Scientists Sequence Tomato Genome
May 30, 2012

Scientists Sequence Tomato Genome

Lee Rannals for

If you ever wondered what makes the sauce on a pizza taste so good, wonder no more because scientists have unraveled the genetic make-up of a tomato.

Scientists report in the journal Nature that they have performed a full genome sequence from the "Heinz 1706" tomato.

The researchers say that tomatoes possess about 35,0000 genes arranged on 12 chromosomes.

"For any characteristic of the tomato, whether it's taste, natural pest resistance or nutritional content, we've captured virtually all those genes," James Giovannoni, a scientist at the Boyce Thompson Institute for Plant Research, said.

The genome sequence of the genes and their arrangement helps provide insight into the evolution of the fruit, the researchers wrote in the journal.

"Tomato genetics underlies the potential for improved taste every home gardener knows and every supermarket shopper desires and the genome sequence will help solve this and many other issues in tomato production and quality," Giovannoni said.

Identifying signals that may suggest key episodes of evolution of a species is done by extensively comparing genomes.  During the study, the tomato genome was compared with several closely related species, including potatoes and grapes.

These comparisons show that the tomato genome has undergone complete duplications during its evolution.

The researchers found that there is empirical proof that the tomato's genome has experienced two rounds of triplications over the past 120 million years of its evolution. One of them probably took place before grapes and tomatoes evolved along different paths, according to the findings.

The study also revealed that these triplications had a particular impact on the genes that control features like texture, color and maturation.

The research paves the way for future tomatoes to be sequenced. Now that they have completed a full genome sequence on one variety of tomato, it makes it easier and less expensive for seed companies and plant breeders to sequence other varieties for research and development.

The first tomato genome sequence cost millions of dollars, but sequencing other varieties of tomatoes may now only run about $10,000, because the groundwork is mostly completed.

The sequencing of the tomato genome has implications for other plant species, such as strawberries, apples, melons, bananas and other fleshy fruits. These types of fruits share characteristics with tomatoes, so information about the genes and pathways involved in fruit ripening can potentially be applied to them.

"Now we can start asking a lot more interesting questions about fruit biology, disease resistance, root development and nutritional qualities," said Giovannoni.

Tomatoes are a $2 billion industry in the U.S., and the UDSA estimates that Americans consume over 72 pounds of tomato products annually.