Abstract
The cannabinoid alkyl side-chain represents an important pharmacophore, where genetic targeting of alkyl homologs has the potential to provide enhanced forms of Cannabis for biopharmaceutical manufacture. Delta(9)-tetrahydrocannabinolic acid (THCA) and cannabidiolic acid (CBDA) synthase genes govern dicyclic (CBDA) and tricyclic (THCA) cannabinoid composition. However, the inheritance of alkyl side-chain length has not been resolved, and few studies have investigated the contributions and interactions between cannabinoid synthesis pathway loci. To examine the inheritance of chemical phenotype (chemotype), THCAS and CBDAS genotypes were scored and alkyl cannabinoid segregation analysed in 210 F2 progeny derived from a cross between two Cannabis chemotypes divergent for alkyl and cyclic cannabinoids. Inheritance patterns of F2 progeny were non-Gaussian and deviated from Mendelian expectations. However, discrete alkyl cannabinoid segregation patterns consistent with digenic as well as epistatic modes of inheritance were observed among F2THCAS and CBDAS genotypes. These results suggest linkage between cannabinoid pathway loci and highlight the need for further detailed characterisation of cannabinoid inheritance to facilitate metabolic engineering of chemically elite germplasm.
Highlights
Cannabis plants produce a class of therapeutically important isoprenylated resorcinyl polyketides[9], more commonly identified ascannabinoids[10]
C5 alkyl cannabinoid fractions (FC3/FC5) associated with alkyl cannabinoid loci (An loci) as well as di-/tri-cyclic cannabinoid fractions (Fdicyclic/Ftricyclic) associated with the B locus complex were determined from the fresh weight (w/w) cannabinoid content of cannabidivarinic acid (CBDVA), tetrahydrocannabivarinic acid (THCVA), cannabidiolic acid (CBDA) and delta(9)-tetrahydrocannabinolic acid (THCA)
Simple Mendelian inheritance can result in phenotypic continuity when within-genotypic class variation is large and average phenotypic differences between genotypes are negligible[45]
Summary
Cannabis plants produce a class of therapeutically important isoprenylated resorcinyl polyketides[9], more commonly identified as (phyto)cannabinoids[10]. Cannabinoids vary by isoprenyl topological arrangement[13], of which dicyclic cannabidiol (CBD)-type and tricyclic delta(9)-tetrahydrocannabinol (THC)-type cannabinoids are commonly encountered in planta[14] Another important structural feature of cannabinoids is the resorcinyl alkyl side-chain which typically occurs in either pentyl (C5) or to a lesser extent propyl (C3) configuration[15,16], a variety of odd and even carbon lengths have been reported as minor constituents in a subset of germplasm[17,18]. Resolution of associated in planta biosynthetic pathways has largely focused on C5 alkyl species[33,38]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
