New Study Uncovers Evolutionary Link in B6 Metabolism

An investigation conducted by a group of scientists at the University of Kentucky’s Martin-Gatton College of Agriculture, Food and Environment has uncovered an unexpected biochemical link between the immune responses of plants and the neurological health of humans.

The researchers identified that the metabolic pathways responsible for maintaining vitamin B6 levels vital for certain types of epilepsy and immune function are common to both plants and humans.

This research was published in the journal Nature Plants and received funding from the US National Science Foundation and the National Institute of Food and Agriculture, which is part of the US Department of Agriculture.

The findings underscore the significance of plant-based diets as a source of vital vitamins and amino acids, highlighting the profound biochemical relationships between plant resilience and human health.

Gaining insight into these shared metabolic pathways paves the way for advancements in both crop resilience and human nutrition.

The focus of the study is on lysine catabolism. Catabolism refers to the breakdown of nutrients, which is a component of metabolism the intricate series of chemical reactions that sustain life. Lysine is a crucial amino acid necessary for protein synthesis, collagen production, calcium absorption, and the creation of enzymes, hormones, and antibodies.

The researchers discovered that plants generate Δ1-piperideine-6-carboxylic acid (P6C) during the breakdown of lysine, paralleling a process in humans where elevated levels of P6C are associated with pyridoxine-dependent epilepsy. In plants, heightened P6C levels disrupt the balance of vitamin B6, leading to a depletion of essential B6 forms and weakening systemic immunity.

Our findings highlight the deep evolutionary processes that shape biochemical signaling across life forms. The same molecular pathways that regulate plant immunity are also involved in human neurological health, emphasizing how fundamental metabolites like vitamins and amino acids have been conserved throughout evolution.”

Huazhen Liu, Study Principal Investigator, University of Kentucky

Huazhen Liu is also a Postdoctoral Scholar at the Department of Plant Pathology, Martin-Gatton CAFE.

The research also provides insights into the evolutionary roots of these metabolic pathways. The scientists found that specific enzymes involved in lysine and proline metabolism in plants were likely obtained from bacterial sources via horizontal gene transfer.

Over time, these enzymes were adapted to help maintain vitamin B6 levels and detoxify transient, high-energy molecules known as reactive metabolic intermediates.

In addition to its implications for plant immunity, this finding highlights the broader influence of diet on human health. Vitamin B6, present in numerous plant-based foods, is crucial for neurotransmitter function, immune responses, and metabolism.

The study indicates that disturbances in amino acid metabolism could have extensive repercussions across biological systems, linking plant and human health in unforeseen ways.

It is important that we approach vitamin supplementation cautiously and rely primarily on plant-based diets to meet our daily nutritional needs.”

Pradeep Kachroo, Professor, University of Kentucky

Pradeep Kachroo is an American Association for the Advancement of Science Fellow and a prominent authority on plant systemic immunity.