For the first time, the genomes of the domesticated tomato and its wild ancestor, Solanum pimpinellifolium, have been sequenced by the Tomato Genome Consortium, an international collaboration of over 300 scientists from 13 countries.
The sequences, reported in this week’s issue of the journal Nature, provide the most detailed look yet at the tomato genome, revealing the order, orientation, types and relative positions of its 35,000 genes.
Tomato is a member of the Solanaceae or nightshade family, and the new sequences are expected to provide reference points helpful for identifying important genes in tomato’s Solanaceae relatives. The group includes potato, pepper, eggplant and petunia and is the world’s most important vegetable plant family in terms of both economic value and production volume. Plant members serve as sources of food, spices and medicines.
This breakthrough is expected to lower costs and speed up efforts to improve the worldwide tomato production, making it better equipped to combat the pests, pathogens, droughts and diseases that now plague growers. The new results will help researchers uncover the relationships between tomato genes and traits and broaden their understanding of how genetics and environmental factors interact to determine a field crop’s health and viability.
The sequences also offer insight into how the tomato has diversified and adapted to new environments. They show that the tomato genome expanded abruptly about 60 million years ago, at a time close to one of the large mass extinctions. Subsequently, most of this genetic redundancy was lost. Some of the genes generated during that event survive till today and control some of the most appealing traits of tomato.
“The tomato is the model system for studying fruit development,” said Bruce Roe, George L. Cross Research Professor Emeritus in the University of Oklahoma’s College of Arts and Sciences, one of the US scientists participating in the Consortium.
“The significance of obtaining the highly accurate genome structure of the tomato is that it has helped us gain a greater understanding of the genes controlling fruit characteristics and processes, such as those involved in fruit color, flavor and texture.”
Previous efforts have led to the sequencing of a number of other crop plants, including rice, corn, sorghum, poplar, potato, soybean, grape and Arabidopsis thaliana, a plant widely studied as a model organism.
Bibliographic information: Sato S. et al. 2012. The tomato genome sequence provides insights into fleshy fruit evolution. Nature 485, 635–641. doi:10.1038/nature11119