Featured Research

from universities, journals, and other organizations

Seed size is controlled by maternally produced small RNAs, scientists find

Date:
April 11, 2012
Source:
University of Texas at Austin
Summary:
Seed size is controlled by small RNA molecules inherited from a plant's mother, a discovery that has implications for agriculture and understanding plant evolution.

Small RNAs affect development of seeds. Arabidopsis seeds 3, 4, 5, 6 and 7 days (left to right) after pollination. Seeds in the second row are from a cross between a diploid mother and tetraploid father. Seeds in the third row are from a cross between a tetraploid mother and diploid father. Seeds in the third row (5 to 6 days after pollination) are much smaller as a result of increased maternally inherited small RNAs.
Credit: Image courtesy of University of Texas at Austin

Seed size is controlled by small RNA molecules inherited from a plant's mother, a discovery from scientists at The University of Texas at Austin that has implications for agriculture and understanding plant evolution.

"Crop seeds provide nearly 70 to 80 percent of calories and 60 to 70 percent of all proteins consumed by the human population," said Z. Jeff Chen, the D.J. Sibley Centennial Professor in Plant Molecular Genetics at The University of Texas at Austin. "Seed production is obviously very important for agriculture and plant evolution."

Chen and his colleagues, including David Baulcombe at the University of Cambridge, provide the first genetic evidence that seed development is controlled by maternally inherited "small interfering RNAs," or siRNAs.

They published their research April 3 in the journal PNAS.

SiRNAs are known to control a number of aspects of growth and development in plants and animals. The researchers used Arabidopsis, a rapidly growing flowering plant in the mustard family, for the study.

In this case, the researchers found that the siRNAs influence the development of a seed's endosperm, which is the part of the seed that provides nutrients to the developing plant embryo, much like the placenta in mammals. The endosperm is also the source for most of the nutritional content of the seed for humans and animals.

Despite the importance of the endosperm, little has been known about the molecular mechanisms that govern its growth.

In flowering plant seeds, the embryo is formed by fusion of one paternal and one maternal genome, while the endosperm combines one paternal and two maternal genomes. This process of embryo and endosperm formation is known as "double fertilization."

The scientists found that when a female plant with a duplicate genome (known as a tetraploid) is crossed with a male plant with a normal genome (called a diploid), not only is there an increase in the maternal genome in their offspring's seed endosperm, but there is also an associated increase in maternal siRNAs.

Those maternal siRNAs decrease the expression of genes that lead to larger endosperm growth, meaning that the siRNAs create smaller seeds.

"Now we understand that siRNAs play a large role in sensing maternal and paternal genome imbalance and controlling seed development, and that maternal control is important," said Chen.

The researchers are working to find out how exactly siRNAs regulate gene expression in the endosperm and embryo and how they control seed size. These new findings will enable scientists to develop biotechnological tools for improving seed production and crop yield.

But Chen cautioned that "bigger isn't always better." In fact, in his experiments, seeds lacking the control of the maternally inherited siRNAs grew so large that they collapsed.

Chen's research is funded by the National Science Foundation Genetic Mechanisms program. It was also the result of a Fulbright Award he received to do research with Baulcombe, a Royal Society research professor, at Cambridge. Baulcombe is widely recognized for his pioneering and seminal research discovering the role of siRNAs in gene silencing in plants.


Story Source:

The above story is based on materials provided by University of Texas at Austin. Note: Materials may be edited for content and length.


Journal Reference:

  1. J. Lu, C. Zhang, D. C. Baulcombe, Z. J. Chen. Maternal siRNAs as regulators of parental genome imbalance and gene expression in endosperm of Arabidopsis seeds. Proceedings of the National Academy of Sciences, 2012; 109 (14): 5529 DOI: 10.1073/pnas.1203094109

Cite This Page:

University of Texas at Austin. "Seed size is controlled by maternally produced small RNAs, scientists find." ScienceDaily. ScienceDaily, 11 April 2012. <www.sciencedaily.com/releases/2012/04/120411132214.htm>.
University of Texas at Austin. (2012, April 11). Seed size is controlled by maternally produced small RNAs, scientists find. ScienceDaily. Retrieved July 30, 2014 from www.sciencedaily.com/releases/2012/04/120411132214.htm
University of Texas at Austin. "Seed size is controlled by maternally produced small RNAs, scientists find." ScienceDaily. www.sciencedaily.com/releases/2012/04/120411132214.htm (accessed July 30, 2014).

Share This




More Plants & Animals News

Wednesday, July 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Otters Enjoy Water Slides at Japan Zoo

Raw: Otters Enjoy Water Slides at Japan Zoo

AP (July 30, 2014) River otters were hitting the water slides to beat the summer heatwave on Wednesday at Ichikawa City's Zoological and Botanical Garden. (July 30) Video provided by AP
Powered by NewsLook.com
In Virginia, the Rise of a New Space Coast

In Virginia, the Rise of a New Space Coast

AP (July 30, 2014) Every summer, tourists make the pilgrimage to Chincoteague Island, Va. to see wild ponies cross the Assateague Channel. But, it's the rockets sending to supplies to the International Space Station that are making this a year-round destination. (July 30) Video provided by AP
Powered by NewsLook.com
Rodents Rampant in Gardens Around Louvre

Rodents Rampant in Gardens Around Louvre

AP (July 29, 2014) Food scraps and other items left on the grounds by picnickers brings unwelcome visitors to the grounds of the world famous and popular Louvre Museum in Paris. (July 29) Video provided by AP
Powered by NewsLook.com
Jane Goodall Warns Great Apes Face Extinction

Jane Goodall Warns Great Apes Face Extinction

AFP (July 29, 2014) The world's great apes face extinction within decades, renowned chimpanzee expert Jane Goodall warned Tuesday in a call to arms to ensure man's closest relatives are not wiped out. Duration: 00:58 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins