Biologists at the University of Utrecht have described a new molecular mechanism that allows plants to optimize their growth under suboptimal high-temperature conditions.

The study offers promising clues for the development of climate-tolerant crops, which maintain high yields under stressful high ambient temperatures, according to research leader Martijn van Zanten. They published their findings on November 25 in PNAS.

Many crops suffer from high temperatures and each increase in temperature in degrees Celsius can lead to a loss of up to 10 percent. This is a major problem in the context of current global warming and increasing demands for food. However, many species of plants can adjust the shape of their stems and leaves, making them more resistant to high temperatures. This process is called thermomorphogenesis and leads to an "open-body plan", which allows for efficient evaporation, reduction of direct heat radiation from the sun, and allows heat dissipation by improving air circulation around the leaves. Thermomorphogenesis facilitates cooling and allows the plant to maintain optimal growth and production under suboptimal ambient temperatures,

Thermotolerant crops 

The development of thermotolerant crops requires detailed knowledge of how plants perceive high temperatures and how they translate this signal into growth adjustments. "However, it is still not well understood how plants detect temperature and what molecular factors contribute to thermomorphogenesis," explains late author Martijn van Zanten from Utrecht University, who led the international team of researchers from Utrecht, UK. Kingdom, Italy, Sweden and Czech Republic. Republic, Australia and Wageningen. 'We discovered an unknown molecular mechanism by which plants control thermomorphogenesis, especially in young seedlings, the most sensitive period in plant life when it comes to ambient temperature. These new pieces of the puzzle can make the development of future thermotolerant crops more efficient. 

In the journal PNAS, researchers demonstrated on November 25 that the enzyme histone deacetylase 9 (HDA9) plays a key role in thermomorphogenesis in the widely used model plant Arabidopsis thaliana. At increasing temperatures, the abundance of the enzyme increases, resulting in the removal of epigenetic modifications of DNA-bound histone proteins that have an inhibitory effect on the synthesis of the well-known plant growth hormone auxin. As a result, auxin levels rise and the plant adjusts its height.

Plant growth 

"This new mechanism is scientifically very interesting, because it shows that a histone deacetylase 9 has an indirect positive effect on transcription, while histone deacetylases are generally accepted as suppressors of this process," says Van Zanten. 'Furthermore, we showed that HDA9 works independently of the only known temperature sensor, Phytochrome B, which is also a light sensor. By doing so, we are exposing a new temperature signaling pathway in plants.

According to the researchers, this finding offers interesting application possibilities. 'We show that HDA9 mutants are impaired in the ability to adjust their body plan at high temperatures, but can still react normally to light signals from neighboring plants in dense vegetation. With this knowledge in hand, we can now decouple the light-controlled plant growth from temperature-controlled settings, "says Van Zanten. Therefore, this research offers interesting starting points for the development of climate-tolerant crops, without compromising other desirable properties.

Source:  https://mundoagropecuario.com/