Rosier Amanda, Beauregard Pascale B, Bais Harsh P
Department of Plant and Soil Sciences, University of Delaware, Newark, DE, United States.
Delaware Biotechnology Institute, University of Delaware, Newark, DE, United States.
Front Microbiol. 2021 Jan 15;11:596299. doi: 10.3389/fmicb.2020.596299. eCollection 2020.
Plant growth-promoting rhizobacteria (PGPR) have enormous potential for solving some of the myriad challenges facing our global agricultural system. Intense research efforts are rapidly moving the field forward and illuminating the wide diversity of bacteria and their plant beneficial activities. In the development of better crop solutions using these PGPR, producers are including multiple different species of PGPR in their formulations in a "consortia" approach. While the intention is to emulate more natural rhizomicrobiome systems, the aspect of bacterial interactions has not been properly regarded. By using a tri-trophic model of A17 Jemalong, its nitrogen (N)-fixing symbiont Rm8530, and the PGPR UD1022, we demonstrate indirect influences between the bacteria affecting their plant growth-promoting activities. Co-cultures of UD1022 with Rm8530 significantly reduced Rm8530 biofilm formation and downregulated quorum sensing (QS) genes responsible for symbiotically active biofilm production. This work also identifies the presence and activity of a quorum quenching lactonase in UD1022 and proposes this as the mechanism for non-synergistic activity of this model "consortium." These interspecies interactions may be common in the rhizosphere and are critical to understand as we seek to develop new sustainable solutions in agriculture.
植物促生根际细菌（PGPR）在应对全球农业系统面临的众多挑战方面具有巨大潜力。大量的研究工作正在迅速推动该领域向前发展，并揭示了细菌的广泛多样性及其对植物有益的活动。在利用这些PGPR开发更好的作物解决方案时，生产者采用“联合体”方法，在其配方中纳入多种不同的PGPR物种。虽然目的是模仿更自然的根际微生物组系统，但细菌相互作用的方面尚未得到适当考虑。通过使用A17杰马朗（A17 Jemalong）、其固氮共生体Rm8530和PGPR UD1022的三营养模型，我们证明了细菌之间的间接影响会影响它们促进植物生长的活动。UD1022与Rm8530的共培养显著减少了Rm8530生物膜的形成，并下调了负责共生活性生物膜产生的群体感应（QS）基因。这项工作还确定了UD1022中群体淬灭内酯酶的存在和活性，并提出这是该模型“联合体”非协同活性的机制。这些种间相互作用在根际可能很常见，在我们寻求开发新的农业可持续解决方案时，了解这些相互作用至关重要。
