黑料吃瓜资源

When a plant finds itself in too much shade, it redirects its resources to reach for light. Crop yield and root development stall as the plant focuses on growing taller, striving to rise above neighboring plants to access the sun.

Shade avoidance is a vital survival strategy for an organism that depends on photosynthesis鈥攂ut it鈥檚 a problem for farmers, says 黑料吃瓜资源 (CSHL) Assistant Professor Ullas Pedmale. It limits the density at which growers can plant their crops, and thus, limits yields.

鈥淏ecause of crowding, there is a competition for sunlight鈥攕o their option is to grow taller,鈥� says Pedmale. He adds:

鈥淭he plants are putting all this energy to try to grow taller, but now it鈥檚 at the expense of fruits that we depend on, biomass. Then it鈥檚 also at the expense of the roots, so the roots don’t grow.鈥�

Researchers have been studying plants鈥� shade response for decades in hopes of finding ways to help plants flourish at higher densities. Most of that research has focused on changes in stems and leaves, but Pedmale鈥檚 team wanted to know what happens underground when a plant is deprived of light. It鈥檚 an urgent issue because plants without strong root systems are more vulnerable to droughts, flooding, and hurricanes鈥攖hreats that are becoming more common due to climate change.

Using tomato plants and the model plant Arabidopsis, postdoctoral researcher Daniele Rosado and other members of Pedmale鈥檚 team compared the roots of seedlings grown in full unshaded light to the shorter, less developed roots of plants grown in shade. They found that hundreds of genes that plants use to respond to stress were switched on in the shade-grown plants鈥攊ncluding dozens that encode proteins called WRKYs, which regulate gene expression.

To confirm that they limit root growth, Pedmale鈥檚 team engineered plants in which specific WRKY genes remained highly active, regardless of conditions. They found that plants with high levels of certain WRKY proteins grew the same stunted roots seen in shade-grown plants, even when provided with plenty of light. The plant鈥檚 stems, in contrast, grew at a normal rate. In addition, they discovered that the plant hormone ethylene (required for fruit ripening) may also be involved in roots鈥� shade response.

Pedmale hopes that revealing these proteins鈥� role in shade avoidance will help researchers develop better high-yielding plants: plants that can thrive under more crowded conditions, withstand extreme weather, and maybe even reduce global warming by pulling carbon dioxide out of the air and into extensive root systems.

Written by: Jennifer Michalowski, Science Writer | [email protected] | 516-367-8455

Funding

National Science Foundation, National Institutes of Health, S茫o Paulo Research Foundation, Brazilian National Council of Scientific and Technological Development, David and Fanny Luke Fellowship

Citation

Rosado, D., et al., 鈥淲RKY transcription factors and ethylene signaling modify root growth during the shade avoidance response鈥�, Plant Physiology, October 27, 2021. DOI: