Data_Sheet_1_The Plant Growth-Promoting Fungus MF23 (Mycena sp.) Increases Production of Dendrobium officinale (Orchidaceae) by Affecting Nitrogen Uptake and NH4+ Assimilation.zip

Dendrobium officinale Kimura et Migo is a traditional and scarce medicinal orchid in China. Mycorrhizal fungi could supply nitrogen (N) to orchids for seed germination and seedling recruitment. However, the N transport mechanism between orchids and the fungus is poorly understand. Early studies found that the fungus MF23 (Mycena sp.) could promote the growth of D. officinale. To better dissect the molecular interactions involved in N transport between D. officinale and MF23, transcriptome and metabolome analyses were conducted on conventional and mycorrhizal cultivations of D. officinale. Moreover, validation tests were carried out in the greenhouse to measure net fluxes of NO3− and NH4+ of roots by a non-invasive micro-test technology (NMT), determine N assimilation enzyme activity by the ELISA, and analyze the expression level of differentially expressed genes (DEGs) of N transporters and DEGs involved in N metabolism by RT-qPCR. Combined transcriptome and metabolome analyses showed that MF23 may influence N metabolism in D. officinale. The expression of DoNAR2.1 (nitrate transporter-activating protein), DoAMT11 (ammonium transporter), DoATFs (amino acid transporters), DoOPTs (oligopeptide transporters), and DoGDHs (glutamate dehydrogenases) in symbiotic D. officinale was upregulated. NMT results showed a preference for NH4+ in D. officinale and indicated that MF23 could promote the uptake of NO3− andNH4+, especially for NH4+. ELISA results showed that MF23 could increase the activity of glutamine synthetase (GS) and glutamate dehydrogenase. This study suggested that MF23 increases the production of D. officinale by affecting N uptake and NH4+ assimilation capacity.

铁皮石斛（Dendrobium officinale Kimura et Migo）是中国传统珍稀药用兰科植物。菌根真菌（mycorrhizal fungi）可向兰科植物提供氮（N），以支持其种子萌发与幼苗定植。然而，兰科植物与真菌间的氮转运机制尚不清楚。早期研究表明，真菌MF23（小菇属（Mycena sp.））可促进铁皮石斛的生长。为深入解析铁皮石斛与MF23之间氮转运相关的分子互作机制，研究人员对常规栽培与菌根共生栽培的铁皮石斛开展了转录组与代谢组分析。此外，研究人员在温室中开展验证实验：采用非损伤微测技术（non-invasive micro-test technology, NMT）测定根系硝酸根（NO3−）与铵根（NH4+）的净通量，通过酶联免疫吸附测定（enzyme-linked immunosorbent assay, ELISA）检测氮同化酶活性，并通过实时定量聚合酶链反应（real-time quantitative polymerase chain reaction, RT-qPCR）分析氮转运蛋白编码差异表达基因（differentially expressed genes, DEGs）及氮代谢相关差异表达基因的表达水平。联合转录组与代谢组分析结果显示，MF23可影响铁皮石斛的氮代谢过程。共生状态下的铁皮石斛中，DoNAR2.1（硝酸转运激活蛋白）、DoAMT11（铵转运蛋白）、DoATFs（氨基酸转运蛋白）、DoOPTs（寡肽转运蛋白）及DoGDHs（谷氨酸脱氢酶）的表达均显著上调。非损伤微测技术结果显示，铁皮石斛对铵根具有吸收偏好性，且MF23可促进其对硝酸根与铵根的吸收，尤以铵根吸收的促进效果最为显著。酶联免疫吸附测定结果表明，MF23可提升谷氨酰胺合成酶（glutamine synthetase, GS）与谷氨酸脱氢酶的活性。本研究表明，MF23可通过影响铁皮石斛的氮吸收能力与铵根同化效率，提升其产量。