Discovery Gives Insight into How Seeds Germinate in Response to Light

September 26, 2019 • by Esther Robards-Forbes
Seedling with roots exposed

Biologists at the University of Texas at Austin have discovered one of the key processes that let plants know when the time is right to grow and develop from seeds. The findings, published in Nature Communications, could enable future advances to improve crop yields and develop plants that can withstand a changing climate or even grow in the shade.

In the recent paper, Enamul Huq, professor of molecular biosciences, along with researchers and students in the Huq Lab, discovered a biochemical mechanism that was not well understood before and that shifts the previous understanding about how plants sense light and how light triggers plant growth.

Plants sense and adapt in response to light using photoreceptors. Phytochromes, the type of photoreceptor the Huq Lab focuses on, respond to the red/far-red part of the light spectrum. The new study outlines the biochemical mechanism by which a phytochrome interacts with an enzyme complex that triggers early light-induced protein modifications within the plant which controls the decision to initiate seed germination or not.

"Overall, this study provides insight into how photoreceptors, and phytochromes specifically, regulate plant growth and development," Huq said. "Light is not only a source of energy for plants, it is also information—a signal. Using their photoreceptors, plants can tell how far they are from one another, how much light they are getting, what direction it's coming from, the length of the days and what season it is."

By isolating a specific signaling mechanism between phytochromes and a specific enzyme complex that is required for the early light-induced protein modifications, Huq and his team have unlocked a key novel function of a previously known factor that determines germination.

"The practical application of these fundamental understandings has great potential. The new knowledge can help produce plant varieties that can grow more efficiently," Huq said.

"This discovery allows for more fine-tuned tinkering," Huq said. "We can tailor the plants to our needs. Right now, we're losing certain growing areas because of climate change. Instead of moving crops to new areas, if we can keep using existing growing areas and get more yield from them, that's a huge benefit."

Inyup Paik, Fulu Chen, Vinh Ngoc Pham, Ling Zhu and Jeong-Il Kim also contributed to the research while working in the Huq Lab. Funding for the research was provided by grants from the National Institutes of Health, the National Science Foundation, and the Rural Development Administration of the Republic of Korea. The authors acknowledge the Texas Advanced Computing Center (TACC) at The University of Texas at Austin for providing high-performance computing, visualization, and database resources that have contributed to the research results.