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Title: APPLICATION OF AMPLIFIED FRAGMENT LENGTH POLYMORPHISM (AFLP) FOR GENETIC CHARACTERIZATION OF COLLETOTRICHUM PATHOGENS OF ALFALFA (MEDICAGO SATIVA)

Author
item Oneill, Nichole
item Van Berkum, Peter
item LIN, JLY-JHU - LIFE TECHNOLOGY, INC.
item KUO, JONATHAN - LIFE TECHNOLOGY, INC.
item UDE, GEORGE - UNIVERSITY OF MARYLAND
item KENWORTHY, WILLIAM - UNIVERSITY OF MARYLAND
item Saunders, James

Submitted to: Phytopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/8/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: Fungal species are usually identified based on the morphology of the fungus, spore size and shape, colony morphology, and the ability of the fungus to infect selected hosts. These techniques are not capable of distinguishing some closely related fungi which have different plant pathogenic properties. Recently a new type of DNA fingerprinting technique has been developed which has significant advantages over the procedures used in the past. This new procedure termed AFLP DNA analysis was been applied to 23 different fungal isolates within the genus Colletotrichum to determine if it can be used to determine the taxonomic relationship in this group. Although to the best of our knowledge AFLP DNA analysis has never been attempted before with phytopathogenic fungi, we found that they were very effective in establishing taxonomic relationships in this group. The analysis was particularly useful in identifying two fungal isolates as belonging to species of the Colletotrichum genus even though definitive determinations were not possible based on morphology. This manuscript demonstrates that AFLP DNA analysis of fungal tissues to establish taxonomic relationships well be a very useful tool in the future for plant pathologists.

Technical Abstract: AFLP, a novel PCR-based DNA analysis technique, was used to assess the level of genomic variation among species and isolates of the genus Colletotrichum, and to characterize two alfalfa pathogens unusually aggressive to anthracnose-resistant alfalfa cultivars. Complex AFLP patterns were obtained using three different primer pairs and genomic similarity analyses derived from qualitative data enabled us to identify two Colletotrichum isolates whose taxa had been uncertain based on morphological criteria. These are C. trifolii (isolate Arl-NW) and C. gloeosporioides (isolate 57RR). The similarity matrices generated by each of the three primer pairs were highly correlated and were combined to determine the genetic relationships among the fungal species and isolates. The genetic diversity detected among and within Colletotrichum species from alfalfa and other crops corroborated morphology, rDNA, and RAPD based taxonomy. AFLP fingerprinting represents a advance in fungal DNA fingerprinting because of the greater resolution and the collection of more information than is possible by RAPD and RFLP techniques. AFLP analysis will be useful in the identification of individual isolates within complex genera such as Colletotrichum.