Gene expression explains host choice in crop moths.

Researchers have identified and compared, on a genome-wide scale, genes linked to chemoreception in two of the world's major solanaceous pests. The work mapped protein families involved in odor detection in the Colorado potato tuber moth (Phthorimaea operculella) and in the tomato leafminer (Phthorimaea absolutaThe results indicate molecular targets with potential for behavior-based management strategies.

In the genome of Phthorimaea operculellaThe authors identified 47 odor-binding proteins (OBPs), 26 chemosensory proteins (CSPs), and two sensory neuron membrane proteins (SNMPs). In P. absoluta, the survey found 39 OBPs, 24 CSPs, and two SNMPs. The proteins act in the transport of volatile compounds to olfactory receptors and participate in host selection, mating, and oviposition.

Gene expression analysis, based on RNA-seq, showed strong tissue and sex specificity in Phthorimaea operculellaAntennae concentrated the majority of OBP and CSP expression. Twenty-four OBPs and four CSPs showed sexually differentiated expression in the antennae. Females exhibited higher expression of 14 OBPs and four CSPs. Males concentrated ten OBPs, one CSP, and the SNMP2 protein.

Reproductive organs

Reproductive organs also showed distinct patterns. The ovipositor concentrated three OBPs and one CSP with greater expression. The male genitalia concentrated six OBPs and five CSPs. No SNMP showed a significant difference between these tissues. The pattern suggests a role for soluble proteins in short-range chemical evaluation during oviposition and mating.

During larval development, OBP expression occurred primarily in the head, with low activity in the digestive tract. This indicates a function related to food location rather than digestion. Some OBPs also appeared in the integument, hemolymph, and fat body, suggesting additional functions beyond classical olfaction.

Evolutionary comparison

Evolutionary comparison revealed differential gene expansion between the two species. Phthorimaea operculella It presented a broader repertoire of soluble carrier proteins. The pattern suggests greater molecular diversity for recognizing volatiles from the host and the oviposition substrate.

The authors highlight that genes with high expression in the ovipositor and antennae of females emerge as candidates for functional studies. These targets may support the development of attractants, repellents, or behavioral disruption strategies. The study also points to proteins associated with pheromones in males as potential points of intervention in mating confusion programs.

Further information at doi.org/10.3390/insects17020178