Researchers from the Chinese Academy of Sciences have developed a groundbreaking gene editing strategy for the economically important macroalga Neopyropia, paving the way for its potential use as a model species and enabling molecular design breeding.
Illuminating the Hidden World of Neopyropias
Neopyropia is an economically important macroalga and is one of the most extensively cultivated seaweeds in China, Japan, and South Korea. It is a red algae, and hence, it (the organism) can be considered as a prospective model species for basic research in macroalgae biology. Nevertheless, its intricate genome with a remarkable high GC content and enigmatic gene expression mechanisms have hindered availability of suitable tools for essential gene editing required for genetic breeding and advancement in reverse genetics research.
Now, a study led by Prof. Wang Guang- ce from the Institute of Oceanology of Chinese Academy of Sciences (IOCAS) has made a significant breakthrough on that. Here we demonstrate a gene editing strategy in the economically significant macroalga Neopyropia yezoensis (neopyropia) by exploiting its life history, and design an optimal CRISPR/Cas system for this project.
Multifarious NeoPyropia Gene Editing
To make the gene editing work in Neopyropia, the researchers used a range of techniques. Initially, they functionally coupled the selection marker gene and CRISPR-associated protein 9 (Cas9) through a self-cleaving peptide gene from a porcine virus. This enabled the expression of Cas9 at a high level in hygromycin-resistant strains, an important step for genome editing.
Furthermore, the U6 gene and promoter of Neopyropia was identified and cloned for the first time in this team. RNA polymerase III recognizes U6 gene and initiates transcription of small nuclear RNA. From there, the researchers used this finding to express the guide RNA (gRNA) needed for the CRISPR/Cas system that had just begun to become a powerful tool for gene editing in Neopyropia.
Using these new tools, the researchers successfully knocked out targeted genes in Neopyropia and generated a collection of genome-edited strains that can be applied in breeding programs to breed mutants within this economically important group of red algal crops. Incredibly, the homozygous mutants made up 9.6% of all engineered samples — a huge improvement.
Conclusion
The development of a gene editing toolkit for Neopyropia provides an important resource for reverse genetic research in this economically significant macroalga. These results not only open an important frontier for basic biological studies on macroalgae, as they will assist the development of Neopyropia yezoensis as a model species for such purposes, but also provide a powerful tool for genetic —assisted molecular breeding in N. yezoensis with potential implications to improve biotechnological application within the marine algae industry.
