New insights into the evolution and structure of Colletotrichum plant-like subtilisins (CPLSs).

The Colletotrichum plant-like subtilisins (CPLSs) are a family of proteins found only in species of the phytopathogenic fungus Colletotrichum. CPLSs have high similarity to plant subtilisins and our previous work has shown that they were acquired by an ancient horizontal gene transfer event from plants. The rapid growth of sequence data in public databases enabled us to reexamine the structure and evolution of the CPLSs. A new plant subtilisin structural model aided us in refining the tertiary structure of CPLSs. Also, new information about protein interactions of plant subtilisin has provided new insights into the putative function of CPLSs. The availability of new genome sequences of members of the genus Colletotrichum gave us the opportunity to further validate our hypothesis that the CPLSs are unique to the Colletotrichum lineage. Together, this information furthers our knowledge of the potential role of the CPLSs in pathogenicity and the role of HGT in the genome evolution of plant pathogenic fungi.