A simple model system for identifying arbuscular mycorrhizal fungal taxa that actively colonize rice (Oryza sativa L.) roots grown in field soil
A simple model system for identifying arbuscular mycorrhizal fungal taxa that actively colonize rice (Oryza sativa L.) roots grown in field soil
复制标题
一个简单的模型系统，用于识别丛枝菌根真菌类群，该类群积极定植于田间土壤中生长的水稻（Oryza sativa L.）根部
DOI：
10.1080/00380768.2016.1277156
复制
发表时间：
2017
影响因子：
2
通讯作者：
S. Morimoto
中科院分区：
文献类型：
--
作者：
Yoshihiro Kobae;R. Ohtomo;N. Oka;S. Morimoto
摘要 即使是田间土壤中几厘米的根部也可能被遗传多样性的丛枝菌根 (AM) 真菌定殖。根部 AM 真菌的 DNA 序列表明了真菌的身份；然而，很难确定哪些 AM 真菌类群具有生理活性。在本研究中，我们利用了水稻（Oryza sativa L.）菌根根的特征，通过真菌琥珀酸脱氢酶活性的组织化学染色（活体染色）可以很容易地检测到根部的活跃定植，并且根部的单个活跃定植区域（感染单位）很少合并。将含有活性感染单位的根段（< 3 mm）解剖并压扁，使用真菌通用引物扩增大亚基（LSU）核糖体RNA基因（rDNA），并通过桑格测序直接确定序列。所有获得的定植区域序列均源自球囊真菌。系统发育分析表明，不同进化枝中活跃定植位点内的 LSU-rDNA 异质性水平不同。这项研究中提出的方法为研究人员提供了一种新的工具来研究根部中具有生理活性的AM真菌的DNA信息，而影响活跃定殖的遗传多样性的因素仍有待阐明。
ABSTRACT Even a few centimeters of roots in field soils can be colonized by genetically diverse arbuscular mycorrhizal (AM) fungi. The DNA sequences of AM fungi in roots suggest the fungal identities; however, it is difficult to determine which AM fungal taxa are physiologically active. In this study, we took advantage of the characteristics of rice (Oryza sativa L.) mycorrhizal roots, in which active colonization in roots is easily detected via histochemical staining of fungal succinate dehydrogenase activity (vital staining) and individual active colonization regions (infection units) in roots rarely coalesce. Root segments (< 3 mm) containing an active infection unit were dissected and squashed, large subunit (LSU) ribosomal RNA genes (rDNAs) were amplified using fungal universal primers and the sequences were directly determined by Sanger sequencing. All obtained sequences of colonization regions were of glomeromycotan origin. Phylogenetic analysis revealed that the levels of LSU-rDNA heterogeneity within an active colonization site were different among different clades. The methodology presented in this study offers researchers a novel tool for investigating the DNA information of physiologically active AM fungi in roots, whereas the factors that affect genetic diversity among active colonization remain to be clarified.