Genes borrowed from bacteria allowed plants to move to land
Natural genetic engineering has allowed plants to move from water to land, according to a new study by an international group of scientists from Canada, China, France, Germany and Russia.
"This is one of the most important events in the evolution of life on this planet, without which we would not exist as a species," said Gane Ka-Shu Wong, co-researcher and professor in the Faculty of Science and the Faculty of Medicine and Dentistry at the University of Alberta. "The movement of life from water to land - called terrestrialisation - began with plants and was followed by animals and then, of course, by humans. This study establishes how this first step took place."
The movement of plants from water to land was made possible when the genes of soil bacteria were transferred to algae through a process called horizontal gene transfer. Unlike vertical gene transfer, such as DNA transfer from a parent to a child, horizontal gene transfer occurs between different species.
Life on land
"For hundreds of millions of years, green algae have lived in periodically drying freshwater environments, such as small puddles, river beds and dripping rocks," says Michael Melkonian, professor at the University of Duisburg-Essen in Germany. "These algae mingled with soil bacteria and received key genes that helped them and their descendants cope with the harsh terrestrial environment and evolve into the terrestrial plant life we see today.
The study is part of an international project focused on sequencing the genomes of more than 10,000 plant species. The discovery was made as part of the sequencing of two particular algae, one of which is a new species (Spirogloea muscicola) introduced into the community by this publication.
"The approach we used, phylogenomics, is a powerful method to identify the underlying molecular mechanism of evolutionary novelty," said Shifeng Cheng, first author and senior researcher at the Agricultural Genome Institute in Shenzhen, Chinese Academy of Agricultural Sciences.
The article, "Genomes of subaerial Zygnematophyceae provide insights into land plant evolution", will be published in Cell on November 14, 2019.
