Ishizawa Hidehiro, Kuroda Masashi, Morikawa Masaaki, Ike Michihiko
Division of Sustainable Energy and Environmental Engineering, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871 Japan.
Division of Biosphere Science, Graduate School of Environmental Science, Hokkaido University, N10-W5, Kita-ku, Sapporo, 060-0810 Japan.
Biotechnol Biofuels. 2017 Mar 10;10:62. doi: 10.1186/s13068-017-0746-8. eCollection 2017.
Duckweed (family ) has recently been recognized as an ideal biomass feedstock for biofuel production due to its rapid growth and high starch content, which inspired interest in improving their productivity. Since microbes that co-exist with plants are known to have significant effects on their growth according to the previous studies for terrestrial plants, this study has attempted to understand the plant-microbial interactions of a duckweed, , focusing on the growth promotion/inhibition effects so as to assess the possibility of accelerated duckweed production by modifying co-existing bacterial community.
Co-cultivation of aseptic and bacterial communities collected from various aquatic environments resulted in changes in duckweed growth ranging from -24 to +14% compared to aseptic control. A number of bacterial strains were isolated from both growth-promoting and growth-inhibitory communities, and examined for their co-existing effects on duckweed growth. Irrespective of the source, each strain showed promotive, inhibitory, or neutral effects when individually co-cultured with . To further analyze the interactions among these bacterial strains in a community, binary combinations of promotive and inhibitory strains were co-cultured with aseptic , resulting in that combinations of promotive-promotive or inhibitory-inhibitory strains generally showed effects similar to those of individual strains. However, combinations of promotive-inhibitory strains tended to show inhibitory effects while only H3 exerted its plant growth-promoting effect in all combinations tested.
Significant change in biomass production was observed when duckweed was co-cultivated with environmental bacterial communities. Promotive, neutral, and inhibitory bacteria in the community would synergistically determine the effects. The results indicate the possibility of improving duckweed biomass production via regulation of co-existing bacterial communities.
浮萍（浮萍科）由于其生长迅速且淀粉含量高，最近被认为是生物燃料生产的理想生物质原料，这激发了人们提高其生产力的兴趣。根据之前对陆生植物的研究，已知与植物共存的微生物对其生长有显著影响，因此本研究试图了解浮萍的植物 - 微生物相互作用，重点关注生长促进/抑制作用，以便评估通过改变共存细菌群落来加速浮萍生产的可能性。
将无菌浮萍与从各种水生环境中收集的细菌群落共同培养，与无菌对照相比，浮萍生长变化范围为 -24%至 +14%。从促进生长和抑制生长的群落中分离出许多细菌菌株，并检测它们对浮萍生长的共存影响。无论来源如何，每种菌株在与浮萍单独共同培养时都表现出促进、抑制或中性作用。为了进一步分析群落中这些细菌菌株之间的相互作用，将促进生长和抑制生长的菌株的二元组合与无菌浮萍共同培养，结果表明促进 - 促进或抑制 - 抑制菌株组合通常表现出与单个菌株相似的效果。然而，促进 - 抑制菌株组合往往表现出抑制作用，而只有H3在所有测试组合中都发挥了其促进植物生长的作用。
当浮萍与环境细菌群落共同培养时，观察到生物量生产有显著变化。群落中的促进、中性和抑制细菌将协同决定其效果。结果表明通过调节共存细菌群落来提高浮萍生物量生产的可能性。
