Application of in vitro methods to study carbon uptake and transport by AM fungi
Application of in vitro methods to study carbon uptake and transport by AM fungi
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DOI：
10.1023/a:1026466802354
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发表时间：
2000-01-01
期刊：
影响因子：
4.9
通讯作者：
Shachar-Hill, Y
中科院分区：
文献类型：
--
作者：
Douds, DD;Pfeffer, PE;Shachar-Hill, Y
正如多室根室在研究土壤中丛枝菌根 [AM] 真菌养分吸收方面比标准塑料盆具有优势一样，分体板体外系统在研究 AM 真菌的生理学方面也比标准双培养系统具有优势。我们使用 Ri T-DNA 转化的胡萝卜根和根内球囊霉的分板培养系统（其中只有真菌可以进入远端隔室）来研究芽管以及根外和根内菌丝吸收 C-13 标记底物的能力。将标记的底物添加到板隔板的一侧，并将板孵育 8 周，同时真菌在排除根的一侧增殖。然后从板上回收组织并通过核磁共振波谱进行检查。结果表明，不同形态阶段的真菌吸收这些底物的能力不同，最显着的是，根内菌丝吸收己糖，而根外菌丝则不能。此外，核磁共振研究表明，自由基内菌丝积极合成脂质，而自由基外菌丝则不然。这些数据表明，AM 真菌的最终无菌培养不仅仅是找到合适的生长底物的问题。必须克服遗传调控，使自由基外菌丝在 C 吸收和代谢方面表现得像自由基内菌丝。
Just as multi-compartmented root chambers have advantages over standard plastic pots for the study of nutrient uptake by arbuscular mycorrhizal [AM] fungi in soil, so the split-plate in vitro system has advantages over the standard dual culture system for the study of the physiology of AM fungi. We used the split-plate culture system of Ri T-DNA transformed Daucus carota L. roots and Glomus intraradices Schenck & Smith, in which only the fungus has access to the distal compartment, to study the ability of germ tubes and extraradical and intraradical hyphae to take up C-13-labeled substrates. Labeled substrates were added to one side of the plate divider and plates were incubated for 8 weeks while the fungus proliferated on the side from which the root was excluded. Tissues then were recovered from the plate and examined via NMR spectroscopy. Results showed that the morphological phases of the fungus differed in their ability to take up these substrates, most notably that intraradical hyphae take up hexose while extraradical hyphae cannot. In addition, NMR studies indicated that intraradical hyphae actively synthesized lipids while extraradical hyphae did not. These data show that eventual axenic culture of AM fungi is more than a matter of finding the proper substrate for growth. Genetic regulation must be overcome to make extraradical hyphae behave like intraradical hyphae in terms of C uptake and metabolism.