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ARS Home » Midwest Area » Urbana, Illinois » Soybean/maize Germplasm, Pathology, and Genetics Research » Research » Publications at this Location » Publication #76963
Title: ASSESSMENT OF GENETIC VARIATION AMONG ISOLATES OF FUSARIUM SOLANI THAT CAUSE SOYBEAN SUDDEN DEATH SYNDROME

Author
item ACHENBACH, LAURIE - SOUTHERN ILLINOIS UNIV
item PATRICK, JENNIFER - SOUTHERN ILLINOIS UNIV
item Gray, Lynn

Submitted to: Mycological Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/30/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: Soybean sudden death syndrome (SDS) is a relatively new disease caused by the soil borne fungus Fusarium solani. There is little information available about the genetic variation of different individuals (called isolates) of the fungus that are present in farmers fields. The present work was undertaken to determine just how variable genetically different individuals of the fungus are in different fields and in different geographical regions. Several molecular techniques were used to examine variation in the DNA patterns from ninety five individuals of F. solani that cause SDS. It was found that the SDS causing individuals could be separated into two groups based on DNA patterns and these groups were distinct from other Fusarium species that do not cause soybean SDS. This work will be of use to soybean plant pathologists because it defines the extent of genetic variation present in individuals of the SDS Fusarium fungus. In addition, this work shows that soybean breeders will not have to use a large number of individuals of the SDS fungus for evaluating soybean cultivars for resistance because all individuals of the SDS fungus are genetically similar.

Technical Abstract: Fusarium solani f. sp. phaseoli is the etiological agent of soybean sudden death syndrome (SDS). This form species includes both members that cause SDS and those that do not. Sequencing of the D2 region of the large- subunit (28S) ribosomal DNA of 14 isolates of F. solani f. sp. phaseoli, both SDS and non-SDS isolates, resulted in identical sequences and thus indicated a very low level of genetic variation within the form species. Random amplified polymorphic DNA (RAPD) analysis was used for a genome- wide estimate of genetic variation and was able to resolve two amplitypes of the SDS isolates. As race differences have not been reported for SDS isolates and virulence assays were unable to discern amplitypes, the biological significance of these genetic differences is as yet unknown.