Both above- and below-ground parts of plants are constantly confronted with microbes, which are main drivers for the development of plant-microbe interactions. Plant growth-promoting rhizobacteria enhance the immunity of above-ground tissues, which is known as induced systemic resistance (ISR). We show here that ISR also influences the leaf microbiome. We compared ISR triggered by the model strain Pseudomonas simiae WCS417r (WCS417) to that triggered by Bacillus thuringiensis israelensis (Bti) in Arabidopsis thaliana. In contrast to earlier findings, immunity elicited by both strains depended on salicylic acid. Both strains further relied on MYC2 for signal transduction in the plant, while WCS417-elicited ISR additionally depended on SAR-associated metabolites, including pipecolic acid. A metabarcoding approach applied to the leaf microbiome revealed a significant ISR-associated enrichment of amplicon sequence variants with predicted plant growth-promoting properties. WCS417 caused a particularly dramatic shift in the leaf microbiota with more than 50% of amplicon reads representing two bacterial species: WCS417 and Flavobacterium sp.. Co-inoculation experiments using WCS417 and At-LSPHERE Flavobacterium sp. Leaf82, suggest that the proliferation of these bacteria is influenced by both microbial and plant-derived factors. Together, our data connect systemic immunity with leaf microbiome dynamics and highlight the importance of plant-microbe-microbe interactions for plant health.

中文翻译：

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诱导的系统抗性通过植物-微生物-微生物相互作用影响叶环微生物组

植物的地上和地下部分都经常面临微生物，这是植物与微生物相互作用发展的主要驱动力。促进植物生长的根瘤菌增强了地上组织的免疫力，这被称为诱导系统抗性（ISR）。我们在这里表明，ISR也影响叶片微生物组。我们比较了拟南芥假单胞菌WCS417r（WCS417）和拟南芥苏云金芽胞杆菌以色列（Bti）触发的ISR。与先前的发现相反，两种菌株引起的免疫力都依赖于水杨酸。两种菌株在植物中都进一步依赖于MYC2进行信号转导，而WCS417引发的ISR另外还依赖于SAR相关代谢产物，包括胡椒酸。应用于叶片微生物组的元条形码方法揭示了ISR相关的扩增子序列变异体的丰富富集，并具有预测的植物生长促进特性。WCS417引起了叶片微生物群的显着变化，超过50％的扩增子读数代表两种细菌：WCS417和Flavobacterium sp.。使用WCS417和At-LSPHERE Flavobacterium sp。的共接种实验。Leaf82，表明这些细菌的增殖受到微生物和植物来源的因素的影响。总之，我们的数据将系统免疫与叶片微生物组动力学联系起来，并突出了植物-微生物-微生物相互作用对植物健康的重要性。WCS417引起了叶片微生物群的显着变化，超过50％的扩增子读数代表两种细菌：WCS417和Flavobacterium sp.。使用WCS417和At-LSPHERE Flavobacterium sp。的共接种实验。Leaf82，表明这些细菌的增殖受微生物和植物来源的因素的影响。总之，我们的数据将系统免疫与叶片微生物组动力学联系起来，并突出了植物-微生物-微生物相互作用对植物健康的重要性。WCS417引起了叶片微生物群的显着变化，超过50％的扩增子读数代表两种细菌：WCS417和Flavobacterium sp.。使用WCS417和At-LSPHERE Flavobacterium sp。的共接种实验。Leaf82，表明这些细菌的增殖受微生物和植物来源的因素的影响。总之，我们的数据将系统免疫与叶片微生物组动力学联系起来，并突出了植物-微生物-微生物相互作用对植物健康的重要性。