79 research outputs found

    Multi-omics approaches to study molecular mechanisms in Cannabis sativa

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    Cannabis (Cannabis sativa L.), also known as hemp, is one of the oldest cultivated crops, grown for both its use in textile and cordage production, and its unique chemical properties. However, due to the legislation regulating cannabis cultivation, it is not a well characterized crop, especially regarding molecular and genetic pathways. Only recently have regulations begun to ease enough to allow more widespread cannabis research, which, coupled with the availability of cannabis genome sequences, is fuelling the interest of the scientific community. In this review, we provide a summary of cannabis molecular resources focusing on the most recent and relevant genomics, transcriptomics and metabolomics approaches and investigations. Multi-omics methods are discussed, with this combined approach being a powerful tool to identify correlations between biological processes and metabolic pathways across diverse omics layers, and to better elucidate the relationships between cannabis sub-species. The correlations between genotypes and phenotypes, as well as novel metabolites with therapeutic potential are also explored in the context of cannabis breeding programs. However, further studies are needed to fully elucidate the complex metabolomic matrix of this crop. For this reason, some key points for future research activities are discussed, relying on multi-omics approaches

    Genome-wide analysis of Dof genes and their response to abiotic stress in rose (Rosa chinensis)

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    Dof (DNA binding with one finger) proteins play important roles in plant development and defense regulatory networks. In the present study, we report a genome-wide analysis of rose Dof genes (RchDof), including phylogenetic inferences, gene structures, chromosomal locations, gene duplications, and expression diversity. A total of 24 full-length RchDof genes were identified in Rosa chinensis, which were assigned to nine distinct subgroups. These RchDof genes were unevenly distributed on rose chromosomes. The genome-scale analysis of synteny indicated that segmental duplication events may have played a major role in the evolution of the RchDof gene family. Analysis of cis-acting elements revealed putative functions of Dofs in rose during development as well as under numerous biotic and abiotic stress conditions. Moreover, the expression profiles derived from qRT-PCR experiments demonstrated distinct expression patterns in various tissues, and gene expression divergence existed among the duplicated RchDof genes, suggesting a fundamentally functional divergence of the duplicated Dof paralogs in rose. The gene expression analysis of RchDofs under drought and salt stress conditions was also performed. The present study offered novel insights into the evolution of RchDofs and can aid in the further functional characterization of its candidate genes

    Molecular mechanisms underlying potential pathogen resistance in cannabis sativa

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    Cannabis (Cannabis sativa L.) is one of the earliest cultivated crops, valued for producing a broad spectrum of compounds used in medicinal products and being a source of food and fibre. Despite the availability of its genome sequences, few studies explore the molecular mechanisms involved in pathogen defense, and the underlying biological pathways are poorly defined in places. Here, we provide an overview of Cannabis defence responses against common pathogens, such as Golovinomyces spp., Fusarium spp., Botrytis cinerea and Pythium spp. For each of these pathogens, after a summary of their characteristics and symptoms, we explore studies identifying genes involved in Cannabis resistance mechanisms. Many studies focus on the potential involvement of disease-resistance genes, while others refer to other plants however whose results may be of use for Cannabis research. Omics investigations allowing the identification of candidate defence genes are highlighted, and genome editing approaches to generate resistant Cannabis species based on CRISPR/Cas9 technology are discussed. According to the emerging results, a potential defence model including both immune and defence mechanisms in Cannabis plant–pathogen interactions is finally proposed. To our knowledge, this is the first review of the molecular mechanisms underlying pathogen resistance in Cannabis

    Preliminary evidence for the role played by south westerly wind strength on the marine diatom content of an Antarctic Peninsula ice core (1980–2010)

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    Winds in the Southern Ocean drive exchanges of heat and carbon dioxide between the ocean and atmosphere. Wind dynamics also explain the dominant patterns of both basal and surface melting of glaciers and ice shelves in the Amundsen and Bellingshausen Seas. Long records of past wind strength and atmospheric circulation are needed to assess the significance of these recent changes. Here we present evidence for a novel proxy of past south westerly wind (SWW) strength over the Amundsen and Bellingshausen Seas, based on diatoms preserved in an Antarctic Peninsula ice core. Ecological affinities of the identified diatom taxa indicate an almost exclusively marine assemblage, dominated by open ocean taxa from the Northern Antarctic Zone (NAZ). Backtrajectory analysis shows the routes of air masses reaching the ice core site and reveals that many trajectories involve contact with surface waters in the NAZ of the Amundsen and Bellingshausen Seas. Correlation analyses between ice core diatom abundance and various wind vectors yield positive and robust coefficients for the 1980–2010 period, with average annual SWW speeds exhibiting the strongest match. Collectively, the data presented here provide new evidence that diatoms preserved in an Antarctic Peninsula ice core offer genuine potential as a new proxy for SWW strength

    Transcriptome analysis reveals candidate genes for dietary fiber metabolism in Rosa roxburghii fruit grown under different light intensities

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    The fruit of the perennial rosebush Rosa roxburghii were valued for their high levels of ascorbic acid, superoxide dismutase activity, and cancer preventing effects. The high cellulose and low pectin content of Rosa roxburghii fruit results in an undesirable fibrous texture and hence needs to be addressed. However, little is known about the molecular mechanisms underlying dietary fiber metabolism in this fruit. Here, we report that the contents of cellulose, pectin, and lignin were increased by shading treatments at the maturation stage of fruit development. Under 50% shading, the soluble pectin content increased by 16.39%, which may improve the fruit palatability. However, deeper shading of 100% caused the lignin content to increase by 28.86%, which conversely may lower fruit quality. Based on transcriptome analysis, we identified candidate genes involved in dietary fiber metabolism, including cellulose synthase (CesA) 1, 2, 3, and 5, â-1,4-xylosyltransferase (IRX), arabinosyltransferase (ARAD) 1 and 2, galacturonosyltransferase (GAUT), cellulolytic enzyme (Cx), and pectin methylesterase, in which CesA1, CesA2, CesA3, IRX, ARAD2, and GAUT3 significantly responded to shading and positively correlated with the content of their corresponding component. Furthermore, cinnamyl alcohol dehydrogenase was significantly regulated by shading treatment and positively correlated with increasing lignin concentration. These results may facilitate a better understanding of the molecular mechanisms of dietary fiber metabolism in R. roxburghii fruit under low light conditions and provide a framework for future crop improvement

    Overexpression of RrGGP2 and RrDHAR increases ascorbic acid content in tomato

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    Ascorbic acid (AsA) is the most abundant antioxidant in plants and is an important nutritional index for agricultural products. Some plants, such as Rosa roxburghii Tratt., contain exceptionally high levels of AsA, but are relatively unpalatable. In view of its role in human health, as well as plant growth and development, we examined the effects of two important AsA regulatory genes from R. roxburghii in tomato, with the aim of producing a crop of higher nutritional quality. RrGGP2 and RrDHAR were cloned from R. roxburghii fruit. The overexpression vectors were made using 35S promoters and mediated by Agrobacterium tumefaciens to obtain the overexpression lines. A PCR and qRT-PCR verified that the two genes had been inserted and overexpressed in the tomato leaves and fruits. The results showed that the overexpression of RrGGP2 increased tomato leaf and fruit AsA content by 108.5% and 294.3%, respectively, while the overexpression of RrDHAR increased tomato leaf and fruit AsA content by 183.9% and 179.9%. The overexpression of RrGGP2 and RrDHAR further changed the expression of genes related to AsA metabolism, and the upregulation of one such gene, SlGGP, may have contributed greatly to the increase in AsA. Results here indicate that RrGGP2 contributes more towards fruit AsA accumulation in tomato than RrDHAR

    Postharvest exogenous melatonin treatment of strawberry reduces postharvest spoilage but affects components of the aroma profile

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    BACKGROUND: Strawberries are perishable fruits that decay quickly after harvest, but are valued for their distinctive taste and aroma. Melatonin is involved in plant resistance against stress, plant senescence and fruit ripening, and was shown to delay post-harvest spoilage of strawberries. OBJECTIVE: The effects of melatonin postharvest treatment on shelf-life and volatile organic compound profile were assessed in strawberry fruits cv “Luca”. METHODS: Strawberry fruit were treated with 100 μM melatonin and stored at 4°C for 12 days to assess whether melatonin treatment could delay spoilage without adversely affecting aroma. RESULTS: Melatonin treatment delayed fruit deterioration by reducing weight loss and incidence of decay as well as maintaining total soluble solids, titratable acidity, anthocyanin, and taste. Melatonin treatment also significantly reduced CO2 production compared to control fruits. The relative abundance of the majority of volatile organic compounds (VOCs) was not affected, however abundance of two VOCs that are important components of strawberry aroma were affected by melatonin treatment. CONCLUSIONS: Post-harvest treatment of strawberries with 100 μM melatonin improved strawberry quality and conserved bioactive compounds after 12 d of storage. However, components of the aroma profile were altered in a way which may affect consumer perception of quality

    Contrastive analysis of trichome distribution, morphology, structure, and associated gene expression reveals the formation factors of different trichome types in two commercial Rosa species

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    Trichomes are prevalent on the surfaces of many organs in Rosa and have an important impact on the edibility of the fruit. Here, the diversity, distribution, anatomical structure, and genetic regulation of trichomes in Rosa roxburghii Tratt. (RR) and R. sterilis S. D. Shi (RS) were explored. RS and RR are important commercial crops in China due to their nutritional and medicinal value; however, their consumption and utilization are limited, in part, by the abundance of trichomes on the fruit. Two main forms of trichomes were present in both germplasms, namely glandular and non-glandular trichomes. Non-glandular flagellate and acicular trichomes were observed on the sepals, fruit, major leaf veins, and pedicels of both germplasms, whereas non-glandular branched trichomes were present only on RS. Flagellate trichome exfoliation and acicular trichome lignification occurred gradually on the developing fruit. Capitate glandular and bowl-shaped glandular trichomes were abundant in RS, but were only observed on the major leaf veins of RR. Furthermore, some capitate glandular trichomes on the pedicels were found to develop into prickles in RS. Transmission electron microscopy indicated that vacuolation and in the extraplasmic space occurred in the glandular cells of the capitate trichomes at the late secretory stage. The prickles in RR and RS mainly consisted of lignin, suberin, cellulose, and hemicellulose, though the ratios of these constituents varied between species. The expression levels of several well-known core trichome regulatory genes varied depending on the trichome type. The transcript abundance of GL1, GL2, and TTG1 was significantly higher in organs covered with acicular trichomes in both RR and RS, while the highest mRNA level of TRY was observed in the glabrous organs, suggesting a negative effect of this gene on trichome formation. Notably, the negative regulatory factor CPC was only highly expressed in the leaf mesophyll of RR, where no glandular trichomes were present, and the GL3, PDF2-like, and CPC transcription factors co-regulated glandular trichome formation in RS. The expression of these genes peaked in the Fb3-stage buds of RR and B3-stage buds of RS, indicating different key phases for the regulation of trichome initiation. These data provide new insights into the genetic control of trichome formation in two Rosa species

    Comparative ultrastructure of trichomes on various organs of Rosa roxburghii

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    Chestnut rose, R. roxburghii Tratt. (Rosaceae) (RR) is an important crop in China due to its nutritional and medicinal values. RR frequently produces trichomes on the surfaces of a diverse range of organs, however a genetic component exists to the control of trichome development, with some cultivars having significantly fewer trichomes to others. Certain varieties have fruits that are thickly covered with macroscopic trichomes, which is an undesirable trait for fruit processing and consumption. However, smooth-fruit cultivars exist, such as R. roxburghii Tratt. f. esetosa Ku (RRE). Despite their economic importance, the anatomical features of trichomes have not been explored in detail for these two chestnut rose germplasms. Here, we investigate the ultrastructure of trichomes distributed on the stem, sepal, and fruit of RR and RRE using transmission electron microscopy (TEM). The internal structure of stem prickle trichomes in RR and RRE was oval in shape and did not contain nucleoli or other organelles. The cell walls of stem prickles in RR are thick and the intercellular spaces occupied with liquid, whereas the cells wall of stem prickles in RRE are thin and have air-filled intercellular spaces. The cells of sepal acicular trichomes in RR and glandular trichomes (GTs) of sepals in RRE had similar vacuole sizes, cytoplasm content, intercellular spaces, and arrangement of plastids within cells. However, there were osmiophilic granules present in the GTs of RRE. The flagelliform trichomes in the sepals of the two germplasms are composed of oval or rod-shaped cells. Although the flagelliform trichomes in the sepals of the two germplasms had a similar internal structure, and both contained starch grains and plastids with visible thylakoid membranes, the flagelliform trichomes in the sepals of RR had a thinner cell wall and a higher proportion of cytoplasm which was more evenly distributed across the cell. There were granules that stained heavily with osmium tetroxide which occurred infrequently in the flagelliform trichomes of sepals in RRE but were not observed in RR. On the acicular trichomes of fruit in RR, the flagelliform trichomes and the GTs of fruit in RRE shared similar cell morphology, arrangement and vacuole size as well as intercellular space. Both the fruit flagelliform trichomes and GTs in RRE contain granules which stain heavily with osmium tetroxide, and the GTs contain plastids and starch grains. These differences in trichome cell ultrastructure may be related to developmental processes or biological functions of the trichomes. These results also suggest that the two chestnut rose germplasms are good candidates for further study of trichome ontogeny in the genus and subsequent breeding of the smooth organ trait in this species
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