She deciphers how tomato roots communicate

Ora Hazak has always been fascinated by plants and is studying the signals that roots send to the rest of the organism. She aims to understand this communication in order to develop climate change-resistant crops.

Ora was just three when her mother first asked her to water the plants. It was a request that kindled a passion that has not ebbed since. She was 15 when she first attempted to cross red and white garden balsam, obtaining a mixture of red, white and pink flowers. Having thus been introduced to the mysteries of genetics, the budding researcher started to record her finds with almost academic rigour in a small notebook.

Today Ora Hazak is head of a plant biology laboratory at the University of Fribourg. She is interested in the molecules that plants produce to carry information from their roots to their leaves. This communication enables them to respond better to environmental hazards such as drought, sunshine or predators. “Understanding these changes could be crucial in helping some plants in the face of the climate change we are currently experiencing,” the scientist predicts. “It’s taking place much faster than past changes, which plants generally had several centuries to adapt to.”

From the shores of Lake Baikal to Tel Aviv

Adapting to new conditions is something that Ora Hazak has experienced herself. Born in Russia on the shores of Lake Baikal, she grew up near Yekaterinburg, on the doorstep of Siberia. She then traded a continental climate for a Mediterranean one, by setting off to study in the Israeli city of Tel Aviv when she was 19. Her family joined her several years later when tracing their Jewish roots. Studying plant biology was a dream come true for the young woman. She tells us, as if it were the most natural thing in the world and something that everyone does, how she added growth hormones to plants that had already been methodically classified and crossed in the living room. And she recalls how she has always had the desire to share her discoveries.

“I would show my little sister my experiments and try to explain them to her in simple language,” she says with a smile. She does something similar today, either by inviting secondary school students to visit her laboratory or by organising a scientific picture competition in her department. Her desire to communicate is also reflected in the way she talks about her research. She never uses acronyms or technical terms without explaining them straight away. When she talks about the Crispr method used to mutate DNA, for example, she describes it as a pair of molecular scissors that can be used to accurately modify an organism’s genetic material. The researcher then describes in detail how this process can be used to deactivate the genes that she wants to study in a plant one by one. It is a highly effective way of understanding what each gene is responsible for, and it is one that Ora Hazak’s team recently used to identify the genes involved in transporting sap from leaves to roots.

How tomatoes can help society

In an experimental greenhouse at Fribourg’s botanical garden, the scientist shows us the impressive difference in stem thickness between modified and non-modified tomato plants. Thanks to the identification of the genes responsible for this, her group can now alter the development of the sap transport system.

“When you study plant genetics, you dream of being able to contribute to society,” the biologist says. “With tomatoes, the results are directly applicable in farming. In Israel, they’re very often used as a model plant, but that’s less common in Switzerland.” After completing her dissertation at Tel Aviv, she obtained a postdoctoral position at the University of Lausanne to develop her work on roots and plant development in 2015. Thus Ora Hazak came to live on the shores of Lake Geneva, accompanied by her children and, of course, a few tomato seeds.

Four years later she obtained an Ambizione grant for young scientists and a COST grant for cooperation in science and technology from the SNSF. These enabled her to set up her own research group at the University of Fribourg in 2019. “It’s an incredible opportunity,” she insists. “I’ve been able to recruit some extremely talented people and launch a number of collaborations, particularly with Agroscope in Valais and with a leading specialist in molecular research in tomatoes based in the United States.”

Nature is teeming with mutant plants

However, while projects involving genetic engineering and exchanging mutant seeds may be commonplace in the scientific community these days, they are an altogether more thorny issue when it comes to agriculture. When the resistance to genetically modified organisms displayed by certain sections of the population is raised, Ora Hazak cuts us short and explains that “A lot of people think nature is pure and scientists have come to disrupt the natural order. But countless mutations are developing spontaneously at any given moment.” She explains how the diversity this creates is what drives evolution and how it enabled previous generations to select seeds that would yield bigger or better flavoured fruit and vegetables. “Besides, the mutations in the genes I’m working on are in domesticated tomatoes! We can use biotechnology to obtain better plants – bigger or more resistant – in a few months instead of in several centuries.”

The researcher insists that there is a huge difference between when genetic engineering was in its infancy, and scientists would sometimes insert an entire gene to pass it from one species to another, and modern molecular scissor methods such as Crispr: “These days you can make specific changes in a precise location within existing genes. That means there’s virtually no difference between a naturally occurring spontaneous mutation and the result of this type of molecular engineering.” The biologist says that today’s mutants are basically “agricultural-type selection accelerated by science.”

Nature and science are also an important part of Ora Hazak’s life outside work. In spring, when she’s not gardening, she sometimes goes for walks with her husband and four children in fields of dandelions that are just beginning to flower. “Often, after a few minutes, I find a huge flower, one that’s bigger than the others. So I tell my children that I’m studying the genes that are responsible for differences like that.” One day, while out for a walk in the forest, she showed them mosses “that started to evolve over 400 million years ago” and asked: “Do you know how long humans have been around for, just so we can compare?” This is how the seeds of curiosity are planted.

The text of this press release, a download image and further information are available on the website of the Swiss National Science Foundation.

Wissenschaftliche Ansprechpartner:

Ora Hazak
Department of Biology
University of Fribourg
Chemin du Musée 10
CH-1700 Fribourg
Phone: +41 26 300 8816
E-mail: ora.hazak@unifr.ch

https://www.snf.ch/en/UNvsz2a1SuINnlAn/news/she-deciphers-how-tomato-roots-communicate