Evaluation of HvPAPhy_a Gene in Barley Using CRISPR-Cas9 and TALENs

Aarhus University's Inger B. Holme and colleagues from various research institutions used TALEN- and CRISPR-Cas9-induced mutations to study the barley phytase gene HvPAPhy_a. The team aimed to validate the PAPhy_a enzyme as the main contributor of the mature grain phytase activity (MGPA), as well as the importance of a promoter region of the gene containing GCN4, Skn1 and the RY elements, known to be involved in gene expression during grain filling.

The results confirm that the barley PAPhy_a enzyme is the main contributor to MGPA since the grains from the knock-out lines exhibited very low MGPA. Lines with mutations in the HvPAPhy_a promoter region GCN4/Skn1/RY also showed significantly reduced MGPA, proving its importance for HvPAPhy_a expression. Mutant grains with very low MPGA showed delayed germination as compared to grains of wild type barley.

Interestingly, lines with deletions located downstream of the promoter motif showed even lower MGPA levels, indicating that the GCN4/SKn1/RY motif is not the only element responsible for the level of PAPhy_a expression during grain maturation.

For more on this study, read the article in Plant Molecular Biology.