PLoS ONE (2012) 7 (3 - e34027)

Yosep S. Mau, Patrick J. Collins, Gregory J. Daglish, Manoj K. Nayak and Paul R. Ebert (2012)
The rph2 gene is responsible for high level resistance to phosphine in independent field strains of Rhyzopertha dominica
PLoS ONE 7 (3 - e34027)
Abstract: The lesser grain borer Rhyzopertha dominica (F.) is one of the most destructive insect pests of stored grain. This pest has been controlled successfully by fumigation with phosphine for the last several decades, though strong resistance to phosphine in many countries has raised concern about the long term usefulness of this control method. Previous genetic analysis of strongly resistant (SR) R. dominica from three widely geographically dispersed regions of Australia, Queensland (SR_QLD), New South Wales (SR_NSW) and South Australia (SR_SA), revealed a resistance allele in the rph1 gene in all three strains. The present study confirms that the rph1 gene contributes to resistance in a fourth strongly resistant strain, SR2_QLD, also from Queensland. The previously described rph2 gene, which interacts synergistically with rph1 gene, confers strong resistance on SR_QLD and SR_NSW. We now provide strong circumstantial evidence that weak alleles of rph2, together with rph1, contribute to the strong resistance phenotypes of SR_SA and SR2_QLD. To test the notion that rph1 and rph2 are solely responsible for the strong resistance phenotype of all resistant R. dominica, we created a strain derived by hybridising the four strongly resistant lines. Following repeated selection for survival at extreme rates of phosphine exposure, we found only slightly enhanced resistance. This suggests that a single sequence of genetic changes was responsible for the development of resistance in these insects.
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Database assignments for author(s): Patrick J. Collins, Manoj K. Nayak

Research topic(s) for pests/diseases/weeds:
pesticide resistance of pest

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Rhyzopertha dominica	Stored grain	Australia (South+SE)
	Rhyzopertha dominica	Stored grain	Australia (NT+QLD)