemented with ammonium. The high levels of PMP in the PDX3-defective plants interfere with the conversion of nitrate into ammonium, resulting in an ammonium deficiency that is responsible for the impaired growth and development. The researchers further examined the interactions between nitrogen and Vitamin B6 in natural wild-type plants and observed a considerable accumulation of the PMP vitamer in plants supplemented with ammonium.

While scientists knew that plants acquired nitrogen from nitrate or ammonium to meet their needs, they were uncertain of how the plant monitored the level or proportion of these compounds. They found the vitamer PMP as the unanticipated player in this process. The group is currently investigating whether PMP regulates nitrogen metabolism directly or indirectly, via the action of other compounds.

For more details, read the news article at the University of Geneva website.