A FLOWERING LOCUS T ortholog is associated with photoperiod‐insensitive flowering in hemp ( Cannabis sativa L.)

Cannabis sativa L., one of humanity’s oldest cultivated crops, has a complex domestication history due to its diverse uses for fibre, seed, oil and drugs, and its wide geographic distribution. This review explores how human selection has shaped the biology of hemp and drug-type Cannabis, focusing on acquisition and utilisation of nitrogen and phosphorus, and how resulting changes in source-sink relations shape their contrasting phenology. Hemp has been optimized for rapid, slender growth and nutrient efficiency, whereas drug-type cultivars have been selected for compact growth with large phytocannabinoid producing female inflorescences. Understanding these nutrient use and ontogenetic differences will enhance our general understanding of resource allocation in plants. Knowledge gained in comparison with other model species, such as tomato, rice or Arabidopsis thaliana can help inform crop improvement and sustainability in the Cannabis industry.

Same, yet different: towards understanding nutrient use in hemp- and drug-type Cannabis

Wee Y,

Berkowitz,

Whelan

et al. 2024

From fibers to flowering to metabolites: unlocking hemp (Cannabis sativa) potential with the guidance of novel discoveries and tools

Pancaldi,

Salentijn,

Trindade

2024

Cannabis sativa L. is an ancient crop whose agricultural adoption has been interrupted to prevent the use of marijuana as psychoactive drug. Nevertheless, hemp – the Cannabis sativa type with low concentrations of intoxicating Δ9-tetrahydrocannabinoid – is experiencing resurged interest thanks to loosened cultivation restrictions and its potential as multipurpose bio-based crop. In fact, hemp has valuable applications, including production of medicines from its non-intoxicating cannabinoids, food, medical, and industrial uses of its seed oil rich in poly-unsaturated fatty acids, and production of fibers for textiles and industry from its stems. Recently, several hemp genomic and genetic resources have been developed, allowing for a significant expansion of the genetic knowledge on major hemp traits, as cannabinoids, oil, and fibers synthesis, and regulation of flowering and sex determination. Still, hemp is an under-improved crop, whose advancement will depend on the ability to expand and collectively use the novel resources available in light of the fast advancements in bioinformatics and plant phenotyping technologies. This review discusses on the current genetic and genomic knowledge on the most important hemp traits, and provides a perspective on how to further expand such knowledge and tackle hemp improvement with the most up-to-date tools for plant and hemp research.

Identification of genes associated with sex expression and sex determination in hemp (Cannabis sativa L.)

Shi,

Toscani,

Dowling

et al. 2024

Dioecy in flowering plants has evolved independently many different times, and thus the genetic mechanisms underlying sex determination are diverse. In hemp (Cannabis sativa), sex is controlled by a pair of sex chromosomes (XX for females and XY for males). In an attempt to understand the molecular mechanism responsible for sex expression in hemp plants, we carried out RNA-Seq of male and female plants at different developmental stages. Using a pipeline involving differential gene expression analysis and weighted gene co-expression network analysis, we identified genes important for male and female flower development. We also demonstrate that sex-biased expression is already established at very early vegetative stages, before the onset of reproductive development, and several genes encoding transcription factors of the REM, bZIP and MADS family as candidate sex determination genes in hemp. Our findings demonstrate that the gene regulatory networks governing male and female development in hemp diverge already at a very early stage, leading to profound morphological differences in male and female hemp plants.