Biology subjects

Toth, J. A.

Publications and source records attributed to Toth, J. A..

4 recordsLinked to original sources

bioRxiv2023

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

Hemp (Cannabis sativa L.) is an extraordinarily versatile crop, with applications ranging from medicinal compounds to seed oil and fibre products. Cannabis sativa is a short-day plant, and its flowering is tightly controlled by photoperiod. However, substantial genetic variation exists for photoperiod sensitivity in C. sativa, and photoperiod-insensitive ("autoflower") cultivars are available. Using a bi-parental mapping population and bulked segregant analysis, we identified Autoflower2, a 0.5 Mbp locus significantly associated with photoperiod-insensitive flowering in hemp. Autoflower2 contains an ortholog of the central flowering time regulator FLOWERING LOCUS T (FT) from Arabidopsis thaliana which we termed CsFT1. Extensive sequence divergence between alleles of CsFT1 was identified between photoperiod-sensitive and insensitive cultivars of C. sativa, including a duplication of CsFT1 and sequence differences especially in introns. Genotyping of several mapping populations and a diversity panel confirmed a strong correlation between CsFT1 alleles and photoperiod response as well as affirming that at least two independent loci for this agriculturally important trait, Autoflower1 and Autoflower2, exist in the C. sativa gene pool. This study reveals the multiple independent origins of photoperiod insensitivity in C. sativa, supporting the likelihood of a complex domestication history in this species. By integrating the genetic relaxation of photoperiod sensitivity into novel C. sativa cultivars, expansion to higher latitudes will be permitted, thus allowing the full potential of this versatile crop to be reached.

plant biology↗

bioRxiv2022

Plant architecture is correlated with variation in cannabinoid concentration and biomass production in Cannabis sativa

Cannabis sativa is cultivated for multiple uses including the production of cannabinoids. In developing improved production systems for high-cannabinoid cultivars, scientists and cultivators must consider the optimization of complex and interacting sets of morphological, phenological, and biochemical traits, which have historically been shaped by natural and anthropogenic selection. Determining factors that modulate cannabinoid variation within and among genotypes is fundamental to developing efficient production systems and understanding the ecological significance of cannabinoids. Thirty-two high-cannabinoid hemp cultivars were characterized for traits including flowering date and shoot-tip cannabinoid concentration. Additionally, a set of plant architecture traits, as well as wet, dry, and stripped inflorescence biomass were measured at harvest. One plant per plot was partitioned post-harvest to quantify intra-plant variation in inflorescence biomass production and cannabinoid concentration. Some cultivars showed intra-plant variation in cannabinoid concentration, while many had a consistent concentration regardless of canopy position. There was both intra- and inter-cultivar variation in architecture that correlated with intra-plant distribution of inflorescence biomass, and concentration of cannabinoids sampled from various positions within a plant. These relationships among morphological and biochemical traits will inform future decisions by cultivators, regulators, and plant breeders as well as our broader understanding of intra-plant variation of specialized biochemicals. HighlightIn-season hemp plant architecture measurements can predict post-harvest traits related to the distribution of biomass and concentration of cannabinoids.

plant biology↗

bioRxiv2022

Composition and Functional Properties of Hemp Seed Protein Isolates from Various Hemp Cultivars

Hemp seed protein isolates (HPI) were extracted from the seeds of seven commercial hemp cultivars, a Cornell breeding line, and a commercial hemp heart product. The composition and functional properties of the resulting HPI were investigated. HPI were of high protein purity >96% and contained various ratios of the major protein classes edestin, vicilin, and albumin, depending on the source. Protein solubility varied across HPI, and there was a positive correlation between greater levels of vicilin and albumin and improved solubility. The isoelectric points of HPI ranged from 5.50 to 5.94 but did not show significant effects associated with major protein class ratio. Significant differences in HPI foam capacity (52.9-84.9%), foam stability (68.1-89.4%), water holding capacity (0.83-1.05 g water/g protein isolate), and oil holding capacity (1.28-1.81 g oil/g protein isolate) were observed. In general, the emulsions generated from HPI performed poorly in terms of emulsifying activity, stability, and emulsion particle size. The ratio of edestin, vicilin, and albumin was found to play a major role in HPI functionality, suggesting that certain hemp cultivars may be better suited for generating protein ingredients that can functionalize plant-based foods.

biochemistry↗

bioRxiv2021

Morphometric relationships and their contribution to biomass and cannabinoid yield in hybrids of hemp (Cannabis sativa)

The breeding of hybrid cultivars of hemp (Cannabis sativa L.) is not well described, especially the segregation and inheritance of traits that are important for yield. A total of 23 families were produced from genetically diverse parents to investigate the inheritance of morphological traits and their association with biomass accumulation and cannabinoid yield. In addition, a novel classification method for canopy architecture was developed. The strong linear relationship between wet and dry biomass provided an accurate estimate of final dry stripped floral biomass. Of all field and aerial measurements, basal stem diameter was determined to be the single best selection criterion for final dry stripped floral biomass yield. Along with stem diameter, canopy architecture and stem growth predictors described the majority of the explainable variation of biomass yield. Within-family variance for morphological and cannabinoid measurements reflected the heterozygosity of the parents. While selfed populations suffered from inbreeding depression, hybrid development in hemp will require at least one inbred parent to achieve uniform growth and biomass yield. Nevertheless, floral phenology remains a confounding factor in selection because of its underlying influence on biomass production highlighting the need to understand the genetic basis for flowering time in the breeding of uniform cultivars. HighlightStem and canopy architecture traits are superior predictors of floral biomass yield and offer a good indication of hybrid uniformity in field plantings of genetically diverse cannabinoid hemp populations.

plant biology↗