Genomes of multicellular algal relatives reveal evolutionary clues to plant origins

Genomes of multicellular algal relatives reveal evolutionary clues to plant origins
by Robert Schreiber
Berlin, Germany (SPX) May 06, 2024

Land plants, which dominate our planet's landscape, have developed from simple organisms into complex forms with diverse organs and cell types. This transformation, supported by a vast network of genes, facilitates the intricate shaping of plant structures through various molecular processes.

This significant evolution began with a singular event-plant terrestrialization-when ancestors of modern plants first adapted to terrestrial environments. Within the algae closely related to terrestrial plants, there exists a spectrum of complexity, from unicellular to multicellular filamentous forms. A recent collaborative study, led by the Universities of Gottingen and Nebraska-Lincoln, has produced the first genome sequences of filamentous "star algae" from the genus Zygnema, as detailed in their publication in Nature Genetics.

The study involved sequencing the genomes of four strains of these algae-two from an American culture collection and two preserved at Gottingen University's own Algal Culture Collection (SAG). Over 50 scientists from nine countries employed advanced sequencing technologies to decode the complete DNA sequences, including the full chromosomal structures of these algae-a pioneering achievement for this group.

The comparison of these genomes with those of other plants and algae highlighted a notable abundance of signaling genes and environmental response factors. Dr. Iker Irisarri from the Leibniz Institute for the Analysis of Biodiversity Change commented, "Many of these genes underpin molecular functions critical for the development of multicellular terrestrial plants. It's remarkable to see how these genetic elements, predating land plants by millions of years, have diversified in the ancestors of both plants and algae to form specialized molecular systems."

Professor Jan de Vries from the University of Gottingen added, "This genome data offers an invaluable resource for the plant science community. Our analysis has revealed complex interactions between genes and environmental responses, highlighting developmental plasticity as a crucial trait of land plants."

Research Report:Genomes of multicellular algal sisters to land plants illuminate signaling network evolution