title: Functional co-expression of a fungal ferulic acid esterase and a β-1,4 endoxylanase in Festuca arundinacea (tall fescue) modifies post-harvest cell wall deconstruction.
abstract: Improved post-harvest cell wall deconstruction of tall fescue leaves has been demonstrated by in-planta co-expression of a constitutively expressed ferulic acid esterase together with a senescence-induced β-1,4 endoxylanase. Tall fescue plants (Festuca arundinacea) constitutively expressing vacuole- or apoplast-targeted ferulic acid esterase from Aspergillus niger were retransformed with a senescence-induced and apoplast-targeted β-1,4 endo-xylanase from Trichoderma reesei. Enzyme activities in co-expressing plants stabilized after repeated vegetative propagation, with xylanase activity in senescent leaves increasing and ferulic acid esterase activity decreasing after tillering. Plants co-expressing both enzymes in the apoplast, with the lowest levels of ferulate monomers and dimers and the lowest levels of cell wall arabinoxylans, released ten times more cell wall hydroxycinnamic acids and five times more arabinoxylan from the cell wall on autodigestion compared to expression of ferulic acid esterase or xylanase alone. These plants also showed a 31 % increase in cellulase-mediated release of reducing sugars, a 5 % point increase in in vitro dry matter digestibility and a 23 % increase in acetyl bromide-soluble lignin. However, plant growth was adversely affected by expressing FAE in the apoplast, giving plants with narrower shorted leaves, and a 71 % decrease in biomass.
authors: Department of Biology, The Pennsylvania State University, 208 Mueller Laboratory, University Park, PA, 16802, USA, mmb26@psu.edu.
authors: Marcia M de O
authors: MM
authors: Buanafina
authors: Sue
authors: S
authors: Dalton
authors: Tim
authors: T
authors: Langdon
authors: E
authors: E
authors: Timms-Taravella
authors: Erica A
authors: EA
authors: Shearer
authors: Phillip
authors: P
authors: Morris
mesh_terms: D001234:Aspergillus niger / Q000201:enzymology*; D002265:Carboxylic Ester Hydrolases / Q000378:metabolism*; D002473:Cell Wall / Q000378:metabolism*; D003373:Coumaric Acids / Q000378:metabolism; D043364:Endo-1,4-beta Xylanases / Q000378:metabolism*; D031751:Festuca / Q000166:cytology* / Q000235:genetics / Q000254:growth & development*; D063245:Plant Development; D010936:Plant Extracts / Q000378:metabolism; D018515:Plant Leaves / Q000378:metabolism; D030821:Plants, Genetically Modified; D014170:Transformation, Genetic; D014242:Trichoderma / Q000201:enzymology*
chemical_list: D003373:Coumaric Acids; D010936:Plant Extracts; D002265:Carboxylic Ester Hydrolases; C070196:feruloyl esterase; D043364:Endo-1,4-beta Xylanases