Geneticists Fight Fungi on Cacao Plants

Author:  Jacob Weatherly
Institution:  Harvard College
Date:  November 2010

Chocolate is one of the top ten agricultural commodities in the world and provides income for 6.5 million farmers in Africa, South America, and Asia. However, pests and fungi have plagued chocolate production in the past, but scientists are beginning to get the upper hand. In September, researchers released a preliminary sequence of the cacao genome in hopes of developing disease-resistant strains.

Historically, fungi have been known to collapse an entire country's chocolate industry. Brazil, for example, used to be the second largest producer of cacao at 400,000 tons per year until a fungus infected almost all of the country's crops in the 1990s. Today, over 70% of the world's cacao are grown in Africa. There is still concern that reliance on beans from one region would spell disaster for the chocolate industry if a fungus infection occurs.

Fungal infection is of such great concern that the cacao industry has spent $700 million a year for the past 15 years combating these microscopic organisms. In light of this expense, Mars Inc.® (the maker of M&Ms and Snickers) saw fit to invest $10 million in The Genomics, Genetics and Breeding Resource for Cacao Improvement project. This program is a collaboration among Mars Inc., the US Department of Agriculture, IBM, the National Center for Genome Resources (NCGR), Clemson University, HudsonAlpha Institute for Biotechnology, Indiana University, and Washington State University.

The group has released a preliminary sequence of the cacao genome at Mars Inc. sees the Cacao Genome Database as a long-term investment. As Mars Inc.'s global staff officer of plant science and research, Howard-Yana Shapiro, explained, "Although it may not benefit the bottom line in the short term, in the long run, it will ensure mutually beneficial results for the company, cocoa farmers, and tree crop production in key regions of the world."

The researchers expect the genome to lead to the development of disease-resistant strains. Toward this end, the strain that the collaborators chose to sequence is Matina 1-6, which is commonly found in cacao-producing countries.

The current release of the genome is preliminary, so the researchers will be updating the sequence in the coming weeks. Then, they will turn their attention to mapping the genetic variability of cacao. The Computational Genomics Group at IBM's Computational Biology Center will accomplish this by identifying single nucleotide polymorphisms (SNPs), mutations in which a single nucleotide differs from the consensus sequence.

According to a statement on their website, Mars Inc. and its collaborators hope that the genome will "advance the science of cocoa for the benefit of everyone along the supply chain, starting with farmers first."


1. Boyle, Rebecca. "In Sweet Breakthrough, Scientists Led By Makers of M&Ms Sequence the Chocolate Genome." Popular Science 15 Sept 2010 .

2. The Cacao Genome Database,

3. Becker, Hank. "Fighting a Fungal Siege on Cacao Farms." United States Department of Agriculture Agricultural Research Service 22 March 2007. 15 Sept 2010 .

Author: Jacob Weatherly

Reviewed by: Mai Truong and Yangguang Ou

Published by: Maria Huang