Gous Annemarie, Swanevelder Dirk Z H, Eardley Connal D, Willows-Munro Sandi
Biotechnology Platform Agricultural Research Council Pretoria South Africa.
School of Life Sciences University of KwaZulu-Natal Scottsville, Pietermaritzburg South Africa.
Evol Appl. 2018 Nov 13;12(2):187-197. doi: 10.1111/eva.12707. eCollection 2019 Feb.
Pollination is a key component in agricultural food production and ecosystem maintenance, with plant-pollinator interactions an important research theme in ecological and evolutionary studies. Natural history collections provide unique access to samples collected at different spatial and temporal scales. Identification of the plant origins of pollen trapped on the bodies of pollinators in these collections provides insight into historic plant communities and pollinators' preferred floral taxa. In this study, pollen was sampled from Smith bees from the National Collection of Insects, South Africa, spanning 93 years. Three barcode regions, the internal transcribed spacer 1 and 2 (ITS1 and ITS2) and ribulose-1,5-biphosphate carboxylase (), were sequenced from mixed pollen samples using a next-generation sequencing approach (MiSeq, Illumina). Sequenced reads were compared to sequence reference databases that were generated by extracting sequence and taxonomic data from GenBank. ITS1 and ITS2 were amplified successfully across all (or most) samples, while performed inconsistently. Age of sample had no impact on sequencing success. Plant classification was more informative using ITS2 than ITS1 barcode data. This study also highlights the need for comprehensive reference databases as limited local plant sequence representation in reference databases resulted in higher-level taxon classifications being more confidently interpreted. The results showed that small, insect-carried pollen samples from historic bee specimens collected from as early as 1914 can be used to obtain pollen metabarcodes. DNA metabarcoding of mixed origin pollen samples provided a faster, more accurate method of determining pollen provenance, without the need for expert palynologists. The use of historic collections to sample pollen directly from pollinators provided additional value to these collections. Sampling pollen from historic collections can potentially provide the spatial and temporal scales for investigations into changes in plant community structure or pollinator floral choice in the face of global climate change.
授粉是农业粮食生产和生态系统维持的关键组成部分，植物与传粉者的相互作用是生态和进化研究中的一个重要主题。自然历史标本馆提供了获取在不同时空尺度上采集的样本的独特途径。确定保存在这些标本馆中传粉者身体上捕获的花粉的植物来源，有助于了解历史植物群落以及传粉者偏好的花卉分类群。在本研究中，从南非国家昆虫收藏馆的史密斯蜜蜂身上采集花粉样本，时间跨度达93年。使用下一代测序方法（MiSeq，Illumina）从混合花粉样本中对三个条形码区域，即内转录间隔区1和2（ITS1和ITS2）以及核酮糖-1,5-二磷酸羧化酶（）进行测序。将测序读数与通过从GenBank提取序列和分类数据生成的序列参考数据库进行比较。ITS1和ITS2在所有（或大多数）样本中均成功扩增，而的扩增情况不一致。样本年龄对测序成功率没有影响。使用ITS2条形码数据进行植物分类比ITS1更具信息性。本研究还强调了建立全面参考数据库的必要性，因为参考数据库中有限的本地植物序列表示导致更高级别的分类群分类能得到更可靠的解释。结果表明，早在1914年采集的历史蜜蜂标本中携带的小昆虫花粉样本可用于获得花粉代谢条形码。混合来源花粉样本的DNA代谢条形码分析提供了一种更快、更准确的确定花粉来源的方法，无需专业孢粉学家。利用历史标本馆直接从传粉者身上采集花粉样本为这些标本馆增添了额外价值。从历史标本馆中采集花粉样本有可能为研究全球气候变化背景下植物群落结构变化或传粉者花卉选择提供时空尺度。
