Unveiling genetic defense mechanisms: expression analysis of hym, AmNrx1, and CYP9Q3 genes in Varroa-resistant anatolian honey bees

Abstract

The Varroa destructor represents a significant threat to honey bees, leading to substantial yield losses and declines in colony health. Defense behaviors, including grooming (auto and allogrooming), serve as crucial mechanisms against Varroa infestations, yet the genetic basis of these behaviors remains elusive. This study examines the expression levels of hymenoptaecin (hym), neurexin-1 (AmNrx1), and CYP9Q3, potentially associated with defense behavior, in colonies of the Mu & gbreve;la honey bee ecotype (Apis mellifera anatoliaca) subjected to a Varroa selection program. Worker bees from 23 control groups and 23 colonies under selection were evaluated by using qPCR analysis. Results reveal a significant upregulation of hym, AmNrx1, and CYP9Q3 genes in the selected group, with fold changes of 2.9, 2.95, and 3.26 respectively compared to controls (p < 0.01). This suggests that selection against Varroa induces alterations in gene expression linked to Varroa exposure behaviors. These findings advocate for the potential use of hym, AmNrx1, and CYP9Q3 genes in preselection for future Varroa-resistant programs in honey bees. Supported by previous studies, these genes may facilitate the establishment of populations with enhanced defense behaviors, such as autogrooming and allogrooming.