Scientists have figured out how plants respond to light and can promote food growth by changing genetic switches. This discovery can help increase the food supply for a growing population when agricultural opportunities are declining.
The gene switch study, led by the University of California, Riverside, is now published in Nature Communications.
Almost every aspect of plant growth and development is affected by light. Plants can sense light and temperature through a protein called phytochrome b, which transmits light information into cells, thereby changing the expression of the genome and changing plant growth. However, phytochrome B cannot directly interact with the DNA of plants. To this end, plant cells rely on a family of eight proteins called PIFs.
"The activity of these pifs is directly controlled by phytochromes," said Meng Chen, the lead author of the study and professor of botany at UCR. In addition to controlling the number of PIFs accumulated in plant cells, scientists have learned that when phytochrome B is activated by light, it inhibits the activity of PIFs.
"PIFS is like the chefs in a restaurant. You can adjust the number of them. For example, cutting in half will reduce the productivity of the restaurant." "Or, you can keep all the chefs—in our case, pif—but restrain their hands and feet. This will also slow down their work. This is what we are going to say."
Scientists have also discovered another key component of the plant's response to light. Pif has two parts; one is the part that binds to genes, and the other is the part that activates genes, which tell plants to perform different functions, such as growth or flowering. This study found the precise location of these activation areas—this is the first time this study has been conducted in plant cells.
To find this activation area, Chen's team cut the protein into many small pieces. Then, they checked whether any fragments could activate the gene, and found that one of them was. In order to understand more details, the scientists changed the amino acids on PIF. They believed that the activation area is on PIF and observed how plants respond. This allowed them to determine the location of the gene activation region and how it was constructed.
Chen said: "This method surprised us to discover the similarity between this part of PIF in plants and the tumor suppressor protein in humans." In fact, Professor Chen said that the basic genes of plant, yeast and animal cells are activated. The mechanism has significant similarities.
"Plants, animals, and fungi (such as baker's yeast) all evolved from a common ancestor," Chen said. "Before the differentiation of plants, animals, and fungi, the genetic information in DNA will be converted into RNA and converted into proteins, and this basic function is preserved in the three kingdoms of life through these gene activators."
One of the biggest reasons to study the functions of these cells is to manipulate them. In this case, this discovery could allow scientists to switch genes related to light and temperature on or off, benefiting crop growers.
Part of the strategy for increasing crop yields is to plant more plants per acre. Currently, if you put crops too close together, plants can "see" competing neighbors through their shadows. The plant will then use more energy to grow taller toward the sun, but not necessarily to maximize leaf growth and seed production.
Or, if plants can ignore their neighbors and focus on the production of leaves and seeds instead of growing taller, growers can increase production on the same area.
"You want not only stem growth, but also yield," Chen said. Therefore, plants need energy to make leaves so that they can increase photosynthesis, the process of using sunlight to make food. You want the right part of the plant to grow. "
Chen's team demonstrated that by reducing the activity of the PIF protein, they can slow the growth of stems. Therefore, this research reveals a precise method to make plants grow shorter, so that the seeds, fruits, and edible parts of the plant can grow even in the shade.
"Now we know how plants turn genes on and off based on changes in light and temperature," Chen said. "This is the first step in controlling their response to light and temperature, making them more tolerant of different and sometimes challenging environments in a changing climate."
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