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ARS Home » Pacific West Area » Pullman, Washington » Grain Legume Genetics Physiology Research » Research » Publications at this Location » Publication #319969
Title: Use of metabolomics for the chemotaxonomy of legume-associated Ascochyta and allied genera

Author
item KIM, WONYONG - Washington State University
item PEEVER, TOBIN - Washington State University
item PARK, JEONG-JIN - Washington State University
item PARK, CHUNG-MIN - Washington State University
item GANG, DAVID - Washington State University
item XIAN, MING - Washington State University
item DAVIDSON, JENNY - South Australian Research And Development Institute
item INFANTINO, ALESSANDRO - Consiglio Nazionale Delle Ricerche
item Chen, Weidong

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/23/2015
Publication Date: 2/5/2016
Citation: Kim, W., Peever, T., Park, J., Park, C., Gang, D., Xian, M., Davidson, J.A., Infantino, A., Chen, W. 2016. Use of metabolomics for the chemotaxonomy of legume-associated Ascochyta and allied genera. Scientific Reports. 6:20192 doi: 10.1038/srep20192.

Interpretive Summary: Accurate identification of plant pathogens is critical not only for devising management strategies, but also for unambiguous communications among plant pathologists and plant health practitioners. The fungal species in the genera Ascochyta and Phoma that causes Ascochyta blight of legume crops cause similar symptoms on host plants, are morphologically similar and produce various kinds of secondary metabolites. Extensive studies have been conducted on morphology and phylogeny based on various DNA sequences, but the secondary metabolites of these pathogens, despite their important ecological roles, have not been explored for their usefulness in fugal taxonomy. Here, we investigated the chemical diversity of legume-associated Ascochyta and Phoma species and the possible use of a metabolomics approach using liquid chromatography-mass spectrometry (LC-MS) for their classification. We found a high degree of intra-species consistency in metabolic profiles, but inter-species diversity was high. Clusters based on similarity of metabolic features were largely congruent with the species phylogeny. These findings suggest that evolutionarily distinct fungal lineages have diversified their metabolic capacities as they have evolved independently. This new approach using whole metabolomics will be an effective tool for polyphasic taxonomy of these and many other fungal taxa.

Technical Abstract: Chemotaxonomy and the comparative analysis of metabolic features of fungi have the potential to provide valuable information relating to ecology and evolution, but have not been fully explored in fungal biology. Here, we investigated the chemical diversity of legume-associated Ascochyta and Phoma species and the possible use of a metabolomics approach using liquid chromatography-mass spectrometry (LC-MS) for their classification. The metabolic features of 45 strains including 11 known species isolated from various legumes were extracted, and the datasets were analyzed using chemometrics methods such as principal component and hierarchical clustering analyses. We found a high degree of intra-species consistency in metabolic profiles, but inter-species diversity was high. Molecular phylogenies of legume-associated Ascochyta/Phoma species were estimated using sequence data from three protein-coding genes and the five major chemical groups that were detected in the hierarchical clustering analysis were mapped to the phylogeny. Clusters based on similarity of metabolic features were largely congruent with the species phylogeny. These results indicated that evolutionarily distinct fungal lineages have diversified their metabolic capacities as they have evolved independently. Chemotaxonomy has not been applied to the genera Ascochyta and Phoma, mainly due to the lack of information on their metabolic content. This whole metabolomics approach may be an effective tool for polyphasic taxonomy of many fungal taxa.