Laboratory evaluation of the virulence of Beauveria bassiana isolates to the sorghum shoot borer Chilo partellus Swinhoe (Lepidoptera: Pyralidae) and their characterization by RAPD-PCR

Devi, K U and Padmavathi, J and Sharma, H C and Seetharama, N (2001) Laboratory evaluation of the virulence of Beauveria bassiana isolates to the sorghum shoot borer Chilo partellus Swinhoe (Lepidoptera: Pyralidae) and their characterization by RAPD-PCR. World Journal of Microbiology and Biotechnology, 17 (2). pp. 131-137. ISSN 1573-0972

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Abstract

Beauveria bassiana has long been used as a mycopesticide. It has a wide host range; isolates have been reported to differ in host range and virulence to a given insect species. Identification of a molecular marker linked to a virulent phenotype to a target pest would be useful in screening for isolates effective against it. Twenty B. bassiana isolates were tested for their virulence to the second instar larvae of C. partellus in laboratory bioassays and their DNA fingerprints were generated by random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR). Three arbitrary categories of aggressiveness were chosen; isolates that caused >70%, between 70 and 40% and <40% larval mortality were grouped as highly, medium and less aggressive types, respectively. In the RAPD analysis, a 30% variability was observed among the isolates; which clustered into three major groups. The groups, based on virulence rating, did not match with the RAPD clusters. One of the highly aggressive isolates clustered with less aggressive isolates in one cluster and the other grouped along with the medium aggressive isolates in a different cluster. The B. bassiana isolates were classified phenotypically based on the taxonomic order of the original insect host and the climatic zone (tropical/temperate) from which they were isolated. No correlation between the aggressiveness of the isolate and the relatedness of the original insect host to the tested insect was observed; both the highly aggressive isolates were from coleopteran insects. A correlation was found between the RAPD grouping and the phenotypic classification of the isolates. All the lepidopteran isolates grouped into one major cluster, most sub-clusters were constituted by isolates from the same climatic zone.

Item Type:	Article
Divisions:	UNSPECIFIED
CRP:	UNSPECIFIED
Uncontrolled Keywords:	Beauveria bassiana - Chilo partellus - entomopathogenic fungus - laboratory bioassays - sorghum shoot borer - RAPD fingerprints - virulence
Subjects:	Mandate crops > Sorghum
Depositing User:	Library ICRISAT
Date Deposited:	26 Sep 2011 09:24
Last Modified:	26 Sep 2011 09:24
URI:	http://oar.icrisat.org/id/eprint/1838
Official URL:	http://dx.doi.org/10.1023/A:1016633427739
Projects:	UNSPECIFIED
Funders:	UNSPECIFIED
Acknowledgement:	UNSPECIFIED
Links:	Author

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