Volume 32, Issue 6 p. 603-614
Original Article

Identification and characterisation of PRXamide peptides in the western flower thrips, Frankliniella occidentalis

Seung-Hwan Yun

Seung-Hwan Yun

Gyeonggi-do Agricultural Research and Extension Services, Hwaseong-si, Republic of Korea

Contribution: Funding acquisition, Writing - original draft, ​Investigation, Data curation, Methodology, Validation, Resources

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Hyo Sang Jang

Hyo Sang Jang

Horticultural Crops Research Unit, USDA-ARS, Corvallis, Oregon, USA

Department of Horticulture, Oregon State University, Corvallis, Oregon, USA

Contribution: Writing - original draft, Methodology, ​Investigation, Data curation

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Seung-Joon Ahn

Seung-Joon Ahn

Department of Biochemistry, Molecular Biology, Entomology, and Plant Pathology, Mississippi State University, Mississippi State, Mississippi, USA

Contribution: ​Investigation, Writing - original draft, Conceptualization, Methodology, Writing - review & editing, Data curation

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Briana E. Price

Briana E. Price

Horticultural Crops Research Unit, USDA-ARS, Corvallis, Oregon, USA

Contribution: ​Investigation, Writing - original draft, Methodology, Data curation

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Daniel K. Hasegawa

Daniel K. Hasegawa

Crop Improvement and Protection Research Unit, USDA-ARS, Salinas, California, USA

Contribution: Writing - original draft, Writing - review & editing, Funding acquisition

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Man-Yeon Choi

Corresponding Author

Man-Yeon Choi

Horticultural Crops Research Unit, USDA-ARS, Corvallis, Oregon, USA

Correspondence

Man-Yeon Choi, Horticultural Crops Research Unit, USDA-ARS, 3420 NW Orchard Ave, Corvallis, OR 97330, USA.

Email: [email protected]

Contribution: Conceptualization, ​Investigation, Funding acquisition, Writing - original draft, Writing - review & editing, Methodology, Supervision, Project administration

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First published: 02 June 2023
Citations: 1

Abstract

Insect CAPA-PVK (periviscerokinin) and pyrokinin (PK) neuropeptides belong to the PRX family peptides and are produced from capa and pyrokinin genes. We identified and characterised the two genes from the western flower thrips, Frankliniella occidentalis. The capa gene transcribes three splice variants, capa-a, -b, and -c, encoding two CAPA-PVKs (EVQGLFPFPRVamide; QGLIPFPRVamide) and two PKs (ASWMPSSSPRLamide; DSASFTPRLamide). The pyrokinin mRNA encodes three PKs: DLVTQVLQPGQTGMWFGPRLamide, SEGNLVNFTPRLamide, and ESGEQPEDLEGSMGGAATSRQLRTDSEPTWGFSPRLamide, the most extended pheromone biosynthesis activating neuropeptide (PBAN) ortholog in insects. Multiple potential endoproteolytic cleavage sites were presented in the prepropeptides from the pyrokinin gene, creating ambiguity to predict mature peptides. To solve this difficulty, we used three G protein-coupled receptors (GPCRs) for CAPA-PVK, tryptophan PK (trpPK), and PK peptides, and evaluated the binding affinities of the peptides. The binding activities revealed each subfamily of peptides exclusively bind to their corresponding receptors, and were significant for determining the CAPA-PVK and PK peptides. Our biological method using specific GPCRs would be a valuable tool for determining mature peptides, particularly with multiple and ambiguous cleavage sites in those prepropeptides. Both capa and pyrokinin mRNAs were strongly expressed in the head/thorax, but minimally expressed in the abdomen. The two genes also were clearly expressed during most of the life stages. Whole-mounting immunocytochemistry revealed that neurons contained PRXamide peptides throughout the whole-body: four to six neurosecretory cells in the head, and three and seven pairs of immunostained cells in the thorax and abdomen, respectively. Notably, the unusual PRXamide profiles of Thysanoptera are different from the other insect groups.

CONFLICT OF INTEREST STATEMENT

The authors declare that there is no conflict of interest.

DATA AVAILABILITY STATEMENT

Data sharing not applicable to this article as no datasets were generated or analysed during the current study.