Constantin Maria E, Vlieger Babette V, Takken Frank L W, Rep Martijn
Molecular Plant Pathology, Faculty of Science, Swammerdam Institute for Life Sciences, University of Amsterdam, 1098 XH Amsterdam, The Netherlands.
Microorganisms. 2020 Apr 9;8(4):544. doi: 10.3390/microorganisms8040544.
Root colonization by (Fo) endophytes reduces wilt disease symptoms caused by pathogenic Fo strains. The endophytic strain Fo47, isolated from wilt suppressive soils, reduces wilt in various crop species such as tomato, flax, and asparagus. How endophyte-mediated resistance (EMR) against wilt is achieved is unclear. Here, nonpathogenic colonization by Fo47 and pathogenic colonization by Fo f.sp. (Fol) strains were assessed in tomato roots and stems when inoculated separately or coinoculated. It is shown that Fo47 reduces Fol colonization in stems of both noncultivated and cultivated tomato species. Conversely, Fo47 colonization of coinoculated tomato stems was increased compared to single inoculated plants. Quantitative PCR of fungal colonization of roots (co)inoculated with Fo47 and/or Fol showed that pathogen colonization was drastically reduced when coinoculated with Fo47, compared with single inoculated roots. Endophytic colonization of tomato roots remained unchanged upon coinoculation with Fol. In conclusion, EMR against wilt is correlated with a reduction of root and stem colonization by the pathogen. In addition, the endophyte may take advantage of the pathogen-induced suppression of plant defences as it colonizes tomato stems more extensively.
尖孢镰刀菌（Fo）内生菌在根部的定殖可减轻由致病性尖孢镰刀菌菌株引起的枯萎病症状。从枯萎病抑制性土壤中分离出的内生菌株Fo47可减轻多种作物（如番茄、亚麻和芦笋）的枯萎病。目前尚不清楚内生菌介导的对枯萎病的抗性（EMR）是如何实现的。在此，分别接种或共接种时，评估了番茄根和茎中Fo47的非致病性定殖以及尖孢镰刀菌枯萎专化型（Fol）菌株的致病性定殖情况。结果表明，Fo47可减少野生型和栽培型番茄品种茎中Fol的定殖。相反，与单接种植株相比，共接种番茄茎中Fo47的定殖增加。对用Fo47和/或Fol（共）接种的根进行真菌定殖的定量PCR分析表明，与单接种根相比，与Fo47共接种时病原菌定殖大幅减少。与Fol共接种后，番茄根的内生定殖保持不变。总之，对枯萎病的EMR与病原菌在根和茎中的定殖减少相关。此外，内生菌在更广泛地定殖番茄茎时，可能利用了病原菌诱导的植物防御抑制作用。
