Comprehensive Annotation of Olfactory and Gustatory Receptor Genes and Transposable Elements Revealed Their...

Area of Science:

• Genomics
• Evolutionary Biology
• Insect Molecular Biology

Background:

• Gene duplication and transposable elements (TEs) are key drivers of genomic innovation and adaptation.
• While studied in plant pathogens, their role in insect pests, particularly aphids, is less understood.
• Olfactory receptors (ORs) and gustatory receptors (GRs) are crucial for aphid host recognition.

Purpose of the Study:

• To investigate the role of gene duplication and TEs in the evolution of OR and GR genes in aphids.
• To correlate genomic features with aphid host range breadth.
• To provide insights into the adaptive evolution of sensory receptors in insect pests.

Main Methods:

• Analysis of 521 OR and 399 GR genes across 12 aphid genomes.
• Identification and analysis of transposable elements (TEs) in proximity to OR and GR genes.
• Application of deep learning models to predict functional protein regions and evolutionary signatures.

Main Results:

• Aphids with broader host ranges showed higher evolutionary rates in gene families related to host interaction.
• OR and GR genes evolved via duplications and were shaped by diversifying selection, indicating adaptation to new hosts.
• Younger TEs were enriched near OR genes, suggesting a role in their diversification, but TE-associated ORs had reduced functional potential.
• TE-associated GRs retained signatures of adaptation, unlike ORs.

Conclusions:

• TE activity may promote functional innovation in GRs while potentially constraining ORs in aphids.
• Gene duplication, selection, and TE dynamics collectively shape the evolution of sensory genes in insect pests.
• This study offers mechanistic insights into adaptive evolution and provides a chromosome-scale assembly for Dysaphis plantaginea.