Institut d'Ecologie et des Sciences de l'Environnement (CNRS-UPMC-IRD-UPEC-Univ.Paris-Diderot), Université Paris-Est Créteil, 60 Avenue du Général de Gaulle, 94010 Créteil Cedex, France.
Institut d'Ecologie et des Sciences de l'Environnement (CNRS-UPMC-IRD-UPEC-Univ.Paris-Diderot), Université Paris-Est Créteil, 60 Avenue du Général de Gaulle, 94010 Créteil Cedex, France.
Environ Pollut. 2018 Nov;242(Pt A):113-125. doi: 10.1016/j.envpol.2018.06.073. Epub 2018 Jun 26.
Tropospheric ozone (O) concentrations have now reached levels that can potentially affect crop production in several regions of the world. The interacting effects of the elevated O and temperature on plants are still unclear and their consequences on the rhizosphere microbial communities never studied yet. Here, we conducted a 3-week fumigation experiment on two cultivars of wheat with different tolerance to O (Premio and Soissons) at two temperatures (20 °C and 30 °C). The impacts of O were measured on plants physiology, rhizosphere chemical environment and microbial communities. Globally, most of the results showed that elevated O effects were more pronounced at 20 °C than 30 °C, especially on the most Osensitive cultivar (Soissons). Elevated O reduced significantly plant root biomass (up to -37% for Soissons) compared to non-fumigated plants. A decrease in the dissolved organic matter with a relative increase of aromatic compounds concentration was also observed under elevated O, suggesting quantitative and qualitative impacts on roots exudation. While bacterial abundance was negatively affected by O plant stress, fungal abundance was found to be stimulated (up to 12 fold compared to non-fumigated plants for Soissons at 20 °C). These changes were accompanied by modifications of the genetic structures and metabolic profiles, with a relative increase of amino acids catabolism. This fully controlled laboratory experiment showed that the effects of elevated O on soil microbial communities i) are plant-mediated and depend on the cultivar sensitivity, ii) decrease in warming condition, iii) increase the fungi to bacteria ratio and iv) alter both the genetic structure and the metabolic activities. This study highlights the importance of considering interactive effects between pollutants and climate changes on plant-microbe relationship to better inform models and improve predictions of future states of agroecosystems.
对流层臭氧 (O) 浓度现已达到可能影响世界多个地区作物生产的水平。升高的 O 和温度对植物的相互作用影响尚不清楚，它们对根际微生物群落的影响尚未研究。在这里，我们在两个不同 O 耐受性的小麦品种（Premio 和 Soissons）上进行了为期 3 周的熏气实验，温度为 20°C 和 30°C。测量了 O 对植物生理学、根际化学环境和微生物群落的影响。总的来说，大多数结果表明，升高的 O 在 20°C 时比在 30°C 时更为明显，尤其是对最敏感的品种（Soissons）。与未熏气的植物相比，升高的 O 显著降低了植物根生物量（Soissons 可达 -37%）。还观察到在升高的 O 下，溶解有机物减少，芳香族化合物浓度相对增加，这表明对根分泌有定量和定性的影响。虽然 O 对植物胁迫会降低细菌丰度，但发现真菌丰度受到刺激（与未熏气的植物相比，Soissons 在 20°C 时增加了 12 倍）。这些变化伴随着遗传结构和代谢谱的改变，氨基酸分解代谢相对增加。这个完全受控的实验室实验表明，升高的 O 对土壤微生物群落的影响 i）是植物介导的，并取决于品种的敏感性，ii）在变暖条件下减少，iii）增加真菌与细菌的比例，iv）改变遗传结构和代谢活性。这项研究强调了考虑污染物和气候变化之间的交互作用对植物-微生物关系的重要性，以更好地为模型提供信息并改善对未来农业生态系统状态的预测。
