Loss of daylength sensitivity by splice site mutation in Cannabis

Abstract

Adaptations to high latitude photoperiods have been under positive selection during the domestication of many short-day (SD) flowering crops. Photoperiod insensitivity (auto-flowering) in drug-type Cannabis sativa circumvents the need for SD flowering requirements making outdoor cultivation in high latitudes possible. However, the benefits of photoperiod insensitivity are counterbalanced by low cannabinoid contents and poor flower quality in auto-flowering genotypes. Despite recent legalization in some countries, a mechanistic understanding of photoperiod insensitivity in cannabis is still lacking. Herein, we identify a splice site mutation within PSEUDO-RESPONSE REGULATOR 37 (CsPRR37) in auto-flowering cannabis that causes photoperiod insensitivity. Using a combination of GWAS, fine mapping, and gene expression analyses, our results strongly indicate CsPRR37 as the most likely candidate for causing photoperiod insensitivity. Research into the pervasiveness of this mutation and others effecting flowering time will help elucidate its domestication history and advance cannabis breeding towards a more sustainable outdoor cultivation system.

Domesticated cannabinoid synthases amid a wild mosaic cannabis pangenome

“…Indeed, the 17 instances of this inversion were found to be heterozygous in 15 samples and homozygous in one. This inverted region contains 1,203 genes, spanning many functions, including the core circadian and flowering time gene PSEUDO RESPONSE REGULATOR 3 ( PRR3 ) implicated in the DN behavior of “autoflower” cannabis 21,26,58 , but are significantly enriched for catalytic activity, transport activity, and binding gene ontology (GO) categories. Pairwise SNP r 2 values and local PCA plots of this area suggest some level of haplotype formation and elevated linkage disequilibrium (LD) across this region, especially at the interior breakpoint (Supplemental Fig.…”

AFLOWERING LOCUS Tortholog is associated with photoperiod-insensitive flowering in hemp (Cannabis sativaL.)

“…Two recent mapping studies have suggested C. sativa homologs of APETALA2 and PSEUDO-RESPONSE REGULATOR 37 (PRR37) as candidate genes within Autoflower1 (Garfinkel et al, 2023;Leckie et 2023). Alterations of PRR37 homologs in T. aestivum, O. sativa and Sorghum bicolor are known to confer photoperiod insensitivity due to de-repressed FT expression (Beales et al, 2007;Koo et al, 2013;Murphy et al, 2011).…”

Characterizing the expression patterns of short-day flowering genes, the manipulation of their expression using red-far red wavelengths, and the resulting phenotype/ chemotype inCannabis sativa

“…in cannabis, and it has been shown that a mutation of that gene is correlated with the autoflowering trait, or lack of response to photoperiod 12 . GHD7 has also been implicated as a predictor of yield in rice 10 .…”

“…Cannabis CONSTANS-like genes have been identified, and in fact there are at least 13 expressed CONSTANS-like genes 15 . In cannabis, florigen-like, PRR37-like, and SOC1-like genes have also been identified 12,16 . In this paper, we present experimental data which characterizes the expression patterns of these genes, their responsiveness to phytochrome via manipulation of the ratio of red to far red light, and the resulting impact on phenotype and chemotype.…”

“…These enhancer proteins-GHD7, PRR37 and DTH8-are CDL gated and differentially expressed based on photoperiod 9–11 . A homolog of PRR37 has been identified in cannabis, and it has been shown that a mutation of that gene is correlated with the autoflowering trait, or lack of response to photoperiod 12 . GHD7 has also been implicated as a predictor of yield in rice 10 .…”