Transcriptional changes related to secondary wall formation in xylem of transgenic lines of tobacco altered for lignin or xylan content which show improved saccharification

Cook, Charis; Daudi, Arsalan; Millar, David J.; Bindschedler, Laurence V.; Khan, Safina; Bolwell, G. Paul; Devoto, Alessandra

doi:10.1016/j.phytochem.2011.10.009

Cited by 17 publications

(24 citation statements)

References 62 publications

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“…Although more sugar was released from all pretreated genotypes, prx was the line with the highest release of sugar per milligram of AIM both in the absence and presence of the fungus. This is consistent with previously published data [39]. Conversely, the increase in sugar released from uxs as compared to the WT K326 after fungal pretreatment was not striking.…”

Section: Selection Of Pretreatment Methodssupporting

confidence: 93%

“…Initial pretreatment trials were carried out on tobacco WT plants belonging to the K326 cultivar [39,41] according to a method adapted from Keller and colleagues [42]. Acetoneinsoluble cell wall material (AIM) pretreated with this technique did not result in improved sugar release after enzymatic saccharificat ion (data not shown).…”

Section: Selection Of Pretreatment Methodsmentioning

confidence: 99%

“…We also included in the experiment line uxs, which was obtained in the K326 background [46]. Improved saccharification of uxs and prx material in the absence of pretreatments is already described [39].…”

Section: Selection Of Pretreatment Methodsmentioning

confidence: 99%

“…We previously showed that in the tobacco (Nicotiana tabacum) prx line, in which the TOBACCO PEROXIDASE 60 gene is down-regulated and polymerisation of lignin monomers is prevented, lignin content is reduced by 25 % [38]. This line showed a 30 % improvement in sugar released per milligram of cell wall material compared to the wild type (WT) [39]. A xylan down-regulated tobacco line (uxs) also showed a significant improvement in saccharification efficiency [39].…”

Section: Modification Of Plant Cell Walls For Improvement Of Cellulosmentioning

confidence: 99%

“…This line showed a 30 % improvement in sugar released per milligram of cell wall material compared to the wild type (WT) [39]. A xylan down-regulated tobacco line (uxs) also showed a significant improvement in saccharification efficiency [39]. An independent study showed that the expression of a fungal polygalacturonase (PG) in Arabidopsis thaliana caused a decrease in levels of de-esterified HG, with a consequent improvement of saccharification efficiency [35].…”

Section: Modification Of Plant Cell Walls For Improvement Of Cellulosmentioning

confidence: 99%

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Combination of Pretreatment with White Rot Fungi and Modification of Primary and Secondary Cell Walls Improves Saccharification

et al. 2014

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Plant cell walls have protective and structural functions conferring resistance to degradation. The lignin and hemicellulose network surrounding the cellulose microfibrils is insoluble unless subjected to harsh treatments. As lignin, pectin and xylan are effective barriers to cellulose extraction and hydrolysis, reducing their presence in cell walls improves saccharification. Microorganisms that can depolymerise lignin are of extreme interest to the biofuel industry. White rot fungi can be effective in pretreatment of lignocellulosic biomass prior to saccharification. Here, we show the cumulative effects of pretreating biomass with two white rot fungi, Phanerochaete chrysosporium and Trametes cingulata, on tobacco lines with reduced lignin or xylan, caused by suppression of the CINNAMOYL-CoA REDUCTASE, CINNAMATE-4-HYDROXYLASE, TOBACCO PEROXI-DASE 60 or UDP-GLUCURONATE DECARBOXYLASE and on Arabidopsis thaliana with reduced de-esterified homogalacturonan content, obtained by overexpressing a pectin methyl esterase inhibitor or constitutively expressing the Aspergillus nigerPOLYGALACTURONASE II gene. Tests were extended to fresh material from an Arabidopsis mutant for a cell wall peroxidase. We demonstrate that fungal pretreatment is a reliable method of improving cellulose accessibility in biofuel feedstocks, fresh material and cell wall residues from different plants. These results contribute to the understanding of the consequences of primary and secondary cell wall perturbations on lignocellulosic biomass accessibility to white rot fungi and on saccharification yield. A comparison of the effects of P. chrysosporium and T. cingulata on tobacco saccharification also highlights the limitation of current knowledge in this research field and the necessity to systematically test culture conditions to avoid generalisations.

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Section: Selection Of Pretreatment Methodssupporting

confidence: 93%