Expression of cgmpg2, an Endopolygalacturonase Gene of Colletotrichum gloeosporioides f. sp. malvae, in Culture and during Infection of Malva pusilla

A novel polygalacturonase gene was found in the plant pathogenic fungus, Colletotrichum gloeosporioides f. sp. malvae, which causes anthracnose disease of round-leaved mallow (Malva pusilla). Sequence comparisons showed that this gene, cgmpg2, is highly similar to clgpg2, which was previously described from C. lindemuthianum. In culture, expression of cgmpg2 was observed by reverse transcriptase (RT)-polymeraase chain reaction (PCR) with mallow cell wall extract as a sole carbon source and a starting pH of 3.5, but not with this substrate at a starting pH of 7.5 or in media with pectin or glucose as sole carbon sources. The expression of cgmpg2 during infection of mallow leaves was compared with the constitutively expressed actin gene, actA, of C. gloeosporioides f. sp. malvae by co-amplification in RT-PCR. Expression of cgmpg2 was detected in both the biotrophic and necrotrophic phases of infection with the highest expression levels at the early part of the necrotrophic phase