A Conserved Odorant Receptor Detects the Same 1-Indanone Analogs in a Tortricid and a Noctuid Moth

Sammanfattning

Odorant receptors (ORs) interface animals with airborne chemical signals. They are under strong selection pressure and are therefore highly divergent in different taxa. Yet, some OR orthologs are highly conserved. These ORs may be tuned to odorants of broad importance, across species boundaries. Two widely distributed lepidopteran herbivores, codling moth Cydia pomonella (Tortricidae) feeding in apples and pears, and the African cotton leafworm Spodoptera littoralis, a noctuid moth feeding on foliage of a wide range of herbaceous plants, both express a receptor ortholog, OR19, which shares 58% amino acid identity and 69% amino acid similarity. Following heterologous expression in the empty neuron system of Drosophila melanogaster, we show by single sensillum recordings that CpomOR19 and SlitOR19 show similar affinity to several substituted indanes. Tests with a series of compounds structurally related to 1-indanone show that 2-methyl-1-indanone, 2-ethyl-1-indanone, 3-methyl-1-indanone and 1-indanone elicit a strong response from both ORs. A keto group in position 1 is essential for biological activity and so are both rings of the indane skeleton. However, there is an important difference in steric complementary of the indane rings and the receptor. Methyl substituents on the benzene ring largely suppressed the response. On the other hand, alkyl substituents at position 2 and 3 of the five-membered ring increased the response indicating a higher complementarity with the receptor cavity, in both CpomOR19 and SlitOR19. Our results demonstrate a conserved function of an odorant receptor in two moths that are phylogenetically and ecologically distant. It is conceivable that a conserved OR is tuned to signals that are relevant for both species, although their ecological roles are yet unknown. Our finding demonstrates that functional characterization of ORs leads to the discovery of novel semiochemicals that have not yet been found through chemical analysis of odorants from insects and their associated host plants.

Nyckelord

Cydia pomonella; Spodoptera littoralis; olfaction; olfactory receptor; 1-indanone; orthologous genes; structure activity relationships; functional characterization

Publicerad i

Frontiers in Ecology and Evolution
2015, volym: 3, artikelnummer: 131

SLU författare

• Francisco, Gonzalez

  • Institutionen för växtskyddsbiologi, Sveriges lantbruksuniversitet
    

• Sousa, Maria

• Walker, William

  • Institutionen för växtskyddsbiologi, Sveriges lantbruksuniversitet
    

• Witzgall, Peter

  • Institutionen för växtskyddsbiologi, Sveriges lantbruksuniversitet
    

• Ignell, Rickard

  • Institutionen för växtskyddsbiologi, Sveriges lantbruksuniversitet
    

• Bengtsson, Marie

  • Institutionen för växtskyddsbiologi, Sveriges lantbruksuniversitet
    

UKÄ forskningsämne

Biokemi och molekylärbiologi
Zoologi
Evolutionsbiologi

Publikationens identifierare

• DOI: https://doi.org/10.3389/fevo.2015.00131

Permanent länk till denna sida (URI)

https://res.slu.se/id/publ/69341