Submitted to: Genbank
Publication Type: Other
Publication Acceptance Date: 8/12/2003
Publication Date: 9/1/2003
Citation: Yocum, G.D. 2003. Downregulation of the purine synthesis enzyme purh during adult diapause in the Colorado potato beetle, Leptinotarsa decemlineata. GenBank. Accession number AY357301.
Interpretive Summary: Environmental conditions required for reproduction and development are normally restricted to only a small part of the year, especially in the temperate zones where organisms must survive winter with its associated low temperatures, low humidity and lack of food. The ability to enter into a state of dormancy is normally restricted to one developmental stage of an organism's life cycle and is characterized by suppressed metabolism and increased tolerance of environmental stresses. Dormancy presents both challenges and opportunities in managing organisms within an agricultural setting. The ability to survive the environmental stress associated with a given geographic region enables noxious species such as insect pests and disease causing agents to become established. On the other hand, an organism's state of dormancy is often exploited to our benefit. Dormancy allows storage and shipment of grains, legumes, nuts, etc., as well as long-term storage in seed banks to preserve genetic diversity. The cost of using beneficial insects used in IPM programs is reduced when quantities of the insects can be accumulated and stored in diapause. A key aspect of an organism's survival in dormancy is the regulation of its metabolic reserves. This publication describes the characterization of a cDNA clone of purH isolated from Colorado potato beetle. PurH is a critical enzyme of purine synthesis. Purines play a central role in energy flow within an organism and in the hormonal regulation of development. This cDNA clone will be used to study purine regulation during dormancy in the Colorado potato beetle, the major pest of potato in the northern hemisphere.
Technical Abstract: A cDNA clone for Leptinotarsa decemlineata purine synthesis enzyme 5-aminoimidazole-4-carboxamide ribonucleotide formyltransferase/IMP cyclohydrolase (purH) was isolated from diapausing adults. The clone encodes for a deduced protein 594 amino acids in length with 73% identity, 83% similarity to purH from Drosophila melanogaster. Developmental studies revealed that LdpurH is expressed at nearly constant high levels in both nondiapausing and prediapause adults. LdpurH expression during the first 20 days of diapause is equivalent to that seen in nondiapausing beetles, after which expression decreases.