Abstract

The floral microbiome is of significant relevance to plant reproduction and crop productivity. While plant genotype is key to floral microbiome assembly, whether and how genotypic variation in floral traits and plant-level mutualistic and antagonistic interactions at the rhizosphere and phyllosphere influence the microbiome in the anthosphere remain little known. Using a factorial field experiment that manipulated biotic interactions belowground (mycorrhizae treatments) and aboveground (herbivory treatments) in three strawberry genotypes, we assessed how genotypic variation in flower abundance and size and plant-level biotic interactions influence the bidirectional relationships between floral volatile organic compounds (VOCs) and the floral microbiome using structural equation modeling. We found that plant genotype played a stronger role, overall, in shaping the floral microbiome than biotic interactions with mycorrhizae and herbivores. Genotypic variation in flower abundance and size influenced the emission of floral VOCs, especially terpenes (e.g. α- and β-pinene, ocimene isomers) and benzenoids (e.g. p-anisaldehyde, benzaldehyde), which in turn affected floral bacterial and fungal communities. While the effects of biotic interactions on floral traits including VOCs were weak, mycorrhizae treatments (mycorrhizae and herbivory + mycorrhizae) affected the fungal community composition in flowers. These findings improve our understanding of the mechanisms by which plant genotype influences floral microbiome assembly and provide the first evidence that biotic interactions in the rhizosphere and phyllosphere can influence the floral microbiome, and offer important insights into agricultural microbiomes.

中文翻译：

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与草莓中食草动物和菌根的相互作用相比，花卉挥发物的基因型变异对花卉微生物组的影响更大

摘要

花微生物组与植物繁殖和作物生产力具有重要意义。虽然植物基因型是花卉微生物组组装的关键，但花卉性状的基因型变异以及根际和叶际的植物水平互惠和拮抗相互作用是否以及如何影响植物圈中的微生物组仍然鲜为人知。使用在三种草莓基因型中操纵地下（菌根处理）和地上（食草处理）生物相互作用的因子田间实验，我们评估了花丰度和大小的基因型变异以及植物水平的生物相互作用如何影响花卉挥发性有机化合物之间的双向关系（VOC）和使用结构方程建模的花卉微生物组。我们发现植物基因型总体上发挥了更大的作用，在塑造花卉微生物组方面，与菌根和食草动物的生物相互作用相比。花丰度和大小的基因型变异影响了花VOCs的排放，尤其是萜烯（例如α-和β-蒎烯、罗勒烯异构体）和苯类（例如对茴香醛、苯甲醛），进而影响了花卉细菌和真菌群落。虽然生物相互作用对包括 VOC 在内的花卉性状的影响较弱，但菌根处理（菌根和食草 + 菌根）影响了花卉中的真菌群落组成。这些发现提高了我们对植物基因型影响花卉微生物组组装机制的理解，并提供了第一个证据表明根际和叶际中的生物相互作用可以影响花卉微生物组，