The in vivo impact of MsLAC1, a Miscanthus laccase isoform, on lignification and lignin composition contrasts with its in vitro substrate preference
The in vivo impact of MsLAC1, a Miscanthus laccase isoform, on lignification and lignin composition contrasts with its in vitro substrate preference
复制标题
DOI：
10.1186/s12870-019-2174-3
复制
发表时间：
2019-12-12
影响因子：
5.3
通讯作者：
Wolf, Sebastian
中科院分区：
文献类型：
--
作者：
He, Feng;Machemer-Noonan, Katja;Wolf, Sebastian
背景了解木质素生物合成和组成对于可持续生物能源和生物材料生产至关重要。芒属物种由于其快速生长和适度的营养需求而成为有前途的生物能源作物。然而，人们对芒草中的木质素聚合知之甚少。此前研究表明，植物漆酶是在植物中具有多种功能的酚氧化酶，其中之一是木质素单体的聚合。在此，我们将新发现的芒草漆酶 MsLAC1 与细胞壁木质化联系起来。对重组 MsLAC1 和表达 MsLAC1 的拟南芥转基因植物进行表征，以了解 MsLAC1 的体外和体内功能。结果通过全面的分子、生化和组织化学分析，我们发现 MsLAC1 定位于细胞壁，并鉴定出能够调节 MsLAC1 表达的芒草转录因子。此外，MsLAC1 补充了拟南芥 lac4-2 lac17 突变体，重组的 MsLAC1 能够在体外氧化木质醇单体。过表达 MsLAC1 的转基因拟南芥植物显示出更高的 G-木质素含量，尽管重组 MsLAC1 似乎更喜欢芥子醇作为底物。结论 总之，我们的结果表明 MsLAC1 受次生细胞壁 MYB 转录因子调节，并参与木质部纤维的木质化。该报告将 MsLAC1 确定为芒草中用于生物燃料和生物材料应用的有前景的育种目标。
Background Understanding lignin biosynthesis and composition is of central importance for sustainable bioenergy and biomaterials production. Species of the genus Miscanthus have emerged as promising bioenergy crop due to their rapid growth and modest nutrient requirements. However, lignin polymerization in Miscanthus is poorly understood. It was previously shown that plant laccases are phenol oxidases that have multiple functions in plant, one of which is the polymerization of monolignols. Herein, we link a newly discovered Miscanthus laccase, MsLAC1, to cell wall lignification. Characterization of recombinant MsLAC1 and Arabidopsis transgenic plants expressing MsLAC1 were carried out to understand the function of MsLAC1 both in vitro and in vivo. Results Using a comprehensive suite of molecular, biochemical and histochemical analyses, we show that MsLAC1 localizes to cell walls and identify Miscanthus transcription factors capable of regulating MsLAC1 expression. In addition, MsLAC1 complements the Arabidopsis lac4-2 lac17 mutant and recombinant MsLAC1 is able to oxidize monolignol in vitro. Transgenic Arabidopsis plants over-expressing MsLAC1 show higher G-lignin content, although recombinant MsLAC1 seemed to prefer sinapyl alcohol as substrate. Conclusions In summary, our results suggest that MsLAC1 is regulated by secondary cell wall MYB transcription factors and is involved in lignification of xylem fibers. This report identifies MsLAC1 as a promising breeding target in Miscanthus for biofuel and biomaterial applications.