State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, Henan, China.
Key Lab Aquatic Botany & Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, Hubei, China.
ISME J. 2021 Jul;15(7):1919-1930. doi: 10.1038/s41396-021-00894-1. Epub 2021 Feb 10.
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. Here we test the hypothesis that variation in root exudate chemicals in invasive populations affects AM fungal colonization and then impacts plant performance. 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. We found that plants from introduced populations had higher concentrations of quercetin in root exudates, greater AM fungal colonization and higher biomass. Applying root exudates more strongly increased AM fungal colonization of target plants and AM fungal spore germination when exudate donors were from introduced populations. The role of root exudate chemicals was further confirmed by decreased AM fungal colonization when activated charcoal was added into soil. Moreover, addition of quercetin into soil increased AM fungal colonization, indicating quercetin might be a key chemical signal stimulating AM fungal associations. 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.
许多入侵植物与互惠共生的丛枝菌根（AM）真菌有更强的联系，然而，引入和本地入侵植物种群之间 AM 真菌联系的差异的机制尚未被探索。在这里，我们检验了以下假设，即入侵种群的根系分泌物化学物质的变化会影响 AM 真菌的定殖，从而影响植物的表现。我们研究了入侵植物三叶鬼针草的本地和引入种群的根系分泌物中的类黄酮（槲皮素和槲皮苷），并测试了它们对 AM 真菌和植物性能的影响。我们发现，来自引入种群的植物在根系分泌物中有更高浓度的槲皮素，具有更高的 AM 真菌定殖和更高的生物量。当供体来自引入种群时，根系分泌物更强烈地增加了目标植物的 AM 真菌定殖和 AM 真菌孢子萌发。当向土壤中添加活性炭时，AM 真菌定殖减少，进一步证实了根系分泌物化学物质的作用。此外，向土壤中添加槲皮素增加了 AM 真菌的定殖，表明槲皮素可能是刺激 AM 真菌联系的关键化学信号。这些结果表明，根系分泌物中类黄酮的遗传差异在增强 AM 真菌联系和入侵植物的表现方面起着重要作用，因此考虑根系分泌物化学物质对于揭示植物入侵过程中植物-土壤-微生物相互作用的变化机制至关重要。
