Department of Plant Pathology, University of Minnesota, St. Paul, MN, USA.
J Appl Microbiol. 2013 May;114(5):1500-6. doi: 10.1111/jam.12164. Epub 2013 Mar 4.
To determine the identity and diversity of endophytes in soybean plants using culture-dependent (CD) and culture-independent (CI) methods.
Stem samples were collected from three field-grown soybean cultivars grown to a reproductive stage in Minnesota, USA. Samples were surface disinfested, and CD and CI methods were used to assess the endophytes. For the CD method, fungi were isolated and grouped based on colony morphology, and the rDNA ITS region was sequenced to identify the cultures. The most frequently isolated genera were Cladosporium (36%), Alternaria (13%), Diaporthe (9%) and Epicoccum (9%). For the CI method, DNA was extracted from the stems, and the ITS region was amplified, cloned and sequenced for identification. The most prevalent genus detected using CI method was Cladosporium (85%).
Soybean contains a diverse array of endophytic fungi that were identified in this study. The CD method detected greater endophyte diversity (H' = 2·12) than the CI method (H' = 0·66).
The results improve our understanding of the identity and diversity of endophytic fungi that likely have different kinds of interactions with soybean plants. The results suggest that CD and CI methods should be used to study endophytes in soybean and perhaps other annual crop plants.
采用依赖培养（CD）和非依赖培养（CI）方法，确定大豆植物内生菌的种类和多样性。
从美国明尼苏达州生长至生殖阶段的 3 种田间大豆品种的茎部采集样本。对样本进行表面消毒，分别采用 CD 和 CI 方法评估内生菌。采用 CD 方法，根据菌落形态分离和分组真菌，并对 rDNA ITS 区进行测序以鉴定培养物。最常分离的属为链格孢属（36%）、交链孢属（13%）、拟茎点霉属（9%）和层出镰孢属（9%）。采用 CI 方法，从茎部提取 DNA，扩增、克隆和测序 ITS 区进行鉴定。CI 方法检测到的最普遍属为链格孢属（85%）。
本研究鉴定了大豆中存在的多种内生真菌。依赖培养方法检测到的内生菌多样性更高（H'=2.12），而非依赖培养方法（H'=0.66）检测到的多样性较低。
研究结果增进了我们对可能与大豆植物具有不同相互作用的内生真菌种类和多样性的了解。研究结果表明，应采用 CD 和 CI 方法来研究大豆及其它一年生作物植物中的内生菌。
