菌根真菌对有机氮吸收利用的研究进展

Recent advances in organic N absorption and utilization by mycorrhizal fungus

综述了菌根真菌对有机氮的吸收利用在植物生理学、分子水平及实验装置方面国内外近年来取得的一些研究成果.菌根真菌吸收有机氮后能向宿主植物转运,其中丛枝菌根真菌吸收氨基氮后在根外菌丝中合成载体———精氨酸(Arg),它既能在根外菌丝(ERM)和根内菌丝(IRM)间双向运转,又能在根内菌丝中经尿素循环分解成NH4+,作为氮源整合入根内菌丝中的其他氨基酸或通过NH4+-转运蛋白转运给宿主植物.已经从菌根真菌中克隆出或检测到表达一些与氮代谢相关的基因.与研究需求相适应的实验装置也在不断发展.

A comprehensive review of recent advances in physiology biochemistry and molecular biology about organic N absorption and utilization by mycorrhizal fungus,the basis for further study of clarifying mechanisms of mycorrhizal fungi uptake and utilization organic nitrogen were provided.One of mycorrhizal fungus,arbuscular mycorrhizal fungi assimilated amino acid,in the extraradical mycelium synthetized organic N carrier： Arg,which could bidirectionally ran between the intraradical mycelium（IRM） and the extraradical mycelium（ERM） was studied.Arg in the IRM was decomposed into ure by urea cycle and released NH＋4.NH＋4 as nitrogen source was utilized to form other amino acid in the IRM or transfered to its host plant by NH＋4 translocator.Besides,arbuscular mycorrhizal fungi could transfer substrantial amounts of nitrogen to their host plant from organic material.In recent years,it was accumulated lots of data on physiology as well as molecular biology of the organic N assimilation.There were many related N uptake and metabolism genes in mycorrhizal fungus which had been cloned and characterized or whose expression had been determined.To satisfy the demands for study,test equipments were also changed.