AsianScientist (Dec. 28, 2016) – A team of plant scientists at the Institute for Basic Science’s Center for Plant Aging Research has clarified how plants decide when to flower. Their research was published in the Proceedings of the National Academy of Sciences.
While some animals hibernate, seek refuge or fly to warmer climates during the coldest months of the year, plants are unable to move freely, therefore try to overcome environmental stresses by timing their physiological processes.
“Plants that bloom too early risk unsuccessful reproduction. Therefore, plants have developed an epigenetic mechanism that regulates their flowering timing,” explained Dr. Kim Yun Ju, first and corresponding author of this study.
Epigenetic regulation controls gene expression through chemical modifications of DNA and DNA interacting proteins, without changing the underlying DNA sequence. A particular type of chemical modification called acetylation can be removed by enzymes known as histone deacetylases (HDACs).
In the present study, the team led by Professor June M. Kwak focused on a particular HDAC in the model plant Arabidopsis thaliana called HDA9. This protein is known to regulate several biological processes, such as flowering time, seed dormancy and stress responses.
The team found that plants lacking HDA9 bloomed earlier and had enlarged fruits, indicating that the regulation of the stem cell activity was compromised. Further research showed that HDA9 forms a complex with a protein known to regulate floral stem cells, called POWERDRESS (PWR). The HDA9-PWR complex deacetylates the gene for AGL19, thereby reducing the levels of AGL19 protein that causes early flowering.
“PWR, HDA9 and AGL19 regulate flowering time. A plant with reduced PWR and HDA9 has increased AGL19 levels and flowers earlier,” explains Kim. “The opposite situation, that is the overexpression of PWR and HDA9, has not been tested yet.”
The next challenge for the team is to study other epigenetic modifications on plant histones and clarify how these different chemical modifications work together to regulate flowering.
The article can be found at: Kim et al. (2016) POWERDRESS and HDA9 interact and Promote Histone H3 Deacetylation at Specific Genomic Sites in Arabidopsis.
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Source: Institute for Basic Science.
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