Saving America’s Chestnut Trees with Wheat and Chromatography

Many people first encounter chromatography in school when they separate ink spots into their component colours — they then see a scene in CSI where a crime is solved using GC-MS. But chromatography offers much more… A team from the Oak Ridge National Laboratory (ORNL) in Tennessee and the State University of New York has recently used chromatography to help reintroduce a tree into the forests of the USA — the American chestnut. Let’s see how chromatography offers much more than separating ink spots.

Blight and Trees

A blight is a plant disease, typically caused by a fungal or bacterial infection. It often attacks the young shoots or growing tissues of a plant and can lead to the death of the plant. With severe infestations, all of plants in a certain species can be affected leading to a species failing in a growing season — or in the case of trees, whole populations of a species can be wiped out. One of the main concerns about tree blights is the risk of infection from overseas. Native trees are likely to have some resistance to native infections — as they probably evolved together. The problem comes when the infection is imported. Then it can be deadly.

Death of the American Chestnut

It is thought that the chestnut blight Cryphonectria parasitica — an Asian fungus — was accidently imported into the USA at the end of the nineteenth century. It was first identified in chestnut trees in New York’s Bronx Zoo in 1904, and quickly spread throughout chestnut trees. The native trees had little resistance to the imported blight. By the 1950s the majority of American chestnut trees along the Eastern seaboard had been affected — and a tree that had one time made up a quarter of forests had dwindled to a handful of large trees and a few saplings. In 1983 — with the formation of The American Chestnut Foundation (TACF) — the fight back started.

Wheat Genes and Oxalate

The chestnut blight fungus is so virulent because it produces a chemical compound called oxalate — (C₂O₄)^2- — which causes the tissues in the chestnut tree to rot. The researchers have found that the addition of a gene from wheat, oxalate oxidase, breaks down the oxalate formed by the fungus helping to preserve the trees.

Because the transgenic trees have been altered the team had to check that they were safe to re-introduce to the wild. By analysing the chestnuts from the trees using gas chromatography-mass spectrometry they found that the chestnuts from the transgenic trees had a similar metabolic composition to non-transgenic chestnuts, suggesting that the chestnuts would be edible and so safe for animals to eat.

For further details about the power of chromatography to enhance ours lives take a look at this article on coffee or this one on tigers.

Image Source: Chestnut Tree