CRISPR Helps Researchers Identify Peptides for Pollen Tube Growth in Rice

Researchers from Pusan National University led by Assistant Professor Yu-Jin Kim from the Department of Life Science and Environmental Biochemistry have identified two rapid alkalinization factor (RALF) peptides in rice and determined their functions in pollen tube germination and growth using CRISPR-Cas9.

The researchers analyzed protein sequences from the Rice Genome Annotation Project database and identified 41 RALF genes. From this number, they identified that OsRALF17 and OsRALF19 were expressed in high amounts in pollen and pollen tubes specifically. Using CRISPR-Cas9, the researchers characterized their corresponding peptides and generated knockout mutants in which one or both pollen-specific RALF genes were not expressed. The lack of OsRALF17 and OsRALF19 expression caused near-total male sterility in rice with defects in pollen hydration, germination, and tube growth, indicating their critical importance in male reproduction and seed production.

The researcher also found that both peptides bind to a protein receptor called Oryza sativa male-gene transfer defective 2 (OsMTD2) and transmit signals via reactive oxygen species, which facilitates pollen tube germination and maintains integrity in rice.

For more details, read the article in Pusan University Research Highlights.