Data_Sheet_1_Enhanced Yield of Pepper Plants Promoted by Soil Application of Volatiles From Cell-Free Fungal Culture Filtrates Is Associated With Activation of the Beneficial Soil Microbiota.zip

Plants communicate with microorganisms by exchanging chemical signals throughout the phytosphere. Such interactions are important not only for plant productivity and fitness, but also for terrestrial ecosystem functioning. It is known that beneficial microorganisms emit diffusible substances including volatile organic compounds (VOCs) that promote growth. Consistently, soil application of cell-free culture filtrates (CF) of beneficial soil and plant-associated microorganisms enhances plant growth and yield. However, how this treatment acts in plants and whether it alters the resident soil microbiota, are largely unknown. In this work we characterized the responses of pepper (Capsicum annuum L.) plants cultured under both greenhouse and open field conditions and of soil microbiota to soil application of CFs of beneficial and phytopathogenic fungi. To evaluate the contribution of VOCs occurring in the CFs to these responses, we characterized the responses of plants and of soil microbiota to application of distillates (DE) of the fungal CFs. CFs and their respective DEs contained the same potentially biogenic VOCs, and application of these extracts enhanced root growth and fruit yield, and altered the nutritional characteristics of fruits. High-throughput amplicon sequencing of bacterial 16S and fungal ITS rRNA genes of the soil microbiota revealed that the CF and DE treatments altered the microbial community compositions, and led to strong enrichment of the populations of the same beneficial bacterial and fungal taxa. Our findings show that CFs of both beneficial and phytopathogenic fungi can be used as biostimulants, and provide evidence that VOCs occurring in the fungal CFs act as mediators of the plants’ responses to soil application of fungal CFs through stimulation of the beneficial soil microbiota.

植物可通过植物圈（phytosphere）内的化学信号交换，与微生物开展交流。此类互作不仅关乎植物的生产力与生存适合度，更对陆地生态系统的功能运行具有重要意义。已有研究表明，有益微生物可释放包括挥发性有机化合物（VOCs）在内的扩散性物质，进而促进植物生长。与之相符的是，向土壤施加有益土壤及植物相关微生物的无细胞培养滤液（CF），能够提升植物的生长态势与产量水平。然而，这类处理如何作用于植物，以及其是否会改变原位土壤微生物群，目前尚不明晰。本研究中，我们针对温室与大田栽培条件下的辣椒（Capsicum annuum L.）植株，以及土壤微生物群对有益真菌与植物病原真菌无细胞培养滤液（CF）土壤施用的响应展开了表征分析。为明确CF中所含VOCs在上述响应中的贡献，我们进一步表征了植株与土壤微生物群对真菌CF蒸馏馏分（DE）施用的响应。实验结果显示，CF及其对应的DE含有相同的潜在生物源性VOCs，施用这类提取物可促进根系生长、提升果实产量，并改变果实的营养特性。通过对土壤微生物群的细菌16S与真菌ITS核糖体RNA（rRNA）基因开展高通量扩增子测序，我们发现CF与DE处理均改变了微生物群落组成，并显著富集了相同的有益细菌与真菌类群。本研究结果表明，无论是有益真菌还是植物病原真菌的无细胞培养滤液，均可作为生物刺激剂使用；同时证实真菌CF中的VOCs可通过刺激有益土壤微生物群，介导植株对真菌CF土壤施用的响应。