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通过15N和13C同位素标记证明了在丛枝菌根(arbuscular mycorrhiza,AM)菌丝内精氨酸(arginine,Arg)双向运转并分解为鸟氨酸(ornithine,Orn).离体菌根真菌Glomus intraradices和Ri T-DNA转化的胡萝卜根培养在两室(菌根室和真菌室)培养皿中.[15N/13C]Arg施加在菌根室或真菌室或非侵染根组织中.采用色质联用和液相色谱测定菌根和根外菌丝(extraradical mycelium,ERM)内自由氨基酸的含量和同位素标记.研究发现与外源性Arg相比,AM真菌ERM内Arg的15N标记在ERM培养于外源性氮源NH4+和尿素时是最高的.但是,外源性C源甘油施加于ERM对Arg的15N标记没有较大的影响.在此期间,ERM在培养于4mmol/L NH4+6周后,其中Arg从ERM运转至菌根组织,并使菌根组织自由氨基酸中Arg的水平增加至20%左右.同时通过[U-13C]Arg标记在真菌室或菌根室发现Arg可以沿AM真菌菌丝双向运转.被运转的Arg会进一步分解为Orn和尿素,因为[U-13C]或[U-15N/U-13C]Arg标记于真菌室后完整的[U-13C]或[U-15N/U-13C]Orn在菌根组织中产生.所以,Orn的生成标志着AM真菌氮代谢中发生了Arg的运转和分解代谢.
The 15N and 13C isotopes were used to demonstrate the arginine (Arg) biotransformation in arbuscular mycorrhizal (AM) mycelium and its decomposition to ornithine (Orn). The mycorrhizal fungi Glomus The intraradices and Ri T-DNA transformed carrot roots were cultured in Petri dishes (mycorrhoea and fungi) petri dishes. [15N / 13C] Arg was applied to the mycorrhoea or fungal compartment or non-infected root tissue. The contents of free amino acids and isotopes in mycorrhizal and extraradical mycelium (ERM) were determined by liquid chromatography.It was found that compared with the exogenous Arg, However, exogenous C-glycerol applied to ERM had no significant effect on Arg labeling of 15N.Moreover, ERM cultured in 4mmol / L NH4 + 6weeks Arg from arbuscular mycorrhizal (AMM) and Arg (arginine) were increased from ArM to mycorrhizal tissue and Arg in free amino acids of mycorrhizae increased to about 20% .At the same time, [Ar-13C] The mycelium runs bidirectionally, and Arg, which is run, breaks down further into Orn and urea because [U-13C] or [U-15 The complete [U-13C] or [U-15N / U-13C] Orn is produced in mycorrhizal tissue after Arg labeling in the fungal chamber.Thus, the production of Orn signals the occurrence of AM fungal nitrogen metabolism Arg’s functioning and catabolism.