Antennal transcriptome analysis of the Red Palm Weevil, Rhynchophorus ferrugineus, to characterize the pheromone receptors

Antennal transcriptome analysis of the Red Palm Weevil, Rhynchophorus ferrugineus to characterize the pheromone receptors

B. Antony¹*, A. Soffan^1,2,  J. Jakše³, S. A. Aldosari¹, S.  Alfaifi¹, M. Abdelazim¹, A. S. Aldawood² and A. Pain⁴

¹King Saud University, Chair of Date Palm Research, College of Food and Agriculture Sciences, Riyadh, Saudi Arabia 11451

² King Saud University, EERU, Department of Plant Protection, Riyadh, Saudi Arabia 11451

³University of Ljubljan, Centre for Plant Biotechnology and Breeding, 1000 Ljubljana, Slovenia

⁴KAUST, Computational Bioscience Research Center, Jeddah, Thuwal 23955-6900, Saudi Arabia

*bantony@ksu.edu.sa

The date palm is an extremely important fruit crop in Middle East countries and the Red Palm Weevil (RPW) Rhynchophorus ferrugineus (Olivier) is considered as one of the most damaging invasive insect species, causes major economic losses in palm trees. RPW has been the major date palm pest in Saudi Arabia causing heavy losses every year. The main eco-friendly method of controlling this pest is to use of aggregation pheromone in the pheromone trap; composed of ferrugineol (4-methyl-5-nonanol) and 4-methyl-5-nonanone. The mechanism of pheromone reception involve the pheromone molecule would binds to odorant receptors (OR) proteins and signals are transmitted to the central nervous system where it is processed and identified by the brain and messages are then passed to the effector neurons and finally the behavioral response elicited. Here we report the next-generation sequencing of antennal transcriptome and transcripts of highly expressed chemosensory multi-gene families from the RPW.

To make easy identifying OR proteins, we developed a normalized cDNA library of RPW antennae and the sequencing yielded a total of 194,157,678 raw reads, which assembled into 35,667 contigs/unigene with an average length of 857bp. Using BLAST2GO searches we identified a large number of highly expressed transcripts of major chemosensory multi-gene families, viz., odorant binding proteins, chemosensory proteins, odorant receptors, sensory neuron membrane proteins, and gustatory and ionotropic receptors. Comparison of RPW ORs with four other Coleopteran antennal transcriptome data revealed majority of ORs placed among 7 subfamilies of ORs described earlier. Predicted protein sequences were compared with flour beetle, cerambycid beetle and bark beetle and Drosophila and identified coleopteran-specific, highly conserved ORs and also predicted the unique ORs putatively involved in aggregation pheromone detection in RPW. Further characterization of ORs involved in RPW aggregation pheromone detection and protein expression in in vitroexpression system are in progress.

 

Acknowledgments: Grant-aid from NPST-KACST 12-AGR2854-02.