Corn, Other Important Crops Can Now Be Edited by Pollen Carrying CRISPR

The genome editing tool CRISPR has transformed many areas of biology, but using it to enhance crops such as wheat and corn remains difficult because of the plants' tough cell walls. Now, a team of researchers has creatively solved that problem by using pollen from one genetically modified (GM) plant to carry CRISPR's components into another plant's cells.

The researchers used haploid induction, an odd phenomenon which allows pollen to fertilize plants without permanently transferring male genetic material to offspring. The new plants only have a female set of chromosomes, which makes them haploid instead of the traditional diploid. 

The research team used a corn line that can be transformed with CRISPR using bacteria or gene gun technology, and that has a crippled version of a gene, MATRILINEAL, making its pollen able to trigger haploid induction. They then transformed this corn line with a gRNA/Cas9 combinations programmed to target genes related to different desirable traits. The pollen of these transformed plants could then spread the gRNA and Cas9 editing machinery to other corn varieties that had been recalcitrant to CRISPR. 

This haploid induction-edit (HI-edit), as the researchers call the CRISPR pollen method, has only been done in laboratories. However, the researchers say that if it were done in the field, the changes would not spread because the male genome in the pollen disappears shortly after fertilization.

For more details, read the news article in Science.