Diversity of Species Causing Anthracnose in Chayote in Brazil, with a Description of Two New Species in the Complex

Anthracnose caused by species is the most important disease of chayote () in Brazil. The etiology of chayote anthracnose has been assigned to the species , an important plant pathogenic fungus also reported as the causal agent of anthracnose in other cucurbits worldwide. However, there is no recent survey of the species causing anthracnose in chayote in Brazil. In this study, isolates associated with anthracnose on the fruit and leaves of chayote, from various producing regions in Brazil, were collected and identified. Haplotype analysis based on sequences of the β-tubulin genomic region () of 44 isolates was carried out as a first measure of genetic diversity. A subset of 22 isolates were sequenced using the partial sequences of actin (), glyceraldehyde-3-phosphate dehydrogenase (), and the rDNA ITS (ITS) region. Maximum likelihood analysis was performed using the concatenated sequences. The multilocus sequence analysis revealed four previously described species, , , , and and two novel species, named and . All species were able to induce typical symptoms of anthracnose in chayote fruits but varied in their aggressiveness. The species and were the most aggressive, while was the least aggressive. The species was not found to cause chayote anthracnose in Brazil.