BIOLOGY, GENOMICS, AND INTEGRATED PEST MANAGEMENT OF INVASIVE ANTS
Location: Imported Fire Ant and Household Insects
Title: PBAN gene architecture and expression in the fire ant, Solenopsis invicta
Submitted to: Journal of Insect Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 24, 2010
Publication Date: January 1, 2011
Citation: Choi, M.Y., Vander Meer, R.K., Shoemaker, D.D., Valles, S.M. 2011. PBAN gene architecture and expression in the fire ant, Solenopsis invicta. Journal of Insect Physiology. 57(1):161-165.
Interpretive Summary: The red imported fire ant, S. invicta, is among the world’s 100 worst invasive alien species. In the United States this ant species infests more than 320 million acres in 13 southern tier states and Puerto Rico and are spreading northward. The affected economic sectors are broad ranging and include households, electric service and communications, agriculture, schools and recreation areas. It is estimated to be responsible for almost $7 billion annually in damage repair, medical care, and control costs. Currently, S. invicta has changed from an invasive pest ant in the United States to a global problem, with infestations occurring in Australia, Taiwan, mainland China, Mexico and many Caribbean Island countries. Therefore, novel biologically-based or environment friendly methods of controlling these pest ants are needed to reduce our dependence on pesticides. Insect neurohormones as intercellular messenger play many critical roles during insect development and as adults. Major part of insect hormones is consisted of neuropeptides. Identification and characterization of insect neuropeptides in the fire ant will lead to develop new control methods. Scientists at the Center for Medical, Agricultural and Veterinary Entomology, USDA, ARS, Gainesville, FL have established for the first time the identification and characterization of the fire ant PBAN (Pheromone Biosynthesis Activating Neuropeptide: PBAN) gene, and characterized the localization of this peptide produced. The scientists continued to identify the fire ant PBAN genome and characterize the gene expression pattern from different tissue parts using different PCR techniques. We discovered that more than one gene is present in the abdominal tissue. Little is known about the regulation of pheromone production and release, nor whether protein hormones, especially neuropeptides, are involved in key physiological and endocrinal processes during development. This is the initial step in developing novel, non-insecticide methods for fire ant control based on the interference of normal neuropeptide hormone functions.
The PBAN/Pyrokinin peptides are a major neuropeptide family characterized by a common FXPRLamide at the C-termini. These peptides are distributed ubiquitously in the Insecta and are involved in many essential endocrine functions, e.g. pheromone production. We report the gene architecture of the fire ant Solenopsis invicta PBAN (Soi-PBAN) gene, including the exon and intron boundaries. Furthermore, we quantified expression of the Soi-PBAN mRNA in the head, thorax and abdomen of the fire ant. The Soi-PBAN gene is comprised of three exons and two introns (13,358 nucleotides), which is nearly 2x or 4x as large as the lepidopteran PBAN gene. The Soi-PBAN mRNA expression level was highest in the head, followed by the thorax, and abdomen of adult ants. Expression in the abdominal tissues was expected to be similar to the head, or at least higher than thorax because strong PBAN immunoreactive neurons were detected previously in brain-subesophageal and abdominal ganglia. This unexpected result suggests that another FXPRL gene, e.g. a capa gene, could be dominant in the abdomen rather than Soi-PBAN gene.