Submitted to: Annals of the Entomological Society of America
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 7, 2000
Publication Date: N/A
Interpretive Summary: The Hessian fly is one of the most destructive insect pests of wheat in the world. For more than forty year resistant wheat has been the primary method of control in the United States. This resistance causes Hessian fly larvae to die soon after they infest the plant. As a result of the widespread use of resistant wheat, Hessian fly populations (biotypes) have evolved that can live on formally resistant wheat. To help wheat breeders continue the effective control of Hessian fly we are identifying genes in the insect that enable it to overcome resistance in wheat. We are doing this by determining where genes in the insect are located. To aid in this, we have isolated a gene from the insect and studied how it works. The gene is a member of a group of genes in the insect and can be used to determine where genes in the insect that overcome resistance in wheat are located. This will help scientists isolate these genes and find out why some biotypes of the insect are unaffected by the resistance in wheat. This knowledge as well as knowledge about how genes in the insect work will make certain scientists and breeders can continue durable protection of the wheat crop.
Technical Abstract: A clone of the Drosophila melanogaster gene Act5C was used to isolate an actin gene from a Hessian fly genomic library in phage lambda. A combined molecular and cytological analysis with the Hessian fly, Mayetiola destructor (Say), actin gene (designated act1) was undertaken. The coding region of this gene was contiguous and encoded a protein that was 98.9% identical to the intersegmental muscle actin 87E from D. melanogaster and >97% identitical to the three other muscle actins from D. melanogaster as well as the muscle actins from Bombyx mori. In contrast with the muscle actins, the actin 1 from Hessian fly shared less amino acid identity (94-95%) with the cytoplasmic actins from D. melanogaster and Anopheles gambiae with differences occurring in a conserved region of the cytoplasmic actins proposed to function in interaction with actin binding proteins. These results are consistent with the Hessian fly act1 gene encoding a muscle actin. When compared with the Drosophila Act87E gene, the Hessian fly act1 gene revealed 81% identity at the nucleotide level, with most of the variation associated with third-codon-position G+C content. Codon usage bias in the act1 gene was also determined. Southern gel blot analyses as well as in situ hybridization on salivary polytene chromosomes using act1 as the probe revealed a gene family with at least five members encodes the actins in Hessian fly. Future identification of promoters for actins from Hessian fly should prove of use for gene expression in transgenic constructs.