Scientists find genes that help fruit adapt to droughts

As droughts are becoming increasingly frequent due to climate change, scientists are struggling to discover new ways of helping plants to adapt to prolonged water stress. Now, a team of researchers from the Boyce Thompson Institute and Cornell University has provided a comprehensive picture of gene expression changes in response to water stress in the tomato fruit (Solanum lycopersicum), identifying genes which could help plant breeders develop fruits that are more resilient to drought conditions.

“We identified genes that are involved in water stress response in the tomato fruit,” said study senior author Carmen Catalá, an expert in the molecular regulation of fruit formation at Boyce Thompson. “We can now begin to select candidate genes that could help breeders develop fruit that can adapt to drought conditions, and not just tomatoes but also grapes, apples, and fleshy fruit in general. That is a long-term potential application of these data.”

The scientists examined gene expression in tomato leaves and six fruit organs (pericarp, placenta, septum, columella, jelly, and seeds) in both growing and ripe fruit under four different water stress conditions (none, mild, intermediate, and strong). 

The analysis revealed that each of the organ tissues changed in unique ways over time. “Less than one percent of the expressed genes that were affected by water stress were shared among all six fruit tissues, and more than 50 percent of the affected genes were specific to a single tissue,” Catalá explained.

Surprisingly, the experts also identified some positive effects associated with (mild) drought, including an increase in the level of lycopene – an antioxidant with documented health benefits – in ripe fruit, and higher levels of starch biosynthesis, which could yield sweeter tomatoes.

Moreover, the findings suggest that tomatoes could be “trained” to be more resistant to future droughts. “When we sowed the seeds from treated plants, we found that the seedlings from stressed tomatoes showed improved recovery from water stress in comparison to seedlings from control tomatoes,” said study first author Philippe Nicolas, a postdoctoral fellow in Plant Research at Cornell.

The scientists identified several genes whose expression was induced by water stress in mature seeds that could play a crucial role in conferring drought tolerance to the next generation of plants. “The range of genes affected by water stress shows how complex plants can be, and that basic research is critical to identifying ways to make fruits, vegetables and grains more resistant to drought, a vital step in feeding the planet sustainably,” concluded Diane Okamuro, a program director in National Science Foundation’s Division of Integrative Organismal Systems.  

The study is published in the journal Plant Physiology.

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By Andrei Ionescu, Earth.com Staff Writer

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