In corn/maize, silks emerging from cobs capture pollen, and transmit resident sperm nuclei to eggs. There are > 20 million silks per U.S. maize acre. Fungal pathogens invade developing grain using silk channels, including Fusarium graminearum (Fg, temperate environments) and devastating carcinogen-producers (Africa/tropics). Fg contaminates cereal grains with mycotoxins, in particular Deoxynivalenol (DON), known for adverse health effects on humans and livestock. Fitness selection should promote defensive/healthy silks. Here, we report that maize silks, known as styles in other plants, possess complex and dynamic microbiomes at the critical pollen-fungal transmission interval (henceforth: transmitting style microbiome, TSM). Diverse maize genotypes were field-grown in two trial years. MiSeq 16S rRNA gene sequencing of 328 open-pollinated silk samples (healthy/Fg-infected) revealed that the TSM contains > 5000 taxa spanning the prokaryotic tree of life (47 phyla/1300 genera), including nitrogen-fixers. The TSM of silk tip tissue displayed seasonal responsiveness, but possessed a reproducible core of 7–11 MiSeq-amplicon sequence variants (ASVs) dominated by a single Pantoea MiSeq-taxon (15–26% of sequence-counts). Fg-infection collapsed TSM diversity and disturbed predicted metabolic functionality, but doubled overall microbiome size/counts, primarily by elevating 7–25 MiSeq-ASVs, suggestive of a selective microbiome response against infection. This study establishes the maize silk as a model for fundamental/applied research of plant reproductive microbiomes.

在玉米/玉米中，从玉米棒中长出的丝捕获花粉，并将驻留的精子核传递给卵子。每英亩美国玉米有 > 2000 万条蚕丝。真菌病原体使用丝通道侵入发育中的谷物，包括禾谷镰刀菌（Fg，温带环境）和破坏性致癌物生产者（非洲/热带地区）。Fg用霉菌毒素污染谷物，特别是脱氧雪腐镰刀菌烯醇 (DON)，以对人类和牲畜的健康产生不利影响而闻名。健身选择应促进防御/健康丝绸。在这里，我们报告了在其他植物中被称为风格的玉米丝，在关键的花粉 - 真菌传播间隔（以下简称：传播风格微生物组，TSM）具有复杂和动态的微生物组。在两个试验年中田间种植了不同的玉米基因型。MiSeq 16S rRNA 基因测序 328 个开放授粉蚕丝样本（健康/ Fg-infected）揭示 TSM 包含 > 5000 个跨越原核生命树（47 门/1300 属）的分类群，包括固氮菌。丝尖组织的 TSM 显示出季节性响应性，但具有由单个Pantoea MiSeq 分类单元（序列计数的 15-26% ）主导的 7-11 个 MiSeq 扩增子序列变体 (ASV) 的可重复核心。Fg感染破坏了 TSM 多样性并扰乱了预测的代谢功能，但使整体微生物组大小/计数增加了一倍，主要是通过增加 7-25 MiSeq-ASV，表明微生物组对感染的选择性反应。本研究将玉米丝建立为植物生殖微生物组基础/应用研究的模型。