The oceans use gene editing technology to obtain high-quality insect-resistant new germplasm of economic microalgae

Recently, the algae physiological process and precision design breeding research team of the Institute of Oceanography of the Chinese Academy of Sciences has made new progress in the research of gene editing technology to create new germplasm, and obtained a new germplasm of marine diatoms with insect resistance and high oil content, Phaeodactylum tricornutum, and the relevant research results were published in Biotechnology for Biofuels and Bioproducts, a top journal in the field of international biotechnology
。 At the same time, the team used gene editing technology to knock out the cryptocyanidin gene of Triangular Brown Finger to obtain a new germplasm with high fucoxanthin content, which was recently published
in the algal journal Algal Research.

Triangular brown finger algae is an important economic microalgae, not only as an important aquatic food, but also as a raw material
for high-value products.
However, protozoan contamination has become a major limiting factor
for large-scale farming of Triangulodontos.
Therefore, it is imperative to cultivate new germplasm of high-quality insect-resistant triangular brown finger algae
.

After years of hard work, the algae physiological process and precision design breeding team discovered a new gene in Triangular Brown Finger (Pt2015) (Figure 1).

The team used CRISPR/Cas9 gene editing technology to knock out Pt2015 and found that the knockout algae strain of Pt2015 was not significantly different
from the wild type in cell morphology and growth rate.
The team found that overexpression of Pt2015 could lead to the transformation of cell morphology from fusiform to three-out radial with special spatial structure, indicating that Pt2015 protein is a positive trigger for the transition of spindle to three-out radial in triangular brown finger cells
.
The study also found that the economic traits of the three-emerge radial algae strain caused by Pt2015 overexpression were extremely stable
.
The Pt2015 overexpressed algae showed a three-out radial pattern, showed obvious resistance to the main predator (amoeba) (2-fold enhanced), and the total intracellular fat content was about 30% higher than that of wild type (Figure 2), and the growth rate was no different
from that of wild type.
The discovery of this gene and the acquisition of knockout and overexpression algae strains will not only help us to understand the morphological transformation mechanism of diatom cells, but also provide a new germplasm
with high oil content and strong insect resistance for large-scale cultivation of Triangulodon.

Triangular brown finger algae is also rich in active substances such as EPA, DHA and fucoxanthin, among which fucoxanthin has anti-tumor, anti-inflammatory, antioxidant, weight loss and other effects, and has become a "star product"
in the marine industry.
In the past, fucoxanthin was mainly extracted from macrobrown algae, but the yield was low and the quality was poor
.
At present, Triangulodonna has become an important raw material
for the extraction of fucoxanthin.
The algae physiological process and precision design breeding team used gene editing technology to knock out the cryptocyanidin gene (CryP) gene of Triangula triangular brown finger, and the fucoxanthin content of mutant algae strains increased significantly (Figure 3).

This research result will provide alternative economic algae strains
for fucoxanthin-related industries.

Fig.
1 Cell localization of Pt2015 protein in Triangulodontomyce

Fig.
2 Microscopic and scanning electron microscopy images of WT(A), Pt2015 knockout (B) and overexpression (C) algae strains and Bodipy505/515 staining (G)

Fig.
3 Cryptocyanidin gene knockout algae strains of Triangulodontomycea

The first authors of the research paper published in Biotechnology for Biofuels and Bioproducts are Associate Professor Gao Shan and Dr.
Lu Zhou, and the corresponding author is Researcher
Guangce Wang.
The first author of the research paper published in Algal Research is Master student Yang Wenting, and the corresponding authors are Associate Professor Gao Shan and Researcher
Wang Guangce.
The research has been supported
by the National Key R&D Program, the Key R&D Program of Shandong Province, the National Algae Industry Technology System and the National Natural Science Foundation of China.