Growth Promotion of Giant Duckweed Spirodela polyrhiza (Lemnaceae) by Ensifer sp. SP4 Through Enhancement of Nitrogen Metabolism and Photosynthesis
Growth Promotion of Giant Duckweed Spirodela polyrhiza (Lemnaceae) by Ensifer sp. SP4 Through Enhancement of Nitrogen Metabolism and Photosynthesis
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DOI：
10.1094/mpmi-06-21-0157-r
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发表时间：
2022-01-01
影响因子：
3.5
通讯作者：
Morikawa, Masaaki
中科院分区：
文献类型：
--
作者：
Toyama, Tadashi;Mori, Kazuhiro;Morikawa, Masaaki
浮萍是淡水水生生态系统中具有代表性的生产者，也为动物饲料、人类食品和生物燃料生产可持续的生物质，并有助于有效地处理废水；因此，提高浮萍的生产力是一个关键的挑战。植物生长促进细菌(PGPB)可以提高陆生植物的生产力，但浮萍与PGPB的相互作用尚不清楚，目前还没有研究浮萍与PGPB相互作用的分子机制。其中，一株为PGPB，ensfer sp.从巨型浮萍中分离到一株新菌株SP4，通过生理生化和代谢组学分析研究了SP4与多根螺旋藻之间的相互作用。在多根链霉菌与SP4共培养条件下，SP4使多根链霉菌的氮素、叶绿素、核酮糖-1，5-二磷酸羧基/加氧酶(Rubisco)含量和光合作用速率分别提高2.5、2.5、2.7和2.4倍。提高光合作用使多根链霉菌的相对生长速率和生物量生产力分别提高1.5倍和2.7倍。菌株SP4显著改变了多根链霉菌的代谢谱，尤其是氨基酸谱。氮稳定同位素分析表明，有机氮化合物从SP4向多根链霉菌转移。这些氮化合物，特别是谷氨酸，可能引发了光合作用和生长活性的增加。因此，我们提出了一个新的模型来解释伴生细菌Senfer sp.促进多根链霉菌生长的分子机制。SP4，它通过增强N化合物代谢和光合作用发生。我们的研究结果表明，ensfer sp.SP4是一种具有较高生物量、废水净化活性和CO2捕获率的新型菌种。
Duckweeds (Lemnaceae) are representative producers in fresh aquatic ecosystems and also yield sustainable biomass for animal feeds, human foods, and biofuels, and contribute toward effective wastewater treatment; thus, enhancing duckweed productivity is a critical challenge. Plant-growth -promoting bacteria (PGPB) can improve the productivity of terrestrial plants; however, duckweed-PGPB interactions remain unclear and no previous study has investigated the molecular mechanisms underlying duckweed-PGPB interaction. Herein, a PGPB, Ensifer sp. strain SP4, was newly isolated from giant duckweed (Spirodela polyrhiza), and the interactions between S. polyrhiza and SP4 were investigated through physiological, biochemical, and metabolomic analyses. In S. polyrhiza and SP4 coculture, SP4 increased the nitrogen (N), chlorophyll, and ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) contents and the photosynthesis rate of S. polyrhiza by 2.5-, 2.5-, 2.7-, and 2.4-fold, respectively. Elevated photosynthesis increased the relative growth rate and biomass productivity of S. polyrhiza by 1.5 and 2.7-fold, respectively. Strain SP4 significantly altered the metabolomic profile of S. polyrhiza, especially its amino acid profile. N stable isotope analysis revealed that organic N compounds were transferred from SP4 to S. polyrhiza. These N compounds, particularly glutamic acid, possibly triggered the increase in photosynthetic and growth activities. Accordingly, we propose a new model for the molecular mechanism underlying S. polyrhiza growth promotion by its associated bacteria Ensifer sp. SP4, which occurs through enhanced N compound metabolism and photosynthesis. Our findings show that Ensifer sp. SP4 is a promising PGPB for increasing biomass yield, wastewater purification activity, and CO2 capture of S. polyrhiza.