Filling in the gaps: A reevaluation of the Lygus hesperus peptidome using an expanded de novo assembled transcriptome and molecular cloning

Authors: Hull, Joe; Gross, Roni; Brent, Colin; CHRISTIE, ANDREW - University Of Hawaii

Submitted to: General and Comparative Endocrinology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/29/2020
Publication Date: 3/1/2021
Citation: Hull, J.J., Gross, R.J., Brent, C.S., Christie, A.E. 2021. Filling in the gaps: A reevaluation of the Lygus hesperus peptidome using an expanded de novo assembled transcriptome and molecular cloning. General and Comparative Endocrinology. 303. Article 113708. https://doi.org/10.1016/j.ygcen.2020.113708.
DOI: https://doi.org/10.1016/j.ygcen.2020.113708

Interpretive Summary: Neuropeptides control and regulate virtually every aspect of insect biology from growth and development to critical behaviors such as mating and feeding. Consequently, targeted disruption of these neuropeptide systems has great potential as a pest management strategy. Despite recent advances, our knowledge of these systems in the western tarnished plant bug, an important pest of numerous crops in the western United States, remain limited. To expand current resources, we used previously generated transcriptomic datasets for heads and male reproductive tissues to search for additional peptides. The peptides predicted here, in combination with those identified previously, expand the L. hesperus peptide database to 240 peptides encompassing 31 families. These data provide base-line information for better understanding the physiology underlying the western tarnished plant bug and can be used to facilitate the development of improved biologically-based management strategies.

Technical Abstract: Peptides are the largest and most diverse class of molecules modulating physiology and behavior. Previously, we predicted a peptidome for the western tarnished plant bug, Lygus hesperus, using transcriptomic data produced from whole individuals. A potential limitation of that analysis was the masking of underrepresented genes, in particular tissue-specific transcripts. Here, we reassessed the L. hesperus peptidome using a more comprehensive peptidome comprised of the previous transcriptomic data as well as tissue-specific reads produced from heads and accessory glands. This augmented assembly significantly improves coverage depth with transcripts for essentially all of the previously identified families reidentified in addition to transcripts encoding new peptide precursors, including: adipokinetic hormone-corazonin-like peptide, diuretic hormone 44, FMRFamide-like peptide, leucokinin, and RYamide. Transcripts encoding precursors for several families not targeted in our initial study were also identified in the expanded assembly, i.e., agatoxin-like peptide, CNMamide, neuropeptide-like precursor 1, and periviscerokinin. To provide increased confidence for the in silico data, the open reading frames of a subset of the newly identified transcripts were amplified using RT-PCR and sequence validated. Further PCR-based profiling of the putative L. hesperus agatoxin-like peptide transcript revealed evidence of alternative splicing with near ubiquitous expression across L. hesperus development, suggesting a functional role beyond that typically associated with agatoxin-like peptides. The peptides predicted here, in combination with those identified in our earlier study, expand the L. hesperus peptidome to 240 peptides encompassing 31 families, providing an improved platform for initiating molecular and physiological investigations into peptidergic functionality in this non-model agricultural pest.