College of Plant Protection, Gansu Agricultural University and Biocontol Engineering Laboratory of Crop Diseases and Pests of Gansu Province, Lanzhou, Gansu, China.
College of Agriculture and Biotechnology, Hexi University, Zhangye, Gansu, China.
Microbiologyopen. 2018 Dec;7(6):e00609. doi: 10.1002/mbo3.609. Epub 2018 Mar 23.
Fungi are an integral component of the plant microbiome. However, the composition and variation in the fungal communities (mycobiota) associated with seeds are poorly understood. In this study, we investigated the mycobiota of 11 maize seed samples with storage times ranging from 6 months to 12 years. Mycobiota were characterized by a culture-based approach, and fungal species were identified through rDNA-ITS sequence analyses. From a total of 169 pure fungal isolates obtained from both the seed surface and internal tissues, we identified 16 distinct species (belonging to 10 genera) associated with maize seeds, all but one of which were ascomycetes. Among these species, seven were exclusively isolated from internal tissues, two species were isolated only from the seed surface, and another six species were isolated from both the surface and internal tissues. Aspergillus niger was consistently found under all storage conditions and dominated fungal communities with a relative abundance of 36%-100%. Species of Fusarium (9%-40%) and Penicillium (9%-20%) were also frequently isolated, but other species appeared sporadically and were isolated from fewer than three seed stocks. According to our results, while the overall incidence of fungal infection generally declined with storage time, there was no consistent association between seed storage time and fungal species richness or relative abundance; furthermore, the composition of the mycobiota associated with maize seeds was highly variable among the samples. The detection of the four major mycotoxigenic fungal genera, specifically Aspergillus, Fusarium, Penicillium, and Alternaria, was alarming, and the isolation of a potential controlling agent as well as information about their temporal occurrence will contribute to the management of mycotoxins in the future.
真菌是植物微生物组的一个组成部分。然而，与种子相关的真菌群落（真菌区系）的组成和变化还知之甚少。在这项研究中，我们调查了 11 个玉米种子样本的真菌区系，这些样本的储存时间从 6 个月到 12 年不等。通过基于培养的方法来描述真菌区系，通过 rDNA-ITS 序列分析鉴定真菌物种。从总共从种子表面和内部组织获得的 169 个纯真菌分离物中，我们鉴定出与玉米种子相关的 16 个不同物种（属于 10 个属），除了一个之外，其余都是子囊菌。在这些物种中，有七个是专门从内部组织中分离出来的，两个物种仅从种子表面分离出来，另外六个物种从表面和内部组织中分离出来。黑曲霉在所有储存条件下都被发现，并且在真菌群落中占主导地位，相对丰度为 36%-100%。镰孢菌（9%-40%）和青霉（9%-20%）的物种也经常被分离出来，但其他物种则偶尔出现，并且从不到三个种子库中分离出来。根据我们的结果，虽然真菌感染的总体发生率通常随储存时间的延长而降低，但种子储存时间与真菌物种丰富度或相对丰度之间没有一致的关联；此外，与玉米种子相关的真菌区系的组成在样本之间高度可变。检测到四个主要产毒真菌属，即曲霉属、镰孢菌属、青霉属和交链孢属，这令人警惕，分离出潜在的控制剂以及它们的时间发生信息将有助于未来对霉菌毒素的管理。
