Zhao Shuai, Wei Hui, Lin Chien-Yuan, Zeng Yining, Tucker Melvin P, Himmel Michael E, Ding Shi-You
Bioscience Center, National Renewable Energy Laboratory Golden, CO, USA.
National Bioenergy Center, National Renewable Energy Laboratory Golden, CO, USA.
Front Plant Sci. 2016 Jan 29;7:24. doi: 10.3389/fpls.2016.00024. eCollection 2016.
It is known that plant growth promoting bacteria (PGPB) elicit positive effects on plant growth and biomass yield. However, the actual mechanism behind the plant-PGPB interaction is poorly understood, and the literature is scarce regarding the thermochemical pretreatability and enzymatic degradability of biomass derived from PGPB-inoculated plants. Most recent transcriptional analyses of PGPB strain Burkholderia phytofirmans PsJN inoculating potato in literature and Arabidopsis in our present study have revealed the expression of genes for ferritin and the biosynthesis and transport of siderophores (i.e., the molecules with high affinity for iron), respectively. The expression of such genes in the shoots of PsJN-inoculated plants prompted us to propose that PsJN-inoculation can improve the host plant's iron uptake and accumulation, which facilitates the downstream plant biomass pretreatment and conversion to simple sugars. In this study, we employed B. phytofirmans PsJN to inoculate the Arabidopsis thaliana plants, and conducted the first investigation for its effects on the biomass yield, the anatomical organization of stems, the iron accumulation, and the pretreatment and enzymatic hydrolysis of harvested biomass. The results showed that the strain PsJN stimulated plant growth in the earlier period of plant development and enlarged the cell size of stem piths, and it also indeed enhanced the essential metals uptake and accumulation in host plants. Moreover, we found that the PsJN-inoculated plant biomass released more glucose and xylose after hot water pretreatment and subsequent co-saccharification, which provided a novel insight into development of lignocellulosic biofuels from renewable biomass resources.
已知植物促生细菌（PGPB）对植物生长和生物量产量具有积极影响。然而，植物与PGPB相互作用背后的实际机制尚不清楚，关于源自接种PGPB植物的生物质的热化学预处理和酶降解性的文献也很匮乏。最近关于PGPB菌株伯克霍尔德氏菌植物坚芽孢杆菌PsJN接种马铃薯的转录分析以及我们目前对拟南芥的研究表明，分别有铁蛋白基因以及铁载体（即对铁具有高亲和力的分子）的生物合成和转运相关基因的表达。这些基因在接种PsJN植物的地上部分的表达促使我们提出，接种PsJN可以提高宿主植物对铁的吸收和积累，这有利于下游植物生物质的预处理以及转化为单糖。在本研究中，我们利用植物坚芽孢杆菌PsJN接种拟南芥植物，并首次研究了其对生物量产量、茎的解剖结构、铁积累以及收获生物质的预处理和酶水解的影响。结果表明，PsJN菌株在植物发育早期促进了植物生长，扩大了茎髓的细胞大小，并且确实增强了宿主植物对必需金属的吸收和积累。此外，我们发现接种PsJN的植物生物质在热水预处理和随后的共糖化后释放出更多的葡萄糖和木糖，这为从可再生生物质资源开发木质纤维素生物燃料提供了新的见解。
