Wei Zhong, Yang Tianjie, Friman Ville-Petri, Xu Yangchun, Shen Qirong, Jousset Alexandre
Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic-based Fertilizers, Nanjing Agricultural University, Weigang 1, Nanjing 210095, China.
Imperial College London, Silwood Park Campus, Buckhurst Road, Ascot, Berkshire SL5 7PY, UK.
Nat Commun. 2015 Sep 24;6:8413. doi: 10.1038/ncomms9413.
Host-associated bacterial communities can function as an important line of defence against pathogens in animals and plants. Empirical evidence and theoretical predictions suggest that species-rich communities are more resistant to pathogen invasions. Yet, the underlying mechanisms are unclear. Here, we experimentally test how the underlying resource competition networks of resident bacterial communities affect invasion resistance to the plant pathogen Ralstonia solanacearum in microcosms and in tomato plant rhizosphere. We find that bipartite resource competition networks are better predictors of invasion resistance compared with resident community diversity. Specifically, communities with a combination of stabilizing configurations (low nestedness and high connectance), and a clear niche overlap with the pathogen, reduce pathogen invasion success, constrain pathogen growth within invaded communities and have lower levels of diseased plants in greenhouse experiments. Bacterial resource competition network characteristics can thus be important in explaining positive diversity-invasion resistance relationships in bacterial rhizosphere communities.
与宿主相关的细菌群落可作为动植物抵御病原体的重要防线。经验证据和理论预测表明，物种丰富的群落对病原体入侵更具抵抗力。然而，其潜在机制尚不清楚。在此，我们通过实验测试了常驻细菌群落的潜在资源竞争网络如何影响微观世界和番茄根际对植物病原体青枯雷尔氏菌的入侵抗性。我们发现，与常驻群落多样性相比，二分资源竞争网络是入侵抗性更好的预测指标。具体而言，具有稳定构型组合（低嵌套性和高连通性）且与病原体有明显生态位重叠的群落，会降低病原体入侵成功率，限制病原体在入侵群落中的生长，并且在温室实验中病株水平较低。因此，细菌资源竞争网络特征对于解释细菌根际群落中多样性与入侵抗性的正相关关系可能很重要。
