The researchers explained how plant life originated on Earth

Researcher from University of Copenhagen This explained how plant life originated on the surface of our planet. In particular, they showed that terrestrial plants need two genes to protect themselves from fungal attack – a defense system that is 470 million years old. This resistance paved the way for almost all plant life on earth.

Plants evolved from water algae about half a billion years ago to survive on Earth, which laid the foundation for life on Earth. One of the most difficult obstacles to this dramatic transformation was the fungus:

It is estimated that 100 million years ago, fungi crawled across the earth’s surface in search of food, mostly found in dead algae that flowed from the ocean. So, if you are going to establish yourself in the soil as a new plant, the first thing you encounter is a fungus that eats you, and you need some kind of immune system, ”says Modus Eggert Nielsen, a biologist in the department. Plant and Environmental Sciences at the University of Copenhagen.

According to Madness Eggert Nielsen, a research associate at the Department of Plant and Environmental Sciences and at the University of Paris-Slay, the core of this immune system can be reduced to two genes, PEN1 and SYP122. Together, they help to create a kind of factor that prevents the attack of fungi and fungus-like organisms on plants.

“We found that destroying these two genes in our Arabidopsis model would open the door for pathogenic fungi to penetrate. We found that they are essential for the formation of plug-like cell walls that protect against fungi. Interestingly, it appears to be a universal defense mechanism found in all terrestrial plants, ”said Madeus Egert Nielsen, senior author of the study, published in the journal Science. Life.

I grew up in a factory that is 470 million years old

The research team tested the same activity at Liverwort, a direct successor to one of the first land plants on Earth. By taking two genes that match in the liverworts and inserting them into the crescendo, the researchers tested whether they could determine the same effect. The answer is yes.

Experiment with Arabidopsis Model Credits: Mads Eggert Nielsen

“Although two plant families derived from Arabidopsis and Liverwort evolved in different directions 450 million years ago, they continue to share genetic functions.

Coexistence of plants and fungi

Although fungi are a barrier to the transition from marine algae to terrestrial plants – they are also a precondition. Mads Egert Nielsen explains that once plants are able to survive the onslaught of fungi that want to eat them on Earth, the next problem they face is finding nutrients:

Aquatic plants have easy access to dissolved nutrients such as phosphorus and nitrogen. But 500 million years ago, the earth we know today does not exist – only rock. Rock-related nutrients are very difficult for plants to obtain. But not for mushrooms. Fungi, on the other hand, cannot produce carbohydrates – which is why they are eaten by plants. It is believed that this is where the symbiotic relationship between plants and fungi arose, which later became the basis for the eruption of terrestrial vegetation during this period.

Immune structures formed in plants do not kill the plant or the fungus, preventing them from being attacked by fungi.

“Since the fungus can only partially enter the plant, we believe there will be a tipping point for the plant and the fungus to gain something. Therefore, it is helpful to keep the relationship intact. The theory that plants tame fungi to colonize their soil is not ours, but we feed the animals that support this idea, “said Madeus Egert Nielsen.

Can be applied in agriculture

New discoveries add an important part to the enigma of the evolutionary history of plants. More importantly, they can be used to make crops more resistant to fungal attack, which is a big problem for farmers.

“If all plants are immune in the same way, it means that pathogenic microorganisms – such as powdery mildew, yellow rust and potato rot – have found a way to infiltrate or prevent the resistance of their respective host plants, and we need to know how they do it. We’ll try to pass, so we’ll get the defense, “said Mads Eggert Nielsen.

Modus Egert Nielsen is involved in a research project in the Department of Botanical and Environmental Sciences, led by Hans Thordel-Christensen, and with the support of the Novo Nordisk Foundation, focuses on identifying immune systems in plants that are susceptible to pathogenic microorganisms and making plants more resistant. Overcome. Close.

Additional facts

Researchers have long speculated that the PEN1 and SYP122 genes may play a role in the transformation of plants from algae to terrestrial plants, but there is no clear evidence that they are preconditions for plants. Immunity.

Previous studies have shown that destroying the PEN1 gene can cause plants to lose their ability to fight powdery mildew. However, when the closely related gene, SYP122, was destroyed, nothing happened. The results of a new study show that the two genes together play an important role in plant protection systems.

Reference: “Plant SYP12 structures develop evolutionarily protected general immunity against nematode pathogens” Hector M Rubiato, Mingqi Liu, Richard J O’Connell and Mads E. Nielsen, 4 Feb 2022, available here. Life.
DOI: 10.7554 / eLife.73487