Seamless deletion of a large DNA fragment in the taxol-producing fungus Pestalotiopsis microspora

To reduce the unnecessary gene clusters in the taxol-producing fungus Pestalotiopsis microspora, we report the development of an effective DNA deletion method that relies on a deletion cassette constructed with the Gateway-technique and overlap extension PCR, using the orotidine 5′-phosphate decarboxylase as recyclable marker for selection. By this approach, two adjacent DNA sequences can be sequentially deleted in a single transformation mediated by Agrobacterium tumefaciens, resulting in the deletion of a large DNA fragment. Additionally, the selection marker is spontaneously eliminated in this process. We used this method to successfully remove the mus53 locus of P. microspora.