Saturday July 22, 2017

Chocolate plants get fungus armour from their parents

Cacao pods containing cocoa beans hang from a tree on a farm in Tulua, Colombia.

Cacao pods containing cocoa beans hang from a tree on a farm in Tulua, Colombia. (REUTERS)

Listen 7:40

Chocolate makers have been facing a global shortage of cacao seeds — the main ingredient in chocolate — for several years. One major contributor to the shortage has been that cacao farms have been suffering from infections from harmful fungi and other pathogens.

A new study has now shown that the microbiome of the cacao plants can naturally protect them against these pathogens, and that they can pass on that protection to younger plants - if given the opportunity.

Natalie Christian is a PhD candidate at Indian University and the lead author of this study. She has been working at the Smithsonian Tropical Research Institute in Panama studying the growth of cacao plants.

The study compared the effects of these pathogens on plants that been grown with leaves of adult plants, to those that were grown in more sterile conditions. They found that the plants grown in contact with leaf litter were colonized by a "good" fungus which protected the young plants from being damaged by the harmful pathogens.

This process is analogous to the way humans and other animals get good microbes from their mothers when they are born.

This research could inform cacao growers, which are generally grown in farms where fallen leaves and dead plants are removed from the fields - possibly removing the source of the protective fungi.