论文题目：Volatile-mediated microbiome enrichment by Streptomyces albidoflavus G1 enhances suppression of apple ring rot pathogen Botryosphaeria dothidea
论文作者：Shengzhi Guo#, Arneeb Tariq#, Yarong Luo, Xianyu Li, Zixu Wang, Zhinan Du, Qi Cheng, Jiangbo Qi, Junfeng Pan, Lingfang Zhu*, Xihui Shen*
论文摘要：Apple ring rot, caused by the fungal pathogen Botryosphaeria dothidea, is a devastating disease that causes substantial production and postharvest losses worldwide. Microbial volatile organic compounds (VOCs) are promising biocontrol agents against postharvest fungal diseases. However, how VOCs produced by Streptomyces albidoflavus suppress B. dothidea and whether they are associated with changes in the apple microbiota and the host transcriptional response remains largely unexplored.This study integrated volatilome profiling, microbiome analysis, VOC-bacterial interaction assays, and apple transcriptome profiling to investigate how G1-VOCs suppress apple ring rot. G1 showed strong VOC-mediated inhibitory activity against B. dothidea in bipartite plate and detached fruit assays. GC–MS analysis identified differentially abundant volatiles associated with sesquiterpenoid, triterpenoid, and phenylalanine metabolism, and selected VOC standards impaired fungal growth, membrane integrity, and biofilm formation under the tested assay conditions. 16S rRNA gene amplicon analysis revealed that G1-VOC exposure under pathogen challenge was associated with a simplified, Pseudomonas-dominated bacterial community in internal lesion-margin tissues, accompanied by increased Pseudomonas-specific 16S rRNA gene copies. The cultivable isolate Pseudomonas paracarnis aNRL1, recovered from G1-VOC-treated lesion-margin tissues, matched the enriched Pseudomonas-assigned ASV_2, strongly inhibited B. dothidea in vitro, and reduced lesion development on apple fruit. Selected G1-associated volatiles exerted compound-specific effects on aNRL1 growth, biofilm formation and motility. Apple transcriptome analysis further revealed pathogen-dependent remodeling of brassinosteroid signaling, together with increased expression of genes related to mitogen-activated protein kinase (MAPK), lipid metabolism, and cuticle/wax biosynthesis. Together, these findings support a multilayered model in which G1-derived VOCs directly impair B. dothidea physiology while coinciding with Pseudomonas-dominated restructuring of the internal lesion-margin bacterial community and host barrier- and defense-associated transcriptional remodeling, with P. paracarnis aNRL1 providing a cultivable functional link to the enriched Pseudomonas signal.
苹果轮纹病由真菌病原菌葡萄座腔菌引起，危害严重，在全球范围内造成大量生产及采后损失。微生物挥发性有机化合物在采后真菌病害的生物防治中具有应用潜力。然而，白黄链霉菌产生的VOCs如何抑制葡萄座腔菌，以及其是否与苹果微生物群和宿主转录响应的变化相关，仍有待深入研究。本研究整合挥发性代谢组分析、微生物组分析、VOCs与细菌互作试验及苹果转录组分析，探究G1产生的VOCs（G1-VOCs）抑制苹果轮纹病的作用机制。在分隔平板和离体果实试验中，G1均表现出较强的VOCs介导的葡萄座腔菌抑制活性。气相色谱–质谱联用（GC–MS）分析鉴定出与倍半萜类、三萜类及苯丙氨酸代谢相关的差异挥发性物质；在所测试的试验条件下，所选VOCs标准品能够抑制真菌生长、破坏细胞膜完整性并抑制生物膜形成。16S rRNA基因扩增子分析表明，在病原菌侵染条件下，G1-VOCs处理与病斑边缘内部组织中细菌群落向结构简化、假单胞菌属占优势的状态转变相关，同时伴随假单胞菌属特异性16S rRNA基因拷贝数增加。从G1-VOCs处理的病斑边缘组织中分离获得的可培养菌株 Pseudomonas paracarnis aNRL1，与富集的假单胞菌属ASV_2相匹配，在体外对葡萄座腔菌具有较强的抑制活性，并能抑制苹果果实病斑的发展。所选G1相关挥发性物质对aNRL1生长、生物膜形成和运动性的影响因化合物而异。苹果转录组分析进一步显示，油菜素内酯信号传导呈现病原菌依赖性重塑，同时丝裂原活化蛋白激酶、脂质代谢及角质层/蜡质生物合成相关基因的表达上调。上述结果支持一个多层次的作用模型：G1来源的VOCs直接干扰葡萄座腔菌的生理功能，同时伴随病斑边缘内部细菌群落向假单胞菌属占优势的结构重组，以及宿主屏障与防御相关的转录重塑。其中，P. paracarnis aNRL1将富集的假单胞菌属信号与可培养菌株的抑病功能联系起来。
论文链接：https://doi.org/10.1186/s40168-026-02540-4