February 26, 2013

Watermelon: Delicious or Disease-Resistant

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The sweet, succulent crunch of a juicy watermelon comes at a price – the familiar red watermelons are highly susceptible to diseases, thus causing millions of dollars of loss for farmers. Prof. Zhangjun Fei, plant genomics, has uncovered a solution to this problem.

Fei realized that wild watermelons, which have white flesh and bitter taste, were more resistant to diseases. After generating a comparison of watermelon DNA sequences, he and his team concluded that these disease-resistant genes were lost during domestication of watermelon.

“We found that during domestication, people only focus on developing sweet watermelons, but they ignore the disease-resistance aspect. And when we compared those genomes, we found a lot of pathogen-resistant genes in wild watermelons that were lost in the cultivated one. That’s unfortunate, so now we want to bring back the disease-resistance,” Fei said.

Fei worked with researchers from several countries such as China and France, to complete the project.

“[Collaborating] helped a lot. If it were only my group, we would not have been able to do the project because we don’t have certain expertise or facilities,” Fei said.

Fei’s research focuses on using computational tools and system biology to analyze large amounts of information. Such analysis helps the team understand how genes function in living cells, he said.

The technology generates large fragments of the genome and later connects them “like a puzzle” so  Fei and his team have the complete sequence of the watermelon plant.

To simplify the process of generating 20 different watermelon sequences, the team first created a “reference genome” from the one watermelon. The team used this reference as a template in order to find the other watermelon genes more efficiently, as all of the plants have similar genetic sequences, Fei said.

Fei and his team are currently working on the introduction of disease-resistant genes into cultivated plants. This is not a simple process, however, because the researchers must first conduct a series of tests to ensure that the new disease-resistance genes will not affect the quality of the taste of cultivated watermelon, according to Fei.

“If you introduce disease-resistant genes into the cultivated plant, the sweetness may become lost. You want to introduce this disease-resistant gene but still make sure the fruit is high quality,” Fei said.

Original Author: Camille Wang