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Münster (upm/ch).
Arabidopsis thaliana seedlings under a microscope. The group on the left is white and appears slightly smaller on average. The seedlings on the right are green.<address>© Minoru Ueda/PNAS; CC BY-NC-ND 4.0</address>
Seedlings with a specific epigenetic histone mark in their genome cope better with elevated salt concentrations than seedlings without this mark. If this mark is specifically mimicked by means of an amino acid substitution, the same effect is observed in the mutant: the seedlings (right) grow better than those without the mark (left).
© Minoru Ueda/PNAS; CC BY-NC-ND 4.0

Researchers discover a mechanism for salt tolerance in plants

New study: A particular chemical mark in the “histone code” is responsible for adaptation to salt stress

Three people wearing white lab coats. A man (on the left) is sitting at a desk in a laboratory or office; there is a monitor to his left behind him. A woman is standing to his right behind him, and another man is standing to his right beside him.<address>© AG Finkemeier</address>
Professor Iris Finkemeier (centre), Dr Jürgen Eirich (right) and Florian Kotnik have made a significant contribution to the current study.
© AG Finkemeier
Due to artificial irrigation and rising temperatures, the concentration of salts (including sodium chloride, or ‘table salt’) is increasing in soils worldwide. This is not only an environmental problem, but also a challenge for agriculture. For example, increased salinity can disrupt the water balance of most plants (known as glycophytes) or even lead to their death, including our crops. Only in coastal regions do plants exist that have developed special salt-tolerance mechanisms. Such plants are known as halophytes. Yet glycophytes are also able to protect themselves against higher salt concentrations and drought to a certain extent. In order to develop resistant crops, it is necessary to understand the various molecular regulatory mechanisms that play a role in response to salt stress. A team led by Professor Iris Finkemeier from the Institute of Plant Biology and Biotechnology at the University of Münster and Professor Motoaki Seki from the RIKEN research institute in Japan has now discovered a previously unknown mechanism.

The researchers investigated the “histone code” and its role in adapting to salt stress in thale cress (Arabidopsis thaliana). Histones are proteins within the genome. They do not carry genetic information but regulate, along with other factors, whether and to what extent information in the DNA is used to produce proteins. This epigenetic control is based on chemical modifications to histones, known as histone marks, which influence the interaction between histones, DNA and regulatory proteins. The researchers discovered a histone mark that is essential for the plant's stress response.

Dr. Minoru Ueda (left) and Dr. Motoaki Seki (right) are collaborators for this study.<address>© Minoru Ueda - RIKEN</address>
Dr. Minoru Ueda (left) and Dr. Motoaki Seki are collaborators for this study.
© Minoru Ueda - RIKEN
In thale cress, the enzyme “HDA19” plays an important role in regulating plant development, metabolism and stress response. The team demonstrated that this enzyme is responsible for removing the newly discovered histone mark, thereby influencing how the plant copes with high salt content. Plants lacking the enzyme are significantly more tolerant to saline soils. In these plants, proteins that are also found in dry seeds (“late embryogenesis abundant (LEA) proteins”) are produced in greater quantities. These proteins help plants adapt to drought. However, these plants grow slightly slower and produce reduced seed yield. These seedlings are well suited for deciphering the molecular basis of control. In addition to various molecular genetic methods, the team used high-resolution mass spectrometry and identified proteins regulated by HDA19.

The project was funded by the German Research Foundation (DFG), the Japan Science and Technology Agency, the RIKEN institute and the Japanese Ministry of Education, Culture, Sports, Science and Technology.

 

Original publication

Florian Kotnik, Minoru Ueda et al. (2026): HDA19-mediated deacetylation of histone H3.3 lysine 27 and 36 regulates plant sensitivity to salt stress. PNAS; 123 (29) e2534315123; DOI: 10.1073/pnas.2534315123

Further information