Defoliation effects on the community structure of arbuscular mycorrhizal fungi based on 18S rDNA sequences
Defoliation effects on the community structure of arbuscular mycorrhizal fungi based on 18S rDNA sequences
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DOI：
10.1007/s00572-003-0286-x
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发表时间：
2004-12-01
期刊：
影响因子：
3.9
通讯作者：
Sugawara, K
中科院分区：
文献类型：
--
作者：
Saito, K;Suyama, Y;Sugawara, K
通过对草地植物根系AM真菌群落结构的研究，探讨了落叶对草地AM真菌群落的影响，并测定了草地植物根系的碳水化合物平衡。我们专注于两种植物物种占主导地位的日本本土草原：放牧不耐受物种芒和放牧耐受物种结缕草。利用18S rRNA基因序列分析了AM真菌的群落结构。在这两种植物的优势真菌群是球囊分支，这是根据遗传距离和拓扑结构分为几个系统发育组。在芒草根中，Glomus-Ab、Glomus-Ac和Glomus-Ad组几乎相等地被检测到。结缕草根中Glomus-Ab类群占优势。落叶对AM真菌群落结构的影响因植物种类而异。在芒草根，根长度的百分比（%RLC）由球囊霉-Ac和球囊霉-Ad组定殖显着降低落叶处理。另一方面，AM真菌组组成的结缕草根不受落叶，除了在最后一个采样日期。Glomus-Ac和Glomus-Ad降低的%RLC与宿主植物中非结构性碳水化合物（NSC）水平的降低相一致;此外，发现%RLC与某些NSC水平之间存在显著的正相关。另一方面，两种植物物种中Glomus-Ab的%RLC不受NSC水平的影响。这些结果表明，AM真菌群体有不同的碳水化合物的需求从寄主植物。
The effects of defoliation on arbuscular mycorrhizal (AM) associations in the field were investigated in terms of the community structure of AM fungi colonizing roots of grassland plants; the carbohydrate balance of the host plants was also determined. We focused on two plant species dominating Japanese native grasslands: the grazing-intolerant species Miscanthus sinensis and the grazing-tolerant species Zoysia japonica. Community structures of AM fungi were determined from 18S rRNA gene sequences. The dominant fungal group in both plant species was the Glomus clade, which was classified into several phylogenetic groups based on genetic distances and topology. In Miscanthus roots, the Glomus-Ab, Glomus-Ac, and Glomus-Ad groups were detected almost equally. In Zoysia roots, the Glomus-Ab group was dominant. Defoliation effects on the community structure of AM fungi differed between the plant species. In Miscanthus roots, the percentage of root length colonized (%RLC) by the Glomus-Ac and Glomus-Ad groups was significantly reduced by defoliation treatment. On the other hand, AM fungal group composition in Zoysia roots was unaffected by defoliation except on the last sampling date. Decreased %RLC by Glomus-Ac and Glomus-Ad coincided with decreased non-structural carbohydrate (NSC) levels in host plants; also, significant positive correlations were found between the %RLC and some NSC levels. On the other hand, the %RLC by Glomus-Ab in both plant species was unaffected by the NSC level. These results suggest that AM fungal groups have different carbohydrate requirements from host plants.