A novel actin-related protein gene of Colletotrichum gloeosporioides f. sp. malvae shows altered expression corresponding with spore production.

A novel actin-related protein (arp) was found in the plant pathogenic fungus, Colletotrichum gloeosporioides f. sp. malvae (Cgm), which causes anthracnose disease of round-leaved mallow (Malva pusilla). Sequence comparisons showed that this gene, arpA, belongs to the highly divergent 'other arps' category in the current arp classification system. ArpA is most similar to the arp11 gene of Mus musculus but has a unique structure with deletions at the C-terminus similar to that of the arp10 gene of Saccharomyces cerevisiae. A portion of another putative arp gene, arpB, was found immediately downstream of arpA. Expression of arpA was compared to the constitutively expressed Cgm actin gene, actA. In culture, the relative expression of arpA increased when growth conditions favored sporulation. During infection, arpA expression was greatest at the late necrotrophic phase, when sporulation occurred. Arps have been shown to be important in nuclear migration in fungal hyphae, and the expression pattern of arpA indicates that it may have a particular role during sporulation.