Submitted to: Molecular Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/1/1996
Publication Date: N/A
Interpretive Summary: The rice water weevil (RWW) is the major insect pest of rice in Louisiana. The pesticide currently used to control the RWW has been banned by the Environmental Protection Agency. Therefore, alternative strategies to control the RWW are being examined including the use of a fungus, Beauveria bassiana, which is capable of killing the insect. A number of B. bassiana isolates have been recovered from infected RWW and soil samples at the Ric Research Station in southern Louisiana. To facilitate our use of these isolates as biological control agents against the RWW, a study was conducted in which the isolates were genetically fingerprinted to assess their diversity. The results of this study indicate that most of the B. bassiana isolates belong to one or the other of two groups. However, some isolates were found to have unique genetic fingerprints. This study suggests that in the vicinity of the Rice Research Station some types of B. .bassiana isolates commonly infect the RWW while others do not.
Technical Abstract: Random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) was used to examine genetic diversity among Beauveria bassiana isolates from infected rice water weevil (RWW), Lissorhoptrus oryzophilus, collected at the Rice Research Station (Crowley, LA). Most of the B. bassiana isolates tightly clustered into one or the other of two groups with members in each group exhibiting greater than eighty-seven percent similarity. Since grou 2 isolates exhibited more similarity with two exogenous culture collection isolates than with group 1, the two groups appear to represent distinct populations. Three B. bassiana soil isolates also clustered within the two groups while one soil isolate did not tightly cluster with any of the RWW isolates. The results suggest that in the vicinity of the Rice Research Station certain genotypes of B. bassiana commonly infect the RWW while others do not.