Integrating Discovery-driven Proteomics and Selected Reaction Monitoring To Develop a Noninvasive Assay for Geoduck Reproductive Maturation

Geoduck clams (Panopea generosa) are an increasingly
important fishery and aquaculture product along the eastern Pacific
coast from Baja California, Mexico, to Alaska. These long-lived clams
are highly fecund, although sustainable hatchery production of genetically
diverse larvae is hindered by the lack of sexual dimorphism, resulting
in asynchronous spawning of broodstock, unequal sex ratios, and low
numbers of breeders. The development of assays of gonad physiology
could indicate sex and maturation stage as well as be used to assess
the status of natural populations. Proteomic profiles were determined
for three reproductive maturation stages in both male and female clams
using data-dependent acquisition (DDA) of gonad proteins. Gonad proteomes
became increasingly divergent between males and females as maturation
progressed. The DDA data were used to develop targets analyzed with
selected reaction monitoring (SRM) in gonad tissue as well as hemolymph.
The SRM assay yielded a suite of indicator peptides that can be used
as an efficient assay to determine geoduck gonad maturation status.
Application of SRM in hemolymph samples demonstrates that this procedure
could effectively be used to assess reproductive status in marine
mollusks in a nonlethal manner.