Bassani Ilaria, Rancurel Corinne, Pagnotta Sophie, Orange François, Pons Nicolas, Lebrigand Kevin, Panabières Franck, Counillon Laurent, Noblin Xavier, Galiana Eric
Université Côte d'Azur, INRAE, CNRS, ISA, 06903 Sophia Antipolis, France.
Université Côte d'Azur, Centre Commun de Microscopie Appliquée, 06108 Nice, France.
Microorganisms. 2020 Jul 7;8(7):1012. doi: 10.3390/microorganisms8071012.
Most pathogenic oomycetes of the genus spread in water films as flagellated zoospores. Zoospores perceive and produce signals attracting other zoospores, resulting in autoaggregation in vitro or biofilm formation on plant surface. The mechanisms underlying intercellular communication and consequent attraction, adhesion and aggregation are largely unknown. In the perception of a K gradient induces coordinated motion and aggregation. To define cellular and molecular events associated with oomycete aggregation, we combined transcriptomic and ultrastructural analyses. Results indicate involvement of electroception in K sensing. They establish that the transcriptome repertoire required for swimming and aggregation is already fully functional at zoospore release. At the time points analyzed, aggregates are mainly constituted of zoospores. They produce vesicular and fibrillary material discharged at cell-to-cell contacts. Consistently, the signature of transcriptome dynamics during transition to aggregates is an upregulation of genes potentially related to vesicular trafficking. Moreover, transcriptomic and functional analyses show a strong enhancement of carbonic anhydrase activity, indicating that pH homeostasis may contribute to aggregation by acting on both zoospore movement and adhesion. This study poses the molecular and cellular bases of aggregative behavior within oomycetes and expands the current knowledge of ion perception-mediated dissemination of propagules in the rhizosphere.
该属的大多数致病卵菌以具鞭毛的游动孢子在水膜中传播。游动孢子感知并产生吸引其他游动孢子的信号，导致体外自动聚集或在植物表面形成生物膜。细胞间通讯以及随之而来的吸引、黏附和聚集的潜在机制在很大程度上尚不清楚。在[具体物种]中，对钾离子梯度的感知会诱导协调运动和聚集。为了确定与卵菌聚集相关的细胞和分子事件，我们结合了转录组学和超微结构分析。结果表明电感受参与了钾离子感知。研究确定，游动和聚集所需的转录组在游动孢子释放时就已完全发挥功能。在所分析的时间点，聚集体主要由游动孢子组成。它们产生在细胞间接触时释放的囊泡状和纤维状物质。一致的是，向聚集体转变过程中转录组动态变化的特征是与囊泡运输潜在相关基因的上调。此外，转录组学和功能分析表明碳酸酐酶活性显著增强，这表明pH稳态可能通过作用于游动孢子的运动和黏附来促进聚集。这项研究奠定了卵菌聚集行为的分子和细胞基础，并扩展了目前关于离子感知介导的繁殖体在根际传播的知识。
