초록
<P><B>Abstract</B></P> <P>Ethanol production from lignocellulosic biomass has been considered an alternative to corn-based ethanol and fossil fuel. However, the secondary cell wall structure prevents efficient degradation of cellulose. Expression of cell wall degrading enzymes has been suggested as one solution to generate suitable feedstocks for lignocellulosic ethanol production. Swollenin (SWO), originating from <I>Trichoderma reesei</I>, disrupts cellulose structure with low-level hydrolytic activity to the glucan chain. Previously, characterization of <I>T. reesei</I> SWO has been carried out in multiple microorganisms and tobacco. This study heterologously overexpressed <I>T. reesei SWO</I> in hybrid poplar (<I>Populus tremula</I> × <I>alba</I>), a promising feedstock for biofuel production, under the control of either the constitutive Cauliflower Mosaic Virus 35S (CaMV 35S) promoter or the putative vascular tissue specific Subterranean Clover Stunt Virus S7 (SCSV) promoter. Transgenic poplar lines with high or moderate <I>SWO</I> expression level showed abnormal growth and reduced biomass production, along with increased glucose and reduced lignin contents. Increased cellulose crystallinity was observed in two transgenic events. This study also investigated the effect of <I>in planta</I> SWO expression on cellulose saccharification efficiency and found that transgenic events improved glucan conversion rates compared to wild type poplar. The results suggest <I>SWO</I>-overexpressing transgenic poplar lines could be a potential feedstock for ethanol production.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Transgenic <I>SWO</I>-overexpressing poplar produced bioactive SWO protein. </LI> <LI> <I>In planta</I> expression of <I>SWO</I> impacted plant growth and cell wall composition. </LI> <LI> <I>SWO</I>-overexpressing poplar had enhanced glucan saccharification efficiency. </LI> </UL> </P>