Identification of two monoterpenes and their coding genes in Coffea arabica L. associated with the attraction of the coffee berry borer (Hypothenemus hampei)

Abstract

The coffee berry borer (CBB) is the most significant pest affecting coffee in Colombia and, globally, attracted primarily to volatiles from ripe fruits. To identify volatiles involved in host recognition, we conducted olfactometry assays using coffee fruits at different ripening stages and synthetic mixtures. A blend of limonene (25 ppm) and pinene (200 ppm) was significantly more attractive to CBB than ripe fruits or a methanol-ethanol (3:1) lure. GC‒MS confirmed both compounds in the coffee fruits, with limonene being the most abundant, especially in the ripe fruits. We identified and analyzed the terpene synthase genes responsible for limonene and pinene biosynthesis in Coffea arabica. qPCR showed these genes are exclusively expressed in fruits, with limonene synthase expression 100% higher in ripe fruits, which is correlated with peak CBB attraction. Pinene synthase also varied across ripening stages. These findings demonstrate the developmental regulation of volatile production linked to CBB behavior, revealing potential targets for pest control strategies.