PDF(Pubmed)
Abstract：
Plant roots secrete various metabolites, including plant specialized metabolites, into the rhizosphere, and shape the rhizosphere microbiome, which is crucial for the plant health and growth. Isoflavones are major plant specialized metabolites found in legume plants, and are involved in interactions with soil microorganisms as initiation signals in rhizobial symbiosis and as modulators of the legume root microbiota. However, it remains largely unknown the molecular basis underlying the isoflavone-mediated interkingdom interactions in the legume rhizosphere. Here, we isolated Variovorax sp. strain V35, a member of the Comamonadaceae that harbors isoflavone-degrading activity, from soybean roots and discovered a gene cluster responsible for isoflavone degradation named ifc. The characterization of ifc mutants and heterologously expressed Ifc enzymes revealed that isoflavones undergo oxidative catabolism, which is different from the reductive metabolic pathways observed in gut microbiota. We further demonstrated that the ifc genes are frequently found in bacterial strains isolated from legume plants, including mutualistic rhizobia, and contribute to the detoxification of the antibacterial activity of isoflavones. Taken together, our findings reveal an isoflavone catabolism gene cluster in the soybean root microbiota, providing molecular insights into isoflavone-mediated legume-microbiota interactions.
摘要：
植物根部分泌各种代谢物，包括植物特化代谢产物,进入根际，塑造根际微生物组，这对植物的健康和生长至关重要。异黄酮是豆科植物中发现的主要植物专门代谢产物，并参与与土壤微生物的相互作用，作为根瘤菌共生的起始信号和豆科植物根部微生物群的调节剂。然而,在豆科植物根际中，异黄酮介导的王国间相互作用的分子基础仍然未知。这里,我们分离了Variovoraxsp。菌株V35，一种具有异黄酮降解活性的Comamonadaceae成员，从大豆根中发现了一个负责异黄酮降解的基因簇，名为ifc。ifc突变体和异源表达的Ifc酶的表征表明，异黄酮经历氧化分解代谢，这与肠道微生物群中观察到的还原性代谢途径不同。我们进一步证明，ifc基因经常在豆科植物分离的细菌菌株中发现，包括相互的根瘤菌，并有助于异黄酮的抗菌活性的解毒。一起来看,我们的发现揭示了大豆根部微生物群中的异黄酮分解代谢基因簇，提供异黄酮介导的豆类-微生物群相互作用的分子见解。
