In mid-September, the US Department of Agriculture (USDA) announced the preliminary release of the sequenced genome of the cacao tree. The effort is the result of a partnership between USDA's Agricultural Research Service (ARS); Mars, Inc. (McLean, Virginia, USA), one of the world's largest manufacturers of chocolaterelated products; scientists at IBM's Thomas J. Watson Research Center Yorktown, New York, USA); and researchers from the Clemson University Genomics Institute, the HudsonAlpha Institute for Biotechnology, Washington State University, Indiana University, the National Center for Genome Resources, and PIPRA (Public Intellectual Property Resource for Agriculture) at the University of California-Davis.
Cocoa comes from the cacao tree, Theobroma cacao. The seeds are processed into cocoa beans that are the source of cocoa, cocoa butter, and chocolate. Fungal diseases can destroy seed-bearing pods and wipe out up to 80% of the crop. Additionally, worldwide demand for cacao now exceeds production, and hundreds of thousands of small farmers and landholders throughout the tropics depend on cacao for their livelihoods. An estimated 70% of the world's cocoa is produced in West Africa. Scientists worldwide have been searching for years for ways to produce cacao trees that can resist evolving pests and diseases, tolerate droughts, and produce higher yields. ARS researchers have been testing new cacao tree varieties developed with genetic markers. But having the genome sequenced is expected to speed up the process of identifying genetic markers for specific genes that confer beneficial traits, enabling breeders to produce superior new lines through traditional breeding techniques.
Sequencing cacao's genome also will help researchers develop an overall picture of the plant's genetic makeup, uncover the relationships between genes and traits, and broaden scientific understanding of how the interplay of genetics and the environment determines a plant's health and viability.
Currently, 92% of the genome sequence has been released into the public domain, with access to these data online via the Cacao Genome Database (www.cacaogenomedb.org) prior to formal peer-reviewed publication. This release will enable the sequence data to be applied immediately to cacao genetic improvement.
Team leaders from the USDA included molecular biologist David Kuhn and geneticist Raymond Schnell, both at the ARS Subtropical Horticulture Research Station (Miami, Florida), as well as ARS computational biologist Brian Scheffler at the Jamie Whitten Delta States Research Center (Stoneville, Mississippi).
'Because of the talent and dedication brought together by this unique partnership, researchers and plant breeders will be able to accelerate the genetic improvement of the cacao crop now cultivated in tropical regions around the world,' said Edward B. Knipling, ARS administrator. 'This will benefit not only the chocolate industry, but also millions of small farmers who will be able to continue to make their living from cacao.'
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Cocoa beans in a cacao pod.
