Feeding the world: Uncovering a key regulator of flower head development in rice

April 1, 2016, American Society of Plant Biologists

Rice is a staple food for more than 3.5 billion people worldwide. Meeting the demand for high-yielding rice is an urgent task for breeders. Superior, high-yielding hybrid plants are often produced by crossing two diverse parental lines. This task is quite complicated in rice, a self-pollinating plant. One approach to solving this problem originated in the 1970s, when Chinese scientists figured out how to produce male sterile (MS) rice lines.

The use of MS lines allows breeders to perform controlled pollination, leading to successful hybrid rice production. Unfortunately, in these MS lines, the panicle (flower head) often remains enclosed in the surrounding leaf sheath because the region of the stem that supports it (the uppermost internode) is short, leading to blocked pollination and reduced seed production. To allow panicles to elongate and emerge from the leaf sheath, breeders use rice plants with a mutation in the gene ELONGATED UPPERMOST INTERNODE1 (EUI1), which encodes an enzyme that deactivates the plant hormone gibberellin (GA). This deactivation allows GA to stimulate uppermost internode extension, leading to panicle extension, as well as increased plant height. Understanding what regulates the enzyme EUI1 in normal (wild type) plants is crucial, as according to Dr. Chengcai Chu of the Chinese Academy of Sciences, "A further understanding of the molecular mechanism through which EUI1 activity is regulated during development will provide a more flexible way to fine-tune panicle extension, which may greatly help breeders improve hybrid rice ".

By isolating and exhaustively analyzing a dwarf mutant with impaired panicle extension, Dr. Chu and colleagues uncovered a critical regulator of EUI1 gene expression in , as discussed in this week's issue of The Plant Cell. This regulator, HOX12, binds directly to regulatory elements of the EUI1 gene, functioning as a transcription factor, or central regulator. The scientists propose that HOX12 helps regulate plant growth in response to environmental cues through its effect on EUI1, which acts as a switch to regulate the migration of floral-derived GA from the panicle to the stem. The next step will be to determine the upstream initiators of the HOX12-EUI1 regulatory cascade and the physiological conditions under which these modulations occur.

Explore further: Public rice genomic resources are boon for breeders

More information: Shaopei Gao et al. Rice HOX12 Regulates Panicle Exsertion by Directly Modulating the Expression of ELONGATED UPPERMOST INTERNODE1, The Plant Cell (2016). DOI: 10.1105/tpc.15.01021

Related Stories

Public rice genomic resources are boon for breeders

February 5, 2016

A Cornell-led international team of researchers has launched a set of open-access genomic resources that will greatly accelerate the ability of geneticists and breeders to link genes to important traits in rice.

Less can be more, for plant breeders too

March 19, 2008

Imagine you are a rice breeder and one day within a large field you discover a plant that has just the characteristics you have been looking for. You happily take your special plant to the laboratory where you find out that ...

Finding rice traits that tackle climate-change challenges

December 11, 2014

People around the world depend on food crops adapted to an array of temperature and precipitation regimes, but those conditions are in flux because of global climate change. So scientists want to identify plant traits that ...

Recommended for you

Fish-inspired material changes color using nanocolumns

March 20, 2019

Inspired by the flashing colors of the neon tetra fish, researchers have developed a technique for changing the color of a material by manipulating the orientation of nanostructured columns in the material.


Adjust slider to filter visible comments by rank

Display comments: newest first

not rated yet Apr 01, 2016
I for one am tired of all these agricultural industry/research type people acting like increasing yields is a panacea. It is not. You are just trading one problem for another at best. If you have population pressures the thing not to do is grow more food. (I'm not saying don't feed people) I am saying that people should stop having as many kids. Family planning and education, especially for the females, is the only long term solution that is viable.
not rated yet Apr 02, 2016
"Family planning and education, especially for the females, is the only long term solution that is viable."
Tell that to the Vatican, the Muslims, the Indians, the Chinese...well, around 4 billions plus who are screwing themselves silly once the hormones or religious teachings took hold!

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.