Publications by authors named "Carolyn A Raymond"

7 Publications

  • Page 1 of 1

Complex Patterns of Cannabinoid Alkyl Side-Chain Inheritance in Cannabis.

Sci Rep 2019 08 6;9(1):11421. Epub 2019 Aug 6.

Southern Cross Plant Science, Southern Cross University, Lismore, New South Wales, 2480, Australia.

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 F progeny derived from a cross between two Cannabis chemotypes divergent for alkyl and cyclic cannabinoids. Inheritance patterns of F 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 F THCAS 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.
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http://dx.doi.org/10.1038/s41598-019-47812-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6684623PMC
August 2019

Remobilization and fate of sulphur in mustard.

Ann Bot 2019 10;124(3):471-480

Southern Cross Plant Science, Southern Cross University, Lismore, Australia.

Background And Aims: Sulphur (S) is an essential macronutrient involved in numerous metabolic pathways required for plant growth. Crops of the plant family Brassicaceae require more S compared with other crops for optimum growth and yield, with most S ultimately sequestered in the mature seeds as the storage proteins cruciferin and napin, along with the unique S-rich secondary metabolite glucosinolate (GSL). It is well established that S assimilation primarily takes place in the shoots rather than roots, and that sulphate is the major form in which S is transported and stored in plants. We carried out a developmental S audit to establish the net fluxes of S in two lines of Brassica juncea mustard where seed GSL content differed but resulted in no yield penalty.

Methods: We quantified S pools (sulphate, GSL and total S) in different organs at multiple growth stages until maturity, which also allowed us to test the hypothesis that leaf S, accumulated as a primary S sink, becomes remobilized as a secondary source to meet the requirements of GSL as the dominant seed S sink.

Key Results: Maximum plant sulphate accumulation had occurred by floral initiation in both lines, at which time most of the sulphate was found in the leaves, confirming its role as the primary S sink. Up to 52 % of total sulphate accumulated by the low-GSL plants was lost through senesced leaves. In contrast, S from senescing leaves of the high-GSL line was remobilized to other tissues, with GSL accumulating in the seed from commencement of silique filling until maturity.

Conclusion: We have established that leaf S compounds that accumulated as primary S sinks at early developmental stages in condiment type B. juncea become remobilized as a secondary S source to meet the demand for GSL as the dominant seed S sink at maturity.
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http://dx.doi.org/10.1093/aob/mcz101DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6798836PMC
October 2019

Seed glucosinolate yield is maximized by higher rates of sulfur nutrition than required for seed yield in condiment mustard (Brassica juncea L.).

PLoS One 2019 2;14(4):e0213429. Epub 2019 Apr 2.

Southern Cross Plant Science, Southern Cross University, Lismore, New South Wales, Australia.

Brassica crops require high amounts of inorganic sulfur (S) for optimum yield, and are characterized by the synthesis of S-rich glucosinolates (GSL). Although it is well established that seed and GSL yield can be increased by S fertilizer, the detailed relationship between S supply as primary source and the harvestable sinks of seed GSL and storage proteins is poorly understood. We tested the hypothesis that Brassica juncea mustard seed acts as a secondary S sink, and so require a higher rate of S to achieve maximum seed GSL compared to rates required to attain maximum seed biomass. Our experimental strategy involved comparing responses to available S for seed biomass, GSL, and protein. This was carried out in a protected environment using sand culture for a high-GSL condiment-type homozygous B. juncea genotype. A low-GSL canola-type was used as a control, in order to establish a base-line of response. Significantly more S was required to achieve maximum seed GSL than was required to achieve maximum seed mass. Total seed protein content was not significantly affected by increased S. The high-GSL line appeared to have an efficient mechanism of S supply to the secondary S sink, given the observed increase in seed S with increased S availability. From a practical point of view, increases in seed GSL with S availability suggests that S fertilizer rates should be optimized for maximum seed GSL yield, rather that optimizing for seed yield, as occurs for most other crops.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0213429PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6445519PMC
December 2019

Developmental Plasticity of the Major Alkyl Cannabinoid Chemotypes in a Diverse Genetic Resource Collection.

Front Plant Sci 2018 23;9:1510. Epub 2018 Oct 23.

Southern Cross Plant Science, Southern Cross University, Lismore, NSW, Australia.

is a chemically diverse domesticated plant genus which produces a unique class of biologically active secondary metabolites referred to as cannabinoids. The affinity and selectivity of cannabinoids to targets of the human endocannabinoid system depend on alkyl side chain length, and these structural-activity relationships can be utilized for the development of novel therapeutics. Accurate early screening of germplasm has the potential to accelerate selection of chemical phenotypes (chemotypes) for pharmacological exploitation. However, limited attempts have been made to characterize the plasticity of alkyl cannabinoid composition in different plant tissues and throughout development. A chemotypic diversity panel comprised of 99 individuals from 20 populations sourced from the Ecofibre Global Germplasm Collection (ecofibre.com.au and anandahemp.com) was used to examine alkyl cannabinoid variation across vegetative, flowering and maturation stages. A wide range of di-/tri-cyclic as well as C-/C-alkyl cannabinoid composition was observed between plants. Chemotype at the vegetative and flowering stages was found to be predictive of chemotype at maturation, indicating a low level of plasticity in cannabinoid composition. Chemometric cluster analysis based on composition data from all three developmental stages categorized alkyl cannabinoid chemotypes into three classes. Our results suggest that more extensive chemical and genetic characterization of the genepool could facilitate the metabolic engineering of alkyl cannabinoid chemotypes.
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http://dx.doi.org/10.3389/fpls.2018.01510DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6206272PMC
October 2018

Genotypic Variation in Wheat Flour Lysophospholipids.

Molecules 2017 May 31;22(6). Epub 2017 May 31.

Southern Cross Plant Science, Southern Cross University, Lismore, NSW 2480, Australia.

Lysophospholipids (LPLs) are the most abundant polar lipids in wheat endosperm and naturally complex with amylose, affecting starch physicochemical properties. We analyzed LPLs in wheat flour from 58 cultivars which differ by grain hardness using liquid chromatography mass spectrometry (LCMS). There were significant differences in LPL content between cultivars, demonstrating that genotype rather than environment contributes most to the total variance in wheat endosperm LPLs. Polar lipids such as LPLs may play a role in grain hardness through their interaction with puroindoline proteins, however, no strong correlation between kernel hardness and LPLs was detected. This may reflect the location of LPLs within the starch granule as opposed to the puroindoline proteins outside starch granules. LPLs may have an indirect relationship with kernel hardness as they could share the same origin as polar lipids that interact with puroindoline on the starch granule surface.
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http://dx.doi.org/10.3390/molecules22060909DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6152675PMC
May 2017

GC-MS method validation and levels of methyl eugenol in a diverse range of tea tree (Melaleuca alternifolia) oils.

Anal Bioanal Chem 2017 Mar 11;409(7):1779-1787. Epub 2017 Jan 11.

Australian Tea Tree Industry Association (ATTIA Ltd), PO Box 903, Casino, New South Wales, 2470, Australia.

Tea tree oil distilled from Melaleuca alternifolia has widespread use in the cosmetic industry as an antimicrobial as well as for other functions in topical products. Concerns were first raised by the European Commission's Scientific Committee on Consumer Products in 2004 about the level of the potentially carcinogenic phenylpropanoid compound methyl eugenol in tea tree oil. Limits on oil content in different types of cosmetic products were set based on a reported upper level of 0.9% methyl eugenol in the oil. A previous publication indicated that these levels were based on oil from a Melaleuca species not used in the commercial production of oil. Even the highest recorded levels in Melaleuca alternifolia, the overwhelmingly most common species used, were ∼15 times less than this, meaning that more oil could be safely used in the products. The current study, including details on methodology and reproducibility, extends that work across a suite of 57 plantation-sourced oils from a range of geographical locations and production years, as well as many Australian and international commercial oils. Lower levels of methyl eugenol in oils of known provenance were confirmed, with a recorded range of 160-552 ppm and a mean of 337 ppm. Analysis of variance showed methyl eugenol levels in Australian plantation oils to be correlated to the geographical region but not to the year of production. Average methyl eugenol levels in commercial oils were significantly lower, and these samples were divided into an authentic group and a group that were suspected of being adulterated based on an independent test. Authentic commercial oils had similar levels of methyl eugenol to Australian provenance material, whilst the oils classed as suspect had significantly lower levels.
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http://dx.doi.org/10.1007/s00216-016-0134-4DOI Listing
March 2017

Novel Applications for Oxalate-Phosphate-Amine Metal-Organic-Frameworks (OPA-MOFs): Can an Iron-Based OPA-MOF Be Used as Slow-Release Fertilizer?

PLoS One 2015 3;10(12):e0144169. Epub 2015 Dec 3.

Southern Cross Plant Science, Southern Cross University, Lismore, NSW, 2480, Australia.

A porous iron-based oxalate-phosphate-amine metal-organic framework material (OPA-MOF) was investigated as a microbially-induced slow-release nitrogen (N) and phosphorus (P) fertilizer. Seedling growth, grain yields, nutrient uptake of wheat plants, and soil dynamics in incubated soil, were investigated using OPA-MOF vs standard P (triple-superphosphate) and N (urea) fertilizers in an acidic Ferralsol at two application rates (equivalent 120 and 40 kg N ha(-1)). While urea hydrolysis in the OPA-MOF treatment was rapid, conversion of ammonium to nitrate was significantly inhibited compared to urea treatment. Reduced wheat growth in OPA-MOF treatments was not caused by N-deficiency, but by limited P-bioavailability. Two likely reasons were slow P-mobilisation from the OPA-MOF or rapid P-binding in the acid soil. P-uptake and yield in OPA-MOF treatments were significantly higher than in nil-P controls, but significantly lower than in conventionally-fertilised plants. OPA-MOF showed potential as enhanced efficiency N fertilizer. However, as P-bioavailability was insufficient to meet plant demands, further work should determine if P-availability may be enhanced in alkaline soils, or whether central ions other than Fe, forming the inorganic metal-P framework in the MOF, may act as a more effective P-source in acid soils.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0144169PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4669090PMC
June 2016