Antagonistic genes modify rice plant growth

Date:
August 26, 2020
Source:
Nagoya University
Summary:
Rice stems lengthen when a newly identified gene activates
during flooding. Another gene suppresses lengthening in shorter
varieties. The insight could help plant breeders.



FULL STORY ========================================================================== Scientists at Nagoya University and colleagues in Japan have identified
two antagonistic genes involved in rice plant stem growth. Their findings, published in the journal Nature, could lead to new ways for genetically modifying rice crops.


========================================================================== Longer, deepwater rice crops are planted in South Asia and West Africa
to survive floods. Shorter paddy rice varieties are widely cultivated
worldwide because they are easier to harvest.

A key driver of plant growth is a hormone called gibberellic acid. It
activates cell division in the stem tissue, causing the stem to
lengthen. Breeders know they can control plant height by stimulating or inhibiting gibberellic acid activity. However, exactly how this works
has been unclear.

Bioscientist Motoyuki Ashikari has been studying the growth and evolution
of rice for years. He and a team of researchers conducted genetic
studies and identified two genes that are involved in regulating rice
plant growth.

"We showed that gibberellic acid is necessary, but not enough, for stem elongation," says Ashikari.

Interestingly, the two genes, called ACCELERATOR OF INTERNODE ELONGATION 1 (ACE1) and DECELERATOR OF INTERNODE ELONGATION 1 (DEC1), counteract each
other as part of the regulation process.

In the presence of gibberellic acid, ACE1 stimulates cell division and elongation of the stem's 'internode' sections in deepwater rice. The
shorter paddy rice variety did not have a functional ACE1 gene, but it
did have a homologous ACE1-like gene that was switched on to activate
stem elongation at a different point of plant development.

DEC1 was found in both the deepwater and paddy rice varieties. Its
expression was reduced when deepwater rice plants were placed in deep
water or treated with gibberellic acid. However, DEC1 continued to be
expressed in paddy rice, even under the same conditions, suggesting this
gene helps to suppress stem growth.

"We also found that ACE1 and DEC1 are conserved and functional in other
plant species, like barley and other grasses, so our investigations
improve understanding of the regulation of stem elongation in members of
the Gramineae family that may have similar stem elongation mechanisms,"
says Ashikari.

The team next aims to understand stem elongation at the molecular level
by identifying factors that are associated with ACE1 and DEC1 expression.


========================================================================== Story Source: Materials provided by Nagoya_University. Note: Content
may be edited for style and length.


========================================================================== Journal Reference:
1. Keisuke Nagai, Yoshinao Mori, Shin Ishikawa, Tomoyuki Furuta, Rico
Gamuyao, Yoko Niimi, Tokunori Hobo, Moyuri Fukuda, Mikiko Kojima,
Yumiko Takebayashi, Atsushi Fukushima, Yasuyo Himuro, Masatomo
Kobayashi, Wataru Ackley, Hiroshi Hisano, Kazuhiro Sato, Aya
Yoshida, Jianzhong Wu, Hitoshi Sakakibara, Yutaka Sato, Hiroyuki
Tsuji, Takashi Akagi, Motoyuki Ashikari. Antagonistic regulation of
the gibberellic acid response during stem growth in rice. Nature,
2020; 584 (7819): 109 DOI: 10.1038/s41586- 020-2501-8 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/08/200826083014.htm

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