Novel RNA Viruses from the Transcriptome of Pheromone Glands in the Pink Bollworm Moth, Pectinophora gossypiella

In this study, we analyzed the transcriptome obtained from the pheromone gland isolated from two Israeli populations of the pink bollworm Pectinophora gossypiella to identify viral sequences. The lab population and the field samples carried the same viral sequences. We discovered four novel viruses: two positive-sense single-stranded RNA viruses, Pectinophora gossypiella virus 1 (PecgV1, a virus of Iflaviridae) and Pectinophora gossypiella virus 4 (PecgV4, unclassified), and two negative-sense single-stranded RNA viruses, Pectinophora gossypiella virus 2 (PecgV2, a virus of Phasmaviridae) and Pectinophora gossypiella virus 3 (PecgV3, a virus of Phenuiviridae). In addition, sequences derived from two negative-sense single-stranded RNA viruses that belong to Mononegavirales were found in the data. Analysis of previous transcriptome sequencing data derived from the midgut of pink bollworm larvae of a USA population only identified PecgV1, but no other viruses. High viral sequence coverages of PecgV1 and PecgV4 were observed in both field and lab populations. This is the first report of viral sequences discovered from the pink bollworm. Results from this investigation suggest that the pink bollworm harbors multiple viruses. Further investigation of the viral pathogens may help to develop novel pest management strategies for control of the pink bollworm.

Evolution of resistance to mating disruption in the pink bollworm moth evidence and possible mechanism

t The pink bollworm, Pectinophoragossypiellais a key pest of cotton world-wide. In Israel mating disruption sex pheromone is used in all cotton fields and recent repeated outbreaks of the pest populations has suggested a change in the population sex pheromone characteristics. The research goals were to (1) determine the change in pheromone characteristic of PBW females after long experience to Mating Disruption (MD), (2) to test the male’s antennae response (EAG) to pheromone characteristics of laboratory, naive females, and of field collected, MD experienced females, (3) to analyse the biosynthetic pathway for possible enzyme variations, (4) to determine the male behavioural response to the pheromone blend involved in the resistance to MD. The experiments revealed that (1) MD experienced females produced pheromone blend with higher ZZ ratio than lab reared (MD naive females) that typically produced ZZ:EE ratio of 1:1. (2) Male’s origin did not affect its response to pheromone characteristics of lab or field females. (3) A transcriptome study demonstrated many gene-encode enzymes in the biosynthetic pathway, but some of the transcripts were produced in differing levels in the MD resistant populations. (4) Male origin (field or lab) influenced males’ choice of mate with strong preference to females sharing the same origin. However, when MD was applied, males of both populations were more attracted to females originated form failed MD treated fields. We conclude that in MD failed fields a change in the population mean of the ratio of the pheromone components had occurred. Males in these fields had changed their search “image” accordingly while keeping the wide range of response to all pheromone characteristics. The change in the pheromone blend is due to different level of pheromone related enzyme production.