Department of Plant Pathology and Ecology, The Connecticut Agricultural Experiment Station, New Haven, Connecticut, USA.
Department of Entomology, The Connecticut Agricultural Experiment Station, New Haven, Connecticut, USA.
Environ Microbiol. 2024 Oct;26(10):e16702. doi: 10.1111/1462-2920.16702.
Flowers serve as hubs for biotic interactions with pollinators and microbes, which can significantly impact plant reproduction and health. Previous studies have shown that the flower microbiota undergoes dynamic assembly processes during anthesis. However, the influence of foraging pollinators on the assembly and dispersal of the flower microbiota and the transmission of plant pathogens remains poorly understood. In this study, we used insect exclusion netting to investigate the role of pollinators in the assembly of the microbiota on apple stigma and the transmission of the fire blight pathogen Erwinia amylovora. We found that excluding pollinators had a minor impact on the community diversity and composition of the apple stigma microbiota, while the flower's developmental stage had a strong influence. Additionally, pollinator exclusion altered bacterial dispersal and the relative abundance of different bacterial species, including E. amylovora, suggesting that pollinators play a role in transmitting plant pathogens. Using a reporter system, we demonstrated that bumble bees can transmit the fire blight pathogen from an infected flower under controlled growth conditions. Our study highlights the importance of intrinsic and pollinator-independent microbes as sources of inoculum for the stigma microbiota and underscores the role of foraging pollinators in vectoring plant pathogens.
花作为与传粉者和微生物相互作用的中心，这些相互作用可以显著影响植物的繁殖和健康。先前的研究表明，花微生物组在开花期间经历动态组装过程。然而，传粉者对花微生物组的组装和分散以及植物病原菌的传播的影响仍知之甚少。在这项研究中，我们使用昆虫排斥网来研究传粉者在苹果柱头微生物组的组装和火疫病病原菌 Erwinia amylovora 的传播中的作用。我们发现，排斥传粉者对苹果柱头微生物组的群落多样性和组成的影响较小，而花的发育阶段有很大的影响。此外，传粉者的排斥改变了细菌的分散和不同细菌物种的相对丰度，包括 E. amylovora，这表明传粉者在传播植物病原菌方面发挥了作用。使用报告系统，我们证明了大黄蜂可以在受控生长条件下将火疫病病原菌从感染的花朵中传播出去。我们的研究强调了内在和与传粉者无关的微生物作为柱头微生物组接种体来源的重要性，并强调了觅食传粉者在传播植物病原菌方面的作用。
