The CRISPR-Cas9 complex is able to target genomic sequences of interest
through a recognition site called PAM. As the number of genome's PAM sites
is only to a certain number, other sites cannot be targeted by the
CRISPR-Cas9 complex. This limitation is addressed by a more recently
discovered enzyme called Cas12a or Cpf1, which recognizes a different PAM
than Cas9.

Scientist Lanqin Xia from Chinese Academy of Agricultural Sciences and
colleagues applied the CRISPR-Cas12a complex in rice by targeting genes
OsPDS, which encodes a phytoene desaturase, and OsSBEIIb, which encodes a
starch branching enzyme IIb. The researchers performed
Agrobacterium-mediated genetic transformation to deliver the gene editing
complex and tested the feasibility, efficacy, and multiplexing activity of
the complex. Results showed editing efficiencies 20 to 31 percent in single
targets and 1 to 9 percent in multiple targets. Notably, multiplexing is
applicable using the Cas12a enzyme and larger insertions and deletions are
produced compared with those in Cas9. The applicability of Cas12a may also
be tested in other crops and plant species.

[www.cell.com]