State Key Laboratory of Tree Genetics and Breeding, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, 100083, China.
Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China.
Nat Commun. 2023 Jul 18;14(1):4285. doi: 10.1038/s41467-023-39930-3.
The conversion of lignocellulosic feedstocks to fermentable sugar for biofuel production is inefficient, and most strategies to enhance efficiency directly target lignin biosynthesis, with associated negative growth impacts. Here we demonstrate, for both laboratory- and field-grown plants, that expression of Pag-miR408 in poplar (Populus alba × P. glandulosa) significantly enhances saccharification, with no requirement for acid-pretreatment, while promoting plant growth. The overexpression plants show increased accessibility of cell walls to cellulase and scaffoldin cellulose-binding modules. Conversely, Pag-miR408 loss-of-function poplar shows decreased cell wall accessibility. Overexpression of Pag-miR408 targets three Pag-LACCASES, delays lignification, and modestly reduces lignin content, S/G ratio and degree of lignin polymerization. Meanwhile, the LACCASE loss of function mutants exhibit significantly increased growth and cell wall accessibility in xylem. Our study shows how Pag-miR408 regulates lignification and secondary growth, and suggest an effective approach towards enhancing biomass yield and saccharification efficiency in a major bioenergy crop.
将木质纤维素原料转化为可发酵糖用于生物燃料生产的效率较低，大多数提高效率的策略都直接针对木质素生物合成，这会带来生长的负面影响。在这里，我们展示了在实验室和田间生长的植物中，杨树（Populus alba × P. glandulosa）中 Pag-miR408 的表达显著提高了糖化效率，而不需要酸预处理，同时促进了植物生长。过表达植株表现出细胞壁对纤维素酶和支架纤维素结合模块的可及性增加。相反，Pag-miR408 功能丧失型杨树表现出细胞壁可及性降低。Pag-miR408 的过表达靶向三个 Pag-LACCASE，延迟木质化，并适度降低木质素含量、S/G 比和木质素聚合度。与此同时，LACCASE 功能丧失突变体在木质部中表现出显著增加的生长和细胞壁可及性。我们的研究表明 Pag-miR408 如何调节木质化和次生生长，并为提高主要生物能源作物的生物量产量和糖化效率提供了一种有效方法。
