Papers by Marilyn Henderson
Bioresource Technology, 2015
Global grape production could generate up to 13 Mt/yr of wasted biomass. The compositions of Cabe... more Global grape production could generate up to 13 Mt/yr of wasted biomass. The compositions of Cabernet Sauvignon (red marc) and Sauvignon Blanc (white marc) were analyzed with a view to using marc as raw material for biofuel production. On a dry weight basis, 31−54% w/w of the grape marc consisted of carbohydrate, of which 47−80% was soluble in aqueous media. Ethanol insoluble residues consisted mainly of polyphenols, pectic polysaccharides, heteroxylans and cellulose. Acid and thermal pretreatments were investigated for their effects on subsequent cellulose saccharification. A 0.5 M sulfuric acid pre-treatment yielded a 10% increase in the amount of liberated glucose after enzymatic saccharification. The theoretical amount of bioethanol that could be produced by fermentation of grape marc was up to 400 L/t. However, bioethanol from only soluble carbohydrates could yield 270 L/t, leaving a polyphenol enriched fraction that may be used in animal feed or as fertilizer.
Journal of Cereal Science, 2015
Sorghum is a staple food for half a billion people and, through growth on marginal land with mini... more Sorghum is a staple food for half a billion people and, through growth on marginal land with minimal inputs, is an important source of feed, forage and increasingly, biofuel feedstock. Here we present information about non-cellulosic cell wall polysaccharides in a diverse set of cultivated and wild Sorghum bicolor grains. Sorghum grain contains predominantly starch (64e76%) but is relatively deficient in other polysaccharides present in wheat, oats and barley. Despite overall low quantities, sorghum germplasm exhibited a remarkable range in polysaccharide amount and structure. Total (1,3;1,4)-b-glucan ranged from 0.06 to 0.43% (w/w) whilst internal cellotriose:cellotetraose ratios ranged from 1.8 to 2.9:1. Arabinoxylan amounts fell between 1.5 and 3.6% (w/w) and the arabinose:xylose ratio, denoting arabinoxylan structure, ranged from 0.95 to 1.35. The distribution of these and other cell wall polysaccharides varied across grain tissues as assessed by electron microscopy. When ten genotypes were tested across five environmental sites, genotype (G) was the dominant source of variation for both (1,3;1,4)-b-glucan and arabinoxylan content (69e74%), with environment (E) responsible for 5e14%. There was a small G Â E effect for both polysaccharides. This study defines the amount and spatial distribution of polysaccharides and reveals a significant genetic influence on cell wall composition in sorghum grain.
New Phytologist, 2014
Summary In plants, cell walls are one of the first lines of defence for protecting cells from suc... more Summary In plants, cell walls are one of the first lines of defence for protecting cells from successful invasion by fungal pathogens and are a major factor in basal host resistance. For the plant cell to block penetration attempts, it must adapt its cell wall to withstand the physical and chemical forces applied by the fungus. Papillae that have been effective in preventing penetration by pathogens are traditionally believed to contain callose as the main polysaccharide component. Here, we have re‐examined the composition of papillae of barley (Hordeum vulgare) attacked by the powdery mildew fungus Blumeria graminis f. sp. hordei (Bgh) using a range of antibodies and carbohydrate‐binding modules that are targeted to cell wall polysaccharides. The data show that barley papillae induced during infection with Bgh contain, in addition to callose, significant concentrations of cellulose and arabinoxylan. Higher concentrations of callose, arabinoxylan and cellulose are found in effective...
Plant Biotechnology Journal, 2011
SummaryCell walls in commercially important cereals and grasses are characterized by the presence... more SummaryCell walls in commercially important cereals and grasses are characterized by the presence of (1,3;1,4)‐β‐d‐glucans. These polysaccharides are beneficial constituents of human diets, where they can reduce the risk of hypercholesterolemia, type II diabetes, obesity and colorectal cancer. The biosynthesis of cell wall (1,3;1,4)‐β‐d‐glucans in the Poaceae is mediated, in part at least, by the cellulose synthase‐like CslF family of genes. Over‐expression of the barley CslF6 gene under the control of an endosperm‐specific oat globulin promoter results in increases of more than 80% in (1,3;1,4)‐β‐d‐glucan content in grain of transgenic barley. Analyses of (1,3;1,4)‐β‐d‐glucan fine structure indicate that individual CslF enzymes might direct the synthesis of (1,3;1,4)‐β‐d‐glucans with different structures. When expression of the CslF6 transgene is driven by the Pro35S promoter, the transgenic lines have up to sixfold higher levels of (1,3;1,4)‐β‐d‐glucan in leaves, but similar level...
Plant physiology, 2018
Cell walls are crucial for the integrity and function of all land plants and are of central impor... more Cell walls are crucial for the integrity and function of all land plants and are of central importance in human health, livestock production, and as a source of renewable bioenergy. Many enzymes that mediate the biosynthesis of cell wall polysaccharides are encoded by members of the large () gene superfamily. Here, we analyzed 29 sequenced genomes and 17 transcriptomes to revise the phylogeny of the gene superfamily in angiosperms. Our results identify ancestral gene clusters that predate the monocot-eudicot divergence and reveal several novel evolutionary observations, including the expansion of the Poaceae-specific cellulose synthase-like family to the graminids and restiids and the characterization of a previously unreported eudicot lineage, , that forms a reciprocally monophyletic eudicot-monocot grouping with the clade. The lineage is widely distributed in eudicots, and the clade, which was thought previously to be restricted to the Poales, is widely distributed in monocots. Ou...
Cellulose synthase (CesA) and Cellulose synthase-like (Csl) gene families in S. italica. Table S2... more Cellulose synthase (CesA) and Cellulose synthase-like (Csl) gene families in S. italica. Table S2. Primer sequences for the amplification of transcripts of control genes and Cellulose synthase-like genes (Csl) F, H and J in S. viridis. (DOCX 19 kb)
BMC Plant Biology, 2015
Background: Setaria viridis has emerged as a model species for the larger C 4 grasses. Here the c... more Background: Setaria viridis has emerged as a model species for the larger C 4 grasses. Here the cellulose synthase (CesA) superfamily has been defined, with an emphasis on the amounts and distribution of (1,3;1,4)-β-glucan, a cell wall polysaccharide that is characteristic of the grasses and is of considerable value for human health. Methods: Orthologous relationship of the CesA and Poales-specific cellulose synthase-like (Csl) genes among Setaria italica (Si), Sorghum bicolor (Sb), Oryza sativa (Os), Brachypodium distachyon (Bradi) and Hordeum vulgare (Hv) were compared using bioinformatics analysis. Transcription profiling of Csl gene families, which are involved in (1,3;1,4)-β-glucan synthesis, was performed using real-time quantitative PCR (Q-PCR). The amount of (1,3;1,4)-β-glucan was measured using a modified Megazyme assay. The fine structures of the (1,3;1,4)-β-glucan, as denoted by the ratio of cellotriosyl to cellotetraosyl residues (DP3:DP4 ratio) was assessed by chromatography (HPLC and HPAEC-PAD). The distribution and deposition of the MLG was examined using the specific antibody BG-1 and captured using fluorescence and transmission electron microscopy (TEM). Results: The cellulose synthase gene superfamily contains 13 CesA and 35 Csl genes in Setaria. Transcript profiling of CslF, CslH and CslJ gene families across a vegetative tissue series indicated that SvCslF6 transcripts were the most abundant relative to all other Csl transcripts. The amounts of (1,3;1,4)-β-glucan in Setaria vegetative tissues ranged from 0.2% to 2.9% w/w with much smaller amounts in developing grain (0.003% to 0.013% w/w). In general, the amount of (1,3;1,4)-β-glucan was greater in younger than in older tissues. The DP3:DP4 ratios varied between tissue types and across developmental stages, and ranged from 2.4 to 3.0:1. The DP3:DP4 ratios in developing grain ranged from 2.5 to 2.8:1. Micrographs revealing the distribution of (1,3;1,4)-β-glucan in walls of different cell types and the data were consistent with the quantitative (1,3;1,4)-β-glucan assays. Conclusion: The characteristics of the cellulose synthase gene superfamily and the accumulation and distribution of (1,3;1,4)-β-glucans in Setaria are similar to those in other C 4 grasses, including sorghum. This suggests that Setaria is a suitable model plant for cell wall polysaccharide biology in C 4 grasses.
PloS one, 2015
Plant biomass from different species is heterogeneous, and this diversity in composition can be m... more Plant biomass from different species is heterogeneous, and this diversity in composition can be mined to identify materials of value to fuel and chemical industries. Agave produces high yields of energy-rich biomass, and the sugar-rich stem tissue has traditionally been used to make alcoholic beverages. Here, the compositions of Agave americana and Agave tequilana leaves are determined, particularly in the context of bioethanol production. Agave leaf cell wall polysaccharide content was characterized by linkage analysis, non-cellulosic polysaccharides such as pectins were observed by immuno-microscopy, and leaf juice composition was determined by liquid chromatography. Agave leaves are fruit-like-rich in moisture, soluble sugars and pectin. The dry leaf fiber was composed of crystalline cellulose (47-50% w/w) and non-cellulosic polysaccharides (16-22% w/w), and whole leaves were low in lignin (9-13% w/w). Of the dry mass of whole Agave leaves, 85-95% consisted of soluble sugars, cel...
The New phytologist, Jan 3, 2015
Heterodera avenae (cereal cyst nematode, CCN) infects the roots of barley (Hordeum vulgare) formi... more Heterodera avenae (cereal cyst nematode, CCN) infects the roots of barley (Hordeum vulgare) forming syncytial feeding sites. In resistant host plants, relatively few females develop to maturity. Little is known about the physiological and biochemical changes induced during CCN infection. Responses to CCN infection were investigated in resistant (Rha2) and susceptible barley cultivars through histological, compositional and transcriptional analysis. Two phases were identified that influence CCN viability, including feeding site establishment and subsequent cyst maturation. Syncytial development progressed faster in the resistant cultivar Chebec than in the susceptible cultivar Skiff, and was accompanied by changes in cell wall polysaccharide abundance, particularly (1,3;1,4)-β-glucan. Transcriptional profiling identified several glycosyl transferase genes, including CELLULOSE SYNTHASE-LIKE F10 (HvCslF10), which may contribute to differences in polysaccharide abundance between resista...
BMC Plant Biology, 2015
Background: The ability to increase cellulose content and improve the stem strength of cereals co... more Background: The ability to increase cellulose content and improve the stem strength of cereals could have beneficial applications in stem lodging and producing crops with higher cellulose content for biofuel feedstocks. Here, such potential is explored in the commercially important crop barley through the manipulation of cellulose synthase genes (CesA). Results: Barley plants transformed with primary cell wall (PCW) and secondary cell wall (SCW) barley cellulose synthase (HvCesA) cDNAs driven by the CaMV 35S promoter, were analysed for growth and morphology, transcript levels, cellulose content, stem strength, tissue morphology and crystalline cellulose distribution. Transcript levels of the PCW HvCesA transgenes were much lower than expected and silencing of both the endogenous CesA genes and introduced transgenes was often observed. These plants showed no aberrant phenotypes. Although attempts to over-express the SCW HvCesA genes also resulted in silencing of the transgenes and endogenous SCW HvCesA genes, aberrant phenotypes were sometimes observed. These included brittle nodes and, with the 35S:HvCesA4 construct, a more severe dwarfing phenotype, where xylem cells were irregular in shape and partially collapsed. Reductions in cellulose content were also observed in the dwarf plants and transmission electron microscopy showed a significant decrease in cell wall thickness. However, there were no increases in overall crystalline cellulose content or stem strength in the CesA over-expression transgenic plants, despite the use of a powerful constitutive promoter. Conclusions: The results indicate that the cellulose biosynthetic pathway is tightly regulated, that individual CesA proteins may play different roles in the synthase complex, and that the sensitivity to CesA gene manipulation observed here suggests that in planta engineering of cellulose levels is likely to require more sophisticated strategies.
Journal of Experimental Botany, 2013
To explain the low levels of starch, high levels of (1,3;1,4)-β-glucan, and thick cell walls in g... more To explain the low levels of starch, high levels of (1,3;1,4)-β-glucan, and thick cell walls in grains of Brachypodium distachyon L. relative to those in other Pooideae, aspects of grain development were compared between B. distachyon and barley (Hordeum vulgare L.). Cell proliferation, cell expansion, and endoreduplication were reduced in B. distachyon relative to barley and, consistent with these changes, transcriptional downregulation of the cell-cycle genes CDKB1 and cyclin A3 was observed. Similarly, reduced transcription of starch synthase I and starch-branching enzyme I was observed as well as reduced activity of starch synthase and ADP-glucose pyrophosphorylase, which are consistent with the lowered starch content in B. distachyon grains. No change was detected in transcription of the major gene involved in (1,3;1,4)-β-glucan synthesis, cellulose synthase-like F6. These results suggest that, while low starch content results from a reduced capacity for starch synthesis, the unusually thick cell walls in B. distachyon endosperm probably result from continuing (1,3;1,4)-β-glucan deposition in endosperm cells that fail to expand. This raises the possibility that endosperm expansion is linked to starch deposition.
Journal of Integrative Plant Biology, 2015
In cereals, the presence of soluble polysaccharides including (1,3;1,4)‐β‐glucan has downstream i... more In cereals, the presence of soluble polysaccharides including (1,3;1,4)‐β‐glucan has downstream implications for human health, animal feed and biofuel applications. Sorghum bicolor (L.) Moench is a versatile crop, but there are limited reports regarding the content of such soluble polysaccharides. Here, the amount of (1,3;1,4)‐β‐glucan present in sorghum tissues was measured using a Megazyme assay. Very low amounts were present in the grain, ranging from 0.16%–0.27% (w/w), while there was a greater quantity in vegetative tissues at 0.12–1.71% (w/w). The fine structure of (1,3;1,4)‐β‐glucan, as denoted by the ratio of cellotriosyl and cellotetraosyl residues, was assessed by high performance liquid chromatography (HPLC) and ranged from 2.6–3:1 in the grain, while ratios in vegetative tissues were lower at 2.1–2.6:1. The distribution of (1,3;1,4)‐β‐glucan was examined using a specific antibody and observed with fluorescence and transmission electron microscopy. Micrographs showed a va...
Bayesian phylogenetic tree of the CesA, CslD, CslE, CslF, CslH and CslJ genes in Setaria italica,... more Bayesian phylogenetic tree of the CesA, CslD, CslE, CslF, CslH and CslJ genes in Setaria italica, Sorghum bicolor, Oriza sativa, Brachypodium distachyon and Hordeum vulgare. Figure S2. Transcript levels of (1,3;1,4)-β-glucan synthase genes from S. viridis. Figure S3. Comparison of the transcripts levels of SvCslH genes from S. viridis. Figure S4. Correlation of the Cellulose synthase-like transcript levels. Figure S5. Normalised transcript levels of SvCslJ from S. viridis. Figure S6. TEM micrographs of leaf immunogold labelled with BG-1. Figure S7. TEM micrographs of stem sections immunogold labelled with BG-1 Figure S8. TEM micrographs of root sections immunogold labelled with BG-1. Figure S9. Micrographs of developing grain transverse sections. Figure S10. TEM micrographs of grain immunogold labelled with BG-1. Figure S11. Phenotype of Setaria viridis in different growth stages. Figure S12. Control micrographs of TEM of H. vulgare leaf sections. (PPTX 17100 kb)
Uploads
Papers by Marilyn Henderson