In vitro propagation and life cycle of the arbuscular mycorrhizal fungus Glomus etunicatum
In vitro propagation and life cycle of the arbuscular mycorrhizal fungus Glomus etunicatum
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DOI：
10.1017/s0953756299008801
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发表时间：
1999-12
期刊：
影响因子：
2.5
通讯作者：
T. Pawlowska;D. Douds;I. Charvat
中科院分区：
文献类型：
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作者：
T. Pawlowska;D. Douds;I. Charvat
由于能够在体外成功繁殖和研究的物种数量有限，阻碍了对丛枝菌根真菌生物学的了解。我们报道了与切除的 Ri T-DNA 转化的胡萝卜根相关的单细胞培养物的建立。真菌可以使用单细胞形成的休眠孢子和/或定植的根片段在体外繁殖。用 10 mM MES (pH 6) 或 MOPSO (pH 6.5) 缓冲的改良 White 培养基最适合宿主根部生长以及 G. etunicatum 孢子萌发和菌根形成。体外形成的休眠孢子的数量与丛枝菌根结构（包括丛枝和囊泡）所占据的根的长度呈正相关。在根部接种后两周内，孢子首先出现在双重培养物中。孢子形成是异步的并持续到根衰老。在应用的培养条件下，孢子在起始后 5-7 天内达到成熟外观。大约 6% 的单胞孢子在其发育的不同阶段失败。尽管体外形成的 G. etunicatum 孢子与土传接种物表现出总体形态和解剖学相似性，但它们比土传接种物明显更小且孢子壁更厚。因此，在利用体外系统作为土壤中球菌生长和发育的模型时应谨慎。
Progress in understanding the biology of arbuscular mycorrhizal fungi is hampered by the limited number of species that can be successfully propagated and studied in vitro . We report the establishment of monoxenic cultures of Glomus etunicatum in association with excised Ri T-DNA transformed carrot roots. The fungus can be propagated in vitro using monoxenically formed resting spores and/or colonized root fragments. Modified White's medium buffered with 10 mM MES (pH 6) or MOPSO (pH 6.5) was most optimal for the host root growth as well as for G. etunicatum spore germination and mycorrhiza formation. The number of resting spores formed in vitro correlated positively with the length of roots occupied by arbuscular mycorrhizal structures, including arbuscules and vesicles. Spores first appeared in dual cultures within two weeks of root inoculation. Sporulation was asynchronous and continued until root senescence. Under applied culture conditions, spores achieved mature appearance within 5–7 d after their initiation. Approximately 6% of monoxenic spores were aborted at different stages of their development. Although G. etunicatum spores formed in vitro exhibited general morphological and anatomical similarity to soil-borne inoculum, they were significantly smaller and had thicker spore walls than their soil-borne counterparts. Caution should, therefore, be exercised in utilizing the in vitro system as a model of growth and development of glomalean fungi in soil.