Exploring the mechanism of Lycium barbarum fruit cell wall polysaccharide remodeling reveals potential pectin accumulation contributors.

The level of polysaccharides in the mature Lycium barbarum fruit (LBF) cell wall depends on their metabolism, trafficking, and reassembly within the cell. In this study, we examined the composition, content, and ultrastructure of the cell wall polysaccharides of LBF during maturation, and further analyzed cell wall polysaccharide remodeling using isotope tagging with relative and absolute quantification (iTRAQ)-based proteomics. The results showed that the contents of cellulose and hemicellulose tended to increase in the pre-maturation stage and decrease in the later stage, while pectin level increased before fruit maturing. The differential expression of the 54 proteins involved in the metabolic pathways for glucose, fructose, galactose, galacturonic acid and arabinose was found to be responsible for these alterations. The work provides a biological framework for the reorganization of polysaccharides in the LBF cell wall, and supports the hypothesis that pectic polysaccharide glycosyl donors come from starch, cellulose, hemicellulose and isomorphic pectin.

Melatonin treatment delays the softening of blueberry fruit by modulating cuticular wax metabolism and reducing cell wall degradation.

The effects of postharvest melatonin (MT) treatment on cuticular wax and cell wall metabolism in blueberry fruit (Vaccinium spp.) were evaluated. The results revealed that MT treatment maintained the cuticular wax rod-like structure and delayed wax degradation. The gas chromatography-mass spectrometry analysis results revealed that MT application changed the cuticular wax composition in blueberries, and 25 metabolic components were screened. The metabolic regulation of wax quality in blueberry fruit may therefore be influenced by MT. Additionally, MT slowed down pectin and cellulose degradation by reducing the activities of cell wall degrading enzymes like pectin methyl esterase polygalacturonase, ß-galactosidase, and cellulose in the later stages of storage. It also downregulated the transcriptional expression of related genes like VcPE, VcPG, VcBG6, and VcGAL1. Thus, MT prevented softening and senescence by postponing the degradation of the cell wall in postharvest blueberry fruit.

A multimodal and multiscale investigation of factors affecting the juice yield of cider apples.

Apple cider juice yield at harvest and after 15 and 30 days of storage durations was studied by analyzing the mechanical properties of fresh and plasmolyzed flesh, water distribution, cell wall polysaccharide composition and organization of the apples; in this study, the apple varieties used were Avrolles, Douce coetligne, Douce moen, Judor, Petit jaune. Juice yield mainly depended on the apple variety and the storage duration. Cellulose organization and cell wall pectin hydration were affected by ripening and are related to fruit firmness. Flesh viscoelastic mechanical properties were not general indications of juice yields. However, these properties helped distinguish the varieties according to flesh damage caused by ice crystals upon freezing. Cell encapsulation of the juice in the flesh contributed to lower yields. The apple variety and harvesting mode are recommended as a means to better control juice yield variations.

Effects of cellulose nanofibrils treatment on antioxidant properties and aroma of fresh-cut apples.

Horticultural products tend to deteriorate during postharvest storage and processing. In this study, cellulose nanofibers (CNFs) were prepared from wood to investigate the effects of CNF treatment on the storage quality, aroma composition, and antioxidant system of fresh-cut apple (Malus domestica) wedges. Compared with control treatment, CNF coating treatment significantly improved the appearance of apple wedges; reduced the decay rate of apple wedges; and delayed the decline in weight loss, firmness, and titratable acid during storage. Gas chromatography-mass spectrometry showed that CNF treatment could maintain the aroma components of apple wedges (stored for 4 days). Further investigations showed that CNF treatment increased the antioxidant system level and decreased reactive oxygen species content and membrane lipid peroxidation level of apple wedges. Overall, this study showed that CNF coating could effectively maintain the quality of fresh-cut apples during cold storage.

A dive into the cell wall with Arabidopsis.

One of the many legacies of the work of Michel Caboche is our understanding of plant cell wall synthesis and metabolism thanks to the use of Arabidopsis mutants. Here I describe how he was instrumental in initiating the genetic study of plant cell walls. I also show, with a few examples for cellulose and pectins, how this approach has led to important new insights in cell wall synthesis and how the metabolism of pectins contributes to plant growth and morphogenesis. I also illustrate the limitations of the use of mutants to explain processes at the scale of cells, organs or whole plants in terms of the physico-chemical properties of cell wall polymers. Finally, I sketch how new approaches can cope with these limitations.

L'un des nombreux héritages des travaux de Michel Caboche est notre compréhension de la synthèse et du métabolisme des parois cellulaires végétales grâce à l'utilisation de mutants d'Arabidopsis. Je décris ici comment il a joué un rôle déterminant dans le lancement de l'étude génétique des parois cellulaires végétales. Je montre également, avec quelques exemples pour la cellulose et les pectines, comment cette approche a conduit à de nouvelles connaissances importantes sur la synthèse de la paroi cellulaire et comment le métabolisme des pectines contribue à la croissance et à la morphogenèse des plantes. J'illustre également les limites de l'utilisation de mutants pour expliquer des processus à l'échelle de cellules, d'organes ou de plantes entières en termes de propriétés physico-chimiques de polymères de parois cellulaires. Enfin, j'esquisse comment de nouvelles approches peuvent faire face à ces limitations.

Pulvinar slits: Cellulose-deficient and de-methyl-esterified pectin-rich structures in a legume motor cell.

The cortical motor cells (CMCs) in a legume pulvinus execute the reversible deformation in leaf movement that is driven by changes in turgor pressure. In contrast to the underlying osmotic regulation property, the cell wall structure of CMCs that contributes to the movement has yet to be characterized in detail. Here, we report that the cell wall of CMCs has circumferential slits with low levels of cellulose deposition, which are widely conserved among legume species. This structure is unique and distinct from that of any other primary cell walls reported so far; thus, we named them "pulvinar slits." Notably, we predominantly detected de-methyl-esterified homogalacturonan inside pulvinar slits, with a low deposition of highly methyl-esterified homogalacturonan, as with cellulose. In addition, Fourier transform infrared spectroscopy analysis indicated that the cell wall composition of pulvini is different from that of other axial organs, such as petioles or stems. Moreover, monosaccharide analysis showed that pulvini are pectin-rich organs like developing stems and that the amount of galacturonic acid in pulvini is greater than in developing stems. Computer modeling suggested that pulvinar slits facilitate anisotropic extension in the direction perpendicular to the slits in the presence of turgor pressure. When tissue slices of CMCs were transferred to different extracellular osmotic conditions, pulvinar slits altered their opening width, indicating their deformability. In this study, we thus characterized a distinctive cell wall structure of CMCs, adding to our knowledge of repetitive and reversible organ deformation as well as the structural diversity and function of the plant cell wall.

Valorisation of fruit peel bioactive into green synthesized silver nanoparticles to modify cellulose wrapper for shelf-life extension of packaged bread.

Fruit peels are rich source of bioactive compounds such as polyphenols, flavonoids, and antioxidants but are often discarded as waste due to limited pharmaceutical and nutraceutical applications. This study aimed to valorise pomegranate and citrus fruit peel into green synthesised silver nanoparticles (AgNPs) in order to modify cellulose-based wrapping material for prospective food packaging applications and propose an alternate and sustainable approach to replace polyethene based food packaging material. Four different concentrations of AgNO3 (0.5 mM, 1 mM, 2 mM, and 3 mM) were used for green synthesis of AgNPs from fruit peel bioactive, which were characterised followed by phytochemical analysis. Ultraviolet-Visible spectroscopy showed surface plasmon resonance at 420 nm, XRD analysis showed 2θ peak at 27.8°, 32.16°, 38.5°, 44.31°, 46.09°, 54.76°, 57.47°, 64.61° and 77.50° corresponding to (210), (122), (111), (200), (231), (142), (241), (220) and (311) plane of face centred cubic crystal structure of AgNPs. Fourier-transform infrared spectroscopy analysis of AgNPs green synthesised from pomegranate and kinnow peel extract showed a major peak at 3277, 1640 and 1250-1020 1/cm while a small peak at 2786 1/cm was observed in case of pomegranate peel extract which was negligible in AgNPs synthesized from kinnow peel extract. Particle sizes of AgNPs showed no statistically significant variance with p > 0.10 and thus, 2 mM was chosen for further experimentation and modification of cellulose based packaging material as it showed smallest average particle size. Zeta potential was observed to be nearly neutral with a partial negative strength due to presence of various phenolic compounds such as presence of gallic acid which was confirmed by ultrahigh performance liquid chromatography-photodiode array(UHPLC-PDA) detector. Thermal stability analysis of green synthesised AgNPs qualified the sterilisation conditions up to 100 °C. AgNPs green synthesized from both the peel extracts had higher polyphenolic content, antioxidant and radical scavenging activity as compared to peel extracts without treatment (p < 0.05). The cellulose based food grade packaging material was enrobed by green synthesised AgNPs. The characterisation of modified cellulose wrappers showed no significant difference in thickness of modified cellulose wrappers as compared with untreated cellulose wrapper (p > 0.42) while weight and grammage increased significantly in modified cellulose wrapper (p < 0.05). The colour values on CIE scale (L*, a* and b*) showed statistically significant increase in yellow and green colour (p < 0.05) for modified cellulose wrappers as compared to control wrapper. The oxygen permeability coefficient, water vapour permeability coefficient, water absorption capacity and water behaviour characteristics (water content, swelling degree and solubility) showed significant decrease (p < 0.05) for modified cellulose wrapper as compared to control wrapper. A uniform distribution and density of green synthesised AgNPs across cellulose wrapper matrix was observed through scanning electron microscopy (SEM) images with no significant aggregation, confirming successful enrobing and stable immobilisation of nanoparticles from cellulose matrix. A seven-day storage study of bread wrapped in modified and control cellulose wrappers showed delayed occurrence of microbial, yeast and mould count in bread packaged in modified cellulose wrappers and thus, resulting in shelf life extension of bread. The results are encouraging for the potential applications of modified cellulose wrappers to replace polyethene based food packaging.

Characterization of Bacterial Cellulose Produced by Acetobacter xylinum Strain LKN6 Using Sago Liquid Waste as Nutrient Source.

<b>Background and Objective:</b> Bacterial Cellulose (BC) is an exopolysaccharide produced by bacteria with unique structural and mechanical properties and is highly pure compared to plant cellulose. This study aimed to produce novel bacterial cellulose using sago liquid waste substrate and evaluate its characteristics as a potential bioplastic.<b>Materials and Methods:</b> Production of BC by static batch fermentation was studied in sago liquid waste substrate usingAcetobacter xylinumLKN6. The BC structure was analyzed by Scanning Electron Microscopy (SEM) and Fourier Transform infrared spectroscopy (FT-IR). Mechanical properties were measured include tensile strength, elongation at break, elasticity (Young's modulus) and Water Holding Capacity (WHC). <b>Results:</b> The BC yield from sago liquid waste as a nutrients source was achieved 12.37 g L¹ and the highest BC yield 14.52 g L¹ in sago liquid waste medium with a sugar concentration of 10% (w/v) after 14 days fermentation period. The existence of bacterial cellulose is proven by FT-IR spectroscopy analysis based on the appearance of absorbance peaks, which are C-C bonding, C-O bonding, C-OH bonding and C-O-C bonding and represents the fingerprints of pure cellulose. The mechanical properties of BC from sago liquid waste were showed a tensile strength of 44.2-87.3 MPa, elongation at break of 4.8-5.8%, Young's Modulus of 0.86-1.64 GPa and water holding capacity of 85.9-98.6 g g¹. <b>Conclusion:</b> The results suggest that sago liquid waste has great potential to use as a nutrient source in the production of bacterial cellulose and BC's prospect as the bioplastic.

The role of cell wall polysaccharides disassembly in Lasiodiplodia theobromae-induced disease occurrence and softening of fresh longan fruit.

Cell wall polysaccharides in fruits act a pivotal role in their resistance to fungal invasion. Lasiodiplodia theobromae (Pat.) Griff. & Maubl. is a primary pathogenic fungus causing the spoilage of fresh longan fruit. In this study, the influences of L. theobromae inoculation on the disassembly of cell wall polysaccharides in pericarp of fresh longans and its association with L. theobromae-induced disease and softening development were investigated. In contrast to the control, samples with L. theobromae infection showed more severe disease development, lower firmness, lower amounts of cell wall materials, covalent-soluble pectin, ionic-soluble pectin, cellulose and hemicellulose, whereas higher value of water-soluble pectin, higher activities of cell wall polysaccharide-disassembling enzymes (cellulase, ß-galactosidase, polygalacturonase and pectinesterase). These findings revealed that cell wall polysaccharides disassembly induced by enzymatic manipulation was an essential pathway for L. theobromae to infect harvested longans, and thus led to the disease occurrence and fruit softening.

Perennial halophyte Salicornia neei Lag.: Cell wall composition and functional properties of its biopolymers.

Salicornia neei halophyte extends in Argentina seashores. To envisage potential applications, cell wall sequential extraction performed on dry plant yielded 1.1, 2.4, 0.3 and 0.9% of pectin fractions respectively extracted by room temperature water, 90 °C-water, CDTA and Na2CO3. They contained 21-33% uronic acids (UA) with low degree of methylation and 0.5-1.2 M ratios of neutral sugars to UA. High arabinose level suggests that long arabinan side-chains maintain cell wall flexibility in water deficit. Fractions also contained 10-36% of proteins. The KOH-soluble fractions (4.3%) were mainly arabinoxylans. At 2.0% w/v, pectin fractions developed "weak gel"-type networks with Ca2+, while arabinoxylans generated "dilute solutions". Cellulose (28%) and lignin (45.1%) were the main biopolymers in the final residue, which showed low water swelling capacity (3.6 mL/g) due to lignin, increasing when arabinoxylans were also present. Phenolics (9.8%) were mainly water-extractable. Salicornia is a source of biopolymers and antioxidants potentially useful for food applications.

Comparative cellular, physiological and transcriptome analyses reveal the potential easy dehulling mechanism of rice-tartary buckwheat (Fagopyrum Tararicum).

BACKGROUND: Tartary buckwheat has gained popularity in the food marketplace due to its abundant nutrients and high bioactive flavonoid content. However, its difficult dehulling process has severely restricted its food processing industry development. Rice-tartary buckwheat, a rare local variety, is very easily dehulled, but the cellular, physiological and molecular mechanisms responsible for this easy dehulling remains largely unclear. RESULTS: In this study, we integrated analyses of the comparative cellular, physiological, transcriptome, and gene coexpression network to insight into the reason that rice-tartary buckwheat is easy to dehull. Compared to normal tartary buckwheat, rice-tartary buckwheat has significantly brittler and thinner hull, and thinner cell wall in hull sclerenchyma cells. Furthermore, the cellulose, hemicellulose, and lignin contents of rice-tartary buckwheat hull were significantly lower than those in all or part of the tested normal tartary buckwheat cultivars, respectively, and the significant difference in cellulose and hemicellulose contents between rice-tartary buckwheat and normal tartary buckwheat began at 10 days after pollination (DAP). Comparative transcriptome analysis identified a total of 9250 differentially expressed genes (DEGs) between the rice- and normal-tartary buckwheat hulls at four different development stages. Weighted gene coexpression network analysis (WGCNA) of all DEGs identified a key module associated with the formation of the hull difference between rice- and normal-tartary buckwheat. In this specific module, many secondary cell wall (SCW) biosynthesis regulatory and structural genes, which involved in cellulose and hemicellulose biosynthesis, were identified as hub genes and displayed coexpression. These identified hub genes of SCW biosynthesis were significantly lower expression in rice-tartary buckwheat hull than in normal tartary buckwheat at the early hull development stages. Among them, the expression of 17 SCW biosynthesis relative-hub genes were further verified by quantitative real-time polymerase chain reaction (qRT-PCR). CONCLUSIONS: Our results showed that the lower expression of SCW biosynthesis regulatory and structural genes in rice-tartary buckwheat hull in the early development stages contributes to its easy dehulling by reducing the content of cell wall chemical components, which further effects the cell wall thickness of hull sclerenchyma cells, and hull thickness and mechanical strength.

The Mechanism of Extraction of Peanut Protein and Oil Bodies by Enzymatic Hydrolysis of the Cell Wall.

Degradation of the peanut cell wall is a critical step in the aqueous enzymatic extraction process to extract proteins and oil bodies. Viscozyme® L, a compound cell wall degrading enzyme, has been applied as an alternative to protease in the process of aqueous enzymatic extraction, but the mechanism of cell wall enzymolysis remains unclear. The present study aims to investigate the changes in cellulose, hemicellulose, and pectin content of the peanut cell wall hydrolyzed by Viscozyme® L. The degree to which the main components of the peanut cell wall, such as trans-1, 2-cyclohexanediamine-N,N,N',N'-acetic acid-soluble pectin (CDTA-soluble pectin), Na2CO3-soluble pectin, cellulose, and hemicellulose, are degraded is closely related to the extraction of oil bodies and peanut protein at different solid-liquid ratio of powered peanut seed in distilled water, enzyme concentration, enzyme hydrolysis temperature, and enzyme hydrolysis time. The key sites of Viscozyme® L activity on cell wall polysaccharides were explored by comparing the changes in chemical bonds under different extraction conditions using Fourier-transform infrared spectroscopy (FT-IR) absorption bands and principal component analysis (PCA). Viscozyme® L acted on the C-O stretching, C-C stretching, and CH2 symmetrical bending of cellulose, the C-O stretching and O-C-O asymmetrical bending of hemicellulose, and the C-O stretching and C-C stretching of pectin.

Ultrasound-assisted alkali-urea pre-treatment of Miscanthus × giganteus for enhanced extraction of cellulose fiber.

Ultrasound-assisted-alkali-urea (UAAU) pre-treatment of miscanthus biomass was investigated for enhanced delignification and extraction of cellulose fiber. The effects of pre-treatment conditions investigated were: sonication time (10.0, 15.0 and 20.0 min), alkali (NaOH) concentration (2.0, 3.5 and 5.0 %, w/v) and urea-concentration (1.0, 1.75 and 2.5 %, w/v) on the delignification and cellulose content. The process parameters were studied and optimized using a response surface methodology (RSM) based on the Box Behnken Design (BBD). From the RSM-BBD analysis, he optimized pre-treatment conditions were 2.1 % NaOH, 1.7 % urea and 15.5-min sonication time with maximal cellulose and lignin contents of 47.8 % (w/w) and 27.5 % (w/w) respectively. The pre-treated samples were further characterized by FTIR, colorimeter, SEM, XRD, and TGA analyses. The UAAU pre-treated samples have higher delignification and cellulose contents than the AU pre-treatment without sonication. Furthermore, the ultrasound process allowed selective removal of lignin without substantially degrading the functionalities of cellulose fiber. The UAAU pre-treated samples exhibited higher thermal stability, fibrillation, crystallinity index and smaller crystallite size.

Synthesis and characterization of starch nanocellulosic films incorporated with Eucalyptus globulus leaf extract.

Carrot cellulose nano fibers (CNF) have been extracted from carrot pulp using acid hydrolysis process. The size of the CNF was in the range of 6.33-58.77 nm. Starch nano-composite films were manufactured using varying concentration of CNF (5%, 10%, 15%, 20%) and mechanical properties of the films were studied at relative humidity 50% and 75%. Nano-composite films were manufactured using Eucalyptus globulus leafs extract (1%, 2%, 3%, 4%). Physio-chemical properties, antioxidant, antimicrobial, morphological and crystalline properties of the films were studied. Nano-composite films with 4% Eucalyptus globulus leafs extract was best to provide better barrier, antioxidant properties to grapes when wrapped and stored at room temperature (25 ± 2)°C for 7 days and refrigerator temperature (4 ± 1)°C for 28 days. Wrapped grapes with NCC/Eucalyptus globulus leaf extract stored for 28 days either at 25 °C or 4 °C had bacterial surface loads reduced up to 5 orders of magnitude compared to non-wrapped samples and had 4 orders of magnitude less bacterial surface loads than at the beginning of the experiments. Wrapped grapes with NCC/Eucalyptus globulus leaf extract significantly reduced the growth of Escherichia coli, Listeria monocytogenes, Salmonella typhimurium and Penicillium spp. when the cells of these organisms were spiked onto grapes and the samples were stored either at (25 ± 2) °C or (4 ± 1) °C for 28 days. The results showed that nano-composite with 4% Eucalyptus globulus leafs extract films have immense potential as food packaging/wrapping material.

Imaging and Analysis of the Content of Callose, Pectin, and Cellulose in the Cell Wall of Arabidopsis Pollen Tubes Grown In Vitro.

To achieve fertilization, pollen tubes have to protect and properly deliver sperm cells through the pistil to the ovules. Pollen tube growth is a representative example of polarized growth where new components of the cell wall and plasma membrane are continuously deposited at the tip of the growing cell. The integrity of the cell wall is of fundamental importance to maintain apical growth. For this reason, pollen tube growth has become an excellent model to study the role of polysaccharides and structural cell wall proteins involved in polar cell expansion. However, quantification of structural polysaccharides at the pollen tube cell wall has been challenging due to technical complexity and the difficulty of finding specific dyes. Here, we propose simple methods for imaging and quantification of callose, pectin , and cellulose using specific dyes such as Aniline Blue, Propidium Iodide, and Pontamine Fast Scarlet 4B.

Direct evidence of Neanderthal fibre technology and its cognitive and behavioral implications.

Neanderthals are often considered as less technologically advanced than modern humans. However, we typically only find faunal remains or stone tools at Paleolithic sites. Perishable materials, comprising the vast majority of material culture items, are typically missing. Individual twisted fibres on stone tools from the Abri du Maras led to the hypothesis of Neanderthal string production in the past, but conclusive evidence was lacking. Here we show direct evidence of fibre technology in the form of a 3-ply cord fragment made from inner bark fibres on a stone tool recovered in situ from the same site. Twisted fibres provide the basis for clothing, rope, bags, nets, mats, boats, etc. which, once discovered, would have become an indispensable part of daily life. Understanding and use of twisted fibres implies the use of complex multi-component technology as well as a mathematical understanding of pairs, sets, and numbers. Added to recent evidence of birch bark tar, art, and shell beads, the idea that Neanderthals were cognitively inferior to modern humans is becoming increasingly untenable.

Pectic galactan affects cell wall architecture during secondary cell wall deposition.

MAIN CONCLUSION: ß-(1,4)-galactan determines the interactions between different matrix polysaccharides and cellulose during the cessation of cell elongation. Despite recent advances regarding the role of pectic ß-(1,4)-galactan neutral side chains in primary cell wall remodelling during growth and cell elongation, little is known about the specific function of this polymer in other developmental processes. We have used transgenic Arabidopsis plants overproducing chickpea ßI-Gal ß-galactosidase under the 35S CaMV promoter (35S::ßI-Gal) with reduced galactan levels in the basal non-elongating floral stem internodes to gain insight into the role of ß-(1,4)-galactan in cell wall architecture during the cessation of elongation and the beginning of secondary growth. The loss of galactan mediated by ßI-Gal in 35S::ßI-Gal plants is accompanied by a reduction in the levels of KOH-extracted xyloglucan and an increase in the levels of xyloglucan released by a cellulose-specific endoglucanase. These variations in cellulose-xyloglucan interactions cause an altered xylan and mannan deposition in the cell wall that in turn results in a deficient lignin deposition. Considering these results, we can state that ß-(1,4)-galactan plays a key structural role in the correct organization of the different domains of the cell wall during the cessation of growth and the early events of secondary cell wall development. These findings reinforce the notion that there is a mutual dependence between the different polysaccharides and lignin polymers to form an organized and functional cell wall.

Cellulose, pectin and water in cell walls determine apple flesh viscoelastic mechanical properties.

The viscoelastic mechanical properties are important quality traits for fleshy fruit uses. The contribution of cell wall polysaccharides chemistry and organization on their variability was studied in six varieties of apple. Correlation between damping and storage modulus of plasmolyzed tissue distinguished better apple varieties on their viscoelasticity than fresh samples. Galactose, arabinose and uronic acids correlated positively with the storage modulus of fresh apple samples (E'f). These corresponded to 4-linked galactan but no specific arabinose linkage. Galacturonic acid branched on O-3 and terminal rhamnose correlated negatively with E'f. These correlations formed two groups of fruit except for branched methyl-esterified galacturonic. Solid-state 13C NMR spectroscopy analyses showed that E'f correlated negatively with cellulose C4 T1ρH relaxation and positively with pectin methyl esters THH proton diffusion. The results point to the key roles of pectin structure and hydration and cellulose microfibrils distribution on apple mechanical properties.

A predictive spatial model for roasted coffee using oxygen isotopes of α-cellulose.

RATIONALE: Fraudulent region-of-origin labeling is a concern for high-value, globally traded commodities such as coffee. The oxygen isotope ratio of cellulose is a useful geographic tracer, as it integrates climate and source water signals. A predictive spatial model ("isoscape") of the δ18 O values of coffee bean cellulose is generated to evaluate coffee region-of-origin claims. METHODS: The oxygen isotope ratio of α-cellulose extracted from roasted coffee beans was measured via high-temperature conversion elemental analyzer/isotope ratio mass spectrometry (TC-EA/IRMS) and used to calculate the δ18 O value of coffee bean water. The 18 O enrichment of coffee bean water relative to the δ18 O value of local precipitation was modeled as a function of local temperature and humidity. This function was incorporated into a mechanistic model of cellulose δ18 O values to predict the δ18 O values of coffee bean cellulose across coffee-producing regions globally. RESULTS: The δ18 O values of analyzed coffee bean cellulose ranged from approximately +22‰ to +42‰ (V-SMOW). As expected, coffees grown in the same region tended to have similar isotope ratios, and the δ18 O value of coffee bean cellulose was generally higher than the δ18 O value of modeled stem cellulose for the region. Modeled δ18 O values of coffee cellulose were within ±2.3‰ of the measured δ18 O value of coffee cellulose. CONCLUSIONS: The oxygen isotope ratio of coffee bean cellulose is a useful indicator of region-of-origin and varies predictably in response to climatic factors and precipitation isotope ratios. The isoscape of coffee bean cellulose δ18 O values from this study provides a quantitative tool that can be applied to region-of-origin verification of roasted coffee at the point-of-sale.

Sequencing of Chinese castor lines reveals genetic signatures of selection and yield-associated loci.

Oil produced by castor (Ricinus communis) has broad industrial applications. However, knowledge on the genetic diversity, especially genetic alterations that occurred during domestication and subsequent traits selection, of this oil crop is limited. Here, our population genomics analyses show that the Chinese castors have developed a geographic pattern, classified into the southern-, the middle-, and the northern-China groups. We detect a number of candidate genomic loci that are associated with the selection signals during the geographical differentiation and domestication. Using genome-wide association analysis, we identify candidate genes associated with nine agronomically important traits. One of the candidate genes encoding a glycosyltransferase related to cellulose and lignin biosynthesis is associated with both capsule dehiscence and endocarp thickness. We hypothesize that the abundance of cellulose or lignin in endocarp is an important factor for capsule dehiscence. Our results provide foundation for castor breeding and genetic study.