The Ulva prolifera genome reveals the mechanism of green tides

The genome of green microalgae has rarely been reported. Ulva prolifera is a green microalga that has received much attention. Despite research articles about U. prolifera in recent years, we know very little about its genome. Therefore, the 87.9-Mb haploid genome (containing 10 311 protein-coding genes) of U. prolifera was studied, and the genome was compared with that of U. mutabilis, which is the only published Ulva species. Results showed that the two species are closely related. A phylogenetic tree was constructed among U. prolifera and other green algae available in GenBank, revealing the evolutionary status of U. prolifera in Chlorophyta. To understand why U. prolifera could grow rapidly, we identified some genes related to growth, such as those involved in cell division, phosphorylation, and cell proliferation. In addition, genes related to stress resistance were found, which supports the notion that U. prolifera grows vigorously in nature. These results help to characterize green tides from a new perspective and reveal some important insight into the biology of U. prolifera.