Biology subjects

MacKenzie, J. O.

Publications and source records attributed to MacKenzie, J. O..

2 recordsLinked to original sources

bioRxiv2024

Mapping and characterization of a novel powdery mildew resistance locus (PM2) in Cannabis sativa L.

Breeding genetic resistance to economically important crop diseases is the most sustainable strategy for disease management and enhancing agricultural and horticultural productivity, particularly where the application of synthetic pesticides is prohibited. Powdery mildew disease, caused by the biotrophic fungal pathogen Golovinomyces ambrosiae, is one of the most prevalent threats to the cannabis and hemp industry worldwide. In this study, we used bulk-segregant analysis (BSA) combined with high-throughput sequencing to identify and map a novel single dominant resistance (R) locus (designated PM2), that strongly suppresses powdery mildew infection and sporulation in Cannabis sativa. Histochemical analysis revealed that PM2-induced resistance is mediated by a highly localized hypersensitive response mainly in the epidermal cells of the host. Importantly, genetic markers capable of tracking PM2 resistance in breeding populations were developed using associated SNPs identified in this study.

plant biology↗

bioRxiv2023

Loss of daylength sensitivity by splice site mutation in Cannabis

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.

plant biology↗