Submitted to: Mycologia
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/13/2013
Publication Date: 1/1/2014
Publication URL: http://handle.nal.usda.gov/10113/58982
Citation: Yang, H., Haudenshield, J.S., Hartman, G.L. 2014. Colletotrichum incanum sp. nov., a curved-conidial species causing soybean anthracnose in USA. Mycologia. 106(1):32-42. DOI: 10.3852/13-013. Interpretive Summary: Anthracnose of soybean was first reported in Korea in 1917, and now is known to occur wherever the crop is grown. The disease has been reported to cause yield losses in southern areas of the USA. The most common pathogen that causes soybean anthracnose is Colletotrichum truncatum. In 2009, a survey of the distribution of Colletotrichum species in soybean fields in Illinois was conducted by collecting soybean stems and petioles with anthracnose symptoms from soybean fields. The characterization of Colletotrichum species was based on traditional morphological observation plus multi-gene sequence phylogenetic analyses. Multi-gene sequence phylogenic analyses revealed a genetically distinct species from other established Colletotrichum species. One isolate from this group was examined closely for its morphology, cultural characteristics, and pathogenicity on soybean. The result based on the molecular phylogenetic and the morphological and pathogenicity analyses, indicated that we had discovered a new species of Colletotrichum. This information is important to mycologists, soybean pathologists and others interested in fungi that attack plants and specifically those that attack soybean.
Technical Abstract: Soybean anthracnose is caused by a number of species of Colletotrichum that as a group represent an important disease that results in significant economic losses. In the present study, Colletotrichum species were isolated from soybean petioles and stems with anthracnose symptoms from soybean fields in Illinois. Multi-gene sequence phylogenic analyses, combining rDNA internal transcribed spacer (ITS), actin (ACT), ß-tubulin (TUB2), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and histone H3 (HIS3) gene regions, revealed a genetically distinct species from other established Colletotrichum species. One isolate from this group was examined closely for its morphology, cultural characteristics, and pathogenicity on soybean. As a result of the molecular phylogenetic, morphological and pathogenicity analyses, we hereby introduce the new Colletotrichum species as Colletotrichum maxi.