"The large amount of information generated by this project dramatically changes the status of this tropical plant and its potential interest for the scientific community," said Guiltinan, professor of plant molecular biology, Penn State.
The researchers not only sequenced the genome of this ancient plant, but assembled 76 percent of the genome linking 82 percent of those genes to the 10 cacao chromosomes. This analysis identified a variety of gene families that may have future impact on improving cacao trees and fruit either by enhancing their attributes or providing protection from fungal diseases and insects that effect cacao trees.
"Relics of the ancestral Criollo first cultivated by Olmec or Maya people can still be encountered in old Mesoamerican plantations or in forests where the Maya live," said Siela Maximova, associate professor of horticulture and a member of the research team. "Our genome sequence is derived form a Belizean Criollo plant collected in the Mayan mountains."
Cocoa production began in Mesoamerica 3,000 years ago, and the Criollo variety was the first domesticated. Because these trees self-pollinate, they are generally highly homozygous -- possessing two identical forms of each gene, making this particular variety a good choice for accurate genome assembly.
Although originally a new-world crop, cacao trees -- scientifically designated Theobroma cocao -- are now grown and cultivated in humid, tropical areas around the world. About 3.7 million tons of cocoa are produced annually worldwide and contribute greatly to the income of small farmers. Cacao trees, because they are grown in shade, are also ideal for environmental preservation because they contribute to diversity and land rehabilitation.
"We believe that Theobroma cacao is the first early domesticated tropical tree fruit crop to be sequenced," said Guiltinan. "Interestingly, only 20 percent of the genome was made up of transposable elements."
Transposable elements or transposons are one of the natural pathways through which genetic sequences changes. They do this by moving around the chromosomes, changing the order of the genetic material. Smaller amounts of transposons than average could lead to slower evolution of the chocolate plant.
Guiltinan and his colleagues are interested in specific gene families that could link to specific cocoa qualities or disease resistance. They hope that mapping these gene families will lead to a source of genes directly involved in variations in the plant that are useful for acceleration of plant breeding programs.
"We hope this achievement will encourage greater investment in research of Theobroma cacao, the 'food of the Gods' whose magic flavor has spread worldwide since the time of the Maya and Aztec civilizations, and whose continued study will benefit developing countries for which cocoa is of high economic importance," said Guiltinan.
A summary of the paper appears in Nature Precedings at http://precedings.nature.com/documents/4908/version/1
Penn State researchers involved in this study include Guiltinan and Maximova, department of horticulture; Yufan Zhang and Zi Shi, graduate students, plant biology; Stephen Schuster, department of biochemistry and molecular biology; John E. Carlson, School of Forest Resources and M.J. Axtell and Z. Ma, department of biology.
Other researchers involved were from CIRAD, Institut National de la Recherche Agronomique UMR, Universite d'Evry, INRA-CNRS LIPM Laboratoire des Interactions Plantes Micro-organismes, Universite de Perpignan, Unite de Biometrie et d'Intelligence Artificielle , Institut des Sciences du vegetal, Chocolaterie Valrhona, all in France.
Also included are researchers from the University of Arizona; Cold Spring Harbor Laboratory; Institute des Sciences du Vegetal, Ivory Coast; CEPLAC, Brazil and Centro Nacional de Biotecnologia Agricola, Instituto de Estudios Avanzados,Venezuela.
CIRAD, the Agropolis foundation, the Région Languedoc Roussillon, Agence Nationale de la Recherche (ANR), Valrhona, the Venezuelan Ministry of Science, Technology and Industry, Hershey Corp., the American Cocoa Research Institute Endowment and National Science Foundation supported this work.
A'ndrea Elyse Messer | EurekAlert!
Alkaline soil, sensible sensor
03.08.2017 | American Society of Agronomy
New 3-D model predicts best planting practices for farmers
26.06.2017 | Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
21.08.2017 | Medical Engineering
21.08.2017 | Materials Sciences
21.08.2017 | Life Sciences