A crispr-cas system for a filamentous fungal host cell

A non-naturally occurring or engineered composition comprising a source of a CRISPR-Cas system comprising a guide-polynucleotide and a Cas protein, wherein the guide-polynucleotide comprises a guide-sequence that essentially is the reverse complement of a target-polynucleotide in a host cell and the guide-polynucleotide can direct binding of the Cas protein at the target-polynucleotide in the host cell to form a CRISPR-Cas complex, wherein the guide-sequence is essentially the reverse complement of the (N)y part of a 5′-(N)yPAM-3′ polynucleotide sequence target in the genome of the host cell, wherein y is an integer of 8-30, wherein PAM is a protospacer adjacent motif, wherein the host cell is a eukaryote, which eukaryote is a filamentous fungus, optionally an Aspergillus, a Penicillium, a Rasamsonia or a Mortierella and wherein PAM is optionally a sequence selected from the group consisting of 5′-XGG-3′, 5′-XGGXG-3′, 5′-XXAGAAW-3′, 5′-XXXXGATT-3′, 5′-XXAGAA-3′, 5′-XAAAAC-3′, wherein X can be any nucleotide or analog thereof, optionally X can be any nucleotide;

• and W is A or T.