Department of Plant Pathology and Ecology, The Connecticut Agricultural Experiment Station, New Haven, CT, 06511, USA.
Department of Environmental Sciences, The Connecticut Agricultural Experiment Station, New Haven, CT, 06511, USA.
ISME J. 2021 Jan;15(1):318-329. doi: 10.1038/s41396-020-00784-y. Epub 2020 Oct 6.
Plant microbiomes have important roles in plant health and productivity. However, despite flowers being directly linked to reproductive outcomes, little is known about the microbiomes of flowers and their potential interaction with pathogen infection. Here, we investigated the temporal spatial dynamics of the apple stigma microbiome when challenged with a phytopathogen Erwinia amylovora, the causal agent of fire blight disease. We profiled the microbiome from the stigmas of individual flowers, greatly increasing the resolution at which we can characterize shifts in the composition of the microbiome. Individual flowers harbored unique microbiomes at the operational taxonomic unit level. However, taxonomic analysis of community succession showed a population gradually dominated by bacteria within the families Enterobacteriaceae and Pseudomonadaceae. Flowers inoculated with E. amylovora established large populations of the phytopathogen, with pathogen-specific gene counts of >3.0 × 10 in 90% of the flowers. Yet, only 42% of inoculated flowers later developed fire blight symptoms. This reveals that pathogen abundance on the stigma is not sufficient to predict disease outcome. Our data demonstrate that apple flowers represent an excellent model in which to characterize how plant microbiomes establish, develop, and correlate with biological processes such as disease progression in an experimentally tractable plant organ.
植物微生物组在植物健康和生产力方面发挥着重要作用。然而，尽管花朵与生殖结果直接相关，但对于花朵的微生物组及其与病原体感染的潜在相互作用知之甚少。在这里，我们研究了苹果柱头微生物组在受到植物病原菌梨火疫病菌（Erwinia amylovora）挑战时的时空动态，该病原菌是火疫病的致病因子。我们从单个花朵的柱头上对微生物组进行了分析，极大地提高了我们能够描述微生物组组成变化的分辨率。在操作分类单元水平上，单个花朵具有独特的微生物组。然而，群落演替的分类分析表明，细菌种群逐渐由肠杆菌科和假单胞菌科内的细菌主导。用 E. amylovora 接种的花朵建立了大量的植物病原菌，在 90%的花朵中，病原菌特异性基因的计数超过 3.0×10。然而，只有 42%的接种花朵后来出现火疫病症状。这表明柱头病原菌的丰度不足以预测疾病结果。我们的数据表明，苹果花是一个很好的模型，可以用来描述植物微生物组如何在实验上可处理的植物器官中建立、发展，并与疾病进展等生物学过程相关联。
