AUTHOR=Wanchoo Arun , Zhang Wei , Ortiz-Urquiza Almudena , Boswell John , Xia Yuxian , Keyhani Nemat O. 

TITLE=Red Imported Fire Ant (Solenopsis invicta) Chemosensory Proteins Are Expressed in Tissue, Developmental, and Caste-Specific Patterns

JOURNAL=Frontiers in Physiology

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2020.585883

DOI=10.3389/fphys.2020.585883

ISSN=1664-042X

ABSTRACT=<p>The red imported fire ant, <italic>Solenopsis invicta</italic>, is a eusocial invasive insect that has spread worldwide. Chemosensory proteins (CSPs) are ligand-binding proteins that participate in a diverse range of physiological processes that include olfaction and chemical transport. Here, we performed a systematic survey of the expression of the 21 gene <italic>S. invicta CSP</italic> family that includes at least two groups of apparent <italic>S. invicta</italic>-specific gene expansions. These data revealed caste, tissue, and developmental stage-specific differential expression of the <italic>SiCSPs</italic>. In general, moderate to high <italic>SiCSP</italic> expression was seen in worker antennae and abdomen tissues with lower expression in head/thorax regions. Male and female alates showed high antennal expression of fewer <italic>SiCSPs</italic>, with the female alate thorax showing comparatively high <italic>SiCSP</italic> expression. <italic>SiCSP</italic> expression was lower in male alates tissues compared to workers and female alates, albeit with some highly expressed <italic>SiCSPs</italic>. <italic>SiCSP</italic> expression was low during development including in eggs, larvae (early and late instars), and pupae. Global analyses revealed examples of conserved, divergent, and convergent <italic>SiCSP</italic> expression patterns linked to phylogenetic relationships. The developmental and caste-specific variation seen in <italic>SiCSP</italic> expression patterns suggests specific functional diversification of CSPs that may translate into differential chemical recognition and communication among individuals and/or reflect other cellular roles of CSPs. Our results support a model for CSPs acting as general ligand carriers involved in a wide range of physiological processes beyond olfaction. As compared to the expression patterns of the <italic>S. invicta</italic> odorant binding proteins (OBPs), an inverse correlation between <italic>SiOBP</italic> and <italic>SiCSP</italic> expression was seen, suggesting potential complementary and/or compensatory functions between these two classes of ligand carriers.</p>