(ORDO NEWS) — Scientists from China analyzed the genomes of representatives of the main groups of land plants and algae and found two main episodes of gene transfer from microorganisms to plants.
These genes, derived from bacteria, fungi, and viruses, may have driven plant evolution hundreds of millions of years ago, giving them features and traits that favor terrestrial life.
Horizontal gene transfer (HGT) is the process of transferring genetic material between organisms of different species. Many microorganisms use HGT for evolution and adaptation to unfavorable external conditions. Thus, it is this process that is responsible for the rapid spread of antibiotic resistance in bacteria.
However, the role of HGT in complex multicellular eukaryotic organisms, including plants and animals, remains controversial and poorly understood. That is why researchers from China have conducted a comprehensive systematic analysis of acquired genes for the main groups of land plants and charophytes (algae).
“Our study changes the traditional view of the evolution of terrestrial plants,” comments Jinling Huang ( Scientists have discovered gene transfer between plants and insects ), the author of the work, a biologist from the University of East Carolina (USA), and a fellow at Henan University and the Kunming Institute of Botany (China) . “I suspected that horizontal gene transfer helped plants move from water to land, but until now we didn’t know how big a role it plays.”
Usually, the genes of complex eukaryotic organisms are transmitted only through vertical gene transfer – from parents to offspring.
At the same time, mutations can occur in individual genes, leading to the appearance of new features and properties. But Huang and his colleagues, including plant biologist Chun-Peng Song of Henan University, have found evidence in previous studies that HGT may be common in plants.
Brief diagram showing the number of horizontal gene transfer events in 12 representative species of charophytes and land plants. (A) The numbers in the ovals represent the gene families passed down to the ancestors of the individual groups, and the numbers in the squares represent the gene families passed down to the species in the sample
To study the role of HGT in plant evolution, the researchers examined the genomes of 31 species from all major plant groups, including mosses, ferns, grasses, nightshades, seed plants, and charophytes. The latter are a department of green plants related to modern terrestrial higher plants and green algae (lower plants).
After analyzing the genomes, Chinese scientists found that almost 600 gene families of modern plants – many more than thought – were derived from PIP. These are mainly genes acquired from bacteria and fungi, but viral sequences are also found.
In addition, the team identified two major episodes of HGT in the evolutionary history of charophytes and the origin of land plants, when more than a hundred gene families passed from microorganisms to plants.
Many of the acquired genes are involved in important biological functions in plants: stress responses, transport of ions and metabolites, growth, development, and metabolism.
“Our discovery suggests that HGT plays a significant role in the evolution of land plants. Compared to mutations due to vertical gene transfer, HGT allows plants to quickly acquire new traits, and some of these new traits can help plants adapt to completely different environments, such as when they moved from water to land,” Huang concluded.
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