Identity, Diversity, and Molecular Phylogeny of the Endophytic Mycobiota in the Roots of Rare Wild Rice (Oryza granulate) from a Nature Reserve in Yunnan, China
Identity, Diversity, and Molecular Phylogeny of the Endophytic Mycobiota in the Roots of Rare Wild Rice (Oryza granulate) from a Nature Reserve in Yunnan, China
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DOI：
10.1128/aem.01911-09
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发表时间：
2009-12
影响因子：
4.4
通讯作者：
Zhilin Yuan;Chulong Zhang;F. Lin;C. Kubicek
中科院分区：
文献类型：
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作者：
Zhilin Yuan;Chulong Zhang;F. Lin;C. Kubicek
摘要水稻(Oryza sativa L.)在全球范围内，是最重要的粮食作物之一。虽然人们对与水稻相关的内生真菌和细菌进行了研究，但对中国野生稻(Oryza Ranulate)的内生真菌却知之甚少。本研究采用显微镜观察、培养、生态指标和直接聚合酶链式反应相结合的方法，对颗粒稻根部内生真菌区系进行了研究。显微镜观察证实根组织中普遍存在暗隔状内生菌(DSE)和菌核状结构。从15个野生稻植株的204个根段中分离到58个菌株，其中记录了31个基于ITS的基因型。最好的BLAST匹配表明，所遇到的所有分类群中有34.5%可能是迄今未描述的物种。大多数真菌的分离频率很低。生态指数的计算和分类群积累曲线的估算表明，真菌物种具有较高的多样性。此外，还采用了一种与培养无关的方法来分析内生真菌群落。构建了3个克隆文库。以90%的相似性为阈值，在186个阳性克隆中发现了35个潜在不同的序列(系统类型)。系统发育分析表明，发现频率较高的无性系被归类为担子菌门，60.2%的无性系隶属于未知类群。Exophiala、Cladhialophora、Harophora、Periconia macspinosa和Ceratobasidium/Rhizoctonia复合体可能是潜在的DSE类群。对这两种方法所表现的真菌群落的比较显示出不同的真菌群，只有少数分类群重叠。我们的发现表明野生稻根中存在一个复杂而丰富的内生真菌群落，从而为建立植物-真菌相互作用的新模式提供了潜在的生物资源。
ABSTRACT Rice (Oryza sativa L.) is, on a global scale, one of the most important food crops. Although endophytic fungi and bacteria associated with rice have been investigated, little is known about the endophytic fungi of wild rice (Oryza granulate) in China. Here we studied the root endophytic mycobiota residing in roots of O. granulate by the use of an integrated approach consisting of microscopy, cultivation, ecological indices, and direct PCR. Microscopy confirmed the ubiquitousness of dark septate endophytes (DSEs) and sclerotium-like structures in root tissues. Isolations from 204 root segments from 15 wild rice plants yielded 58 isolates, for which 31 internal transcribed spacer (ITS)-based genotypes were recorded. The best BLAST match indicated that 34.5% of all taxa encountered may represent hitherto undescribed species. Most of the fungi were isolated with a very low frequency. Calculation of ecological indices and estimation of taxon accumulation curves indicated a high diversity of fungal species. A culture-independent approach was also performed to analyze the endophytic fungal community. Three individual clone libraries were constructed. Using a threshold of 90% similarity, 35 potentially different sequences (phylotypes) were found among 186 positive clones. Phylogenetic analysis showed that frequently detected clones were classified as Basidiomycota, and 60.2% of total analyzed clones were affiliated with unknown taxa. Exophiala, Cladophialophora, Harpophora, Periconia macrospinosa, and the Ceratobasidium/Rhizoctonia complex may act as potential DSE groups. A comparison of the fungal communities characterized by the two approaches demonstrated distinctive fungal groups, and only a few taxa overlapped. Our findings indicate a complex and rich endophytic fungal consortium in wild rice roots, thus offering a potential bioresource for establishing a novel model of plant-fungal mutualistic interactions.