背景回顾+问题：Many invasive plants have enhanced mutualistic arbuscular mycorrhizal (AM) fungal associations, however, mechanisms underlying differences in AM fungal associations between introduced and native populations of invasive plants have not been explored. 

主要研究-测试假设：Here we test the hypothesis that variation in root exudate chemicals in invasive populations affects AM fungal colonization and then impacts plant performance. 

测试方法：We examined flavonoids (quercetin and quercitrin) in root exudates of native and introduced populations of the invasive plant Triadica sebifera and tested their effects on AM fungi and plant performance. 

结果1-测试结果：We found that plants from introduced populations had higher concentrations of quercetin in root exudates, greater AM fungal colonization and higher biomass.

结果2-外施根分泌物：Applying root exudates more strongly increased AM fungal colonization of target plants and AM fungal spore germination when exudate donors were from introduced populations. 

结果3-加活性炭：The role of root exudate chemicals was further confirmed by decreased AM fungal colonization when activated charcoal was added into soil. 

结果4-外施槲皮素：Moreover, addition of quercetininto soil increased AM fungal colonization, indicating quercetin might be a key chemical signal stimulating AM fungal associations.

结论：Together these results suggest genetic differences in root exudate flavonoids play an important role in enhancing AM fungal associations and invasive plants’ performance, thus considering root exudate chemicals is critical to unveiling mechanisms governing shifting plant-soil microbe interactions during plant invasions.

 摘 要 

许多入侵植物与丛枝菌根真菌具有增强的互惠关系，但是入侵植物的天然群体和引入群体之间在丛枝菌根真菌关系方面存在差异的机制还不清楚。本文中，作者测试了一个假设，即入侵群体中根系分泌物的化学物质变化影响了丛枝菌根真菌的定殖，进而影响植物的生长。作者研究了外来入侵植物乌桕（Triadica sebifera）根分泌物中的黄酮类化合物（槲皮素和槲皮苷）的含量及其对丛枝菌根真菌和植物生长的影响。作者发现，引进群体的植物根系分泌物中槲皮素的浓度较高，丛枝菌根真菌的定殖量较大，生物量也较高。外施引进群体的根系分泌物更能促进丛枝菌根真菌在目标植物上的定殖和丛枝菌根真菌孢子的萌发。当往土壤中加入活性炭时，丛枝菌根真菌的定殖量降低，进一步证明了根系分泌物中化学物质的作用。此外，往土壤中额外添加槲皮素能够增加丛枝菌根真菌的定殖，说明槲皮素可能是刺激植物与丛枝菌根真菌关系的关键化学信号物质。综上，本文的研究结果揭示了根分泌物中黄酮类化合物的遗传差异在增强丛枝菌根真菌关系和入侵植物生长方面发挥重要作用，因此根分泌物化学物质对于揭示植物入侵过程中植物与土壤微生物互作关系改变的机制至关重要。