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Antagonistic effects of Pseudomonas jessenii against Pythium aphanidermatum : morphological, ultrastructural and cytochemical aspects
Author(s) -
Deora Abhinandan,
Hashidoko Yasuyuki,
Tahara Satoshi
Publication year - 2008
Publication title -
journal of basic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.58
H-Index - 54
eISSN - 1521-4028
pISSN - 0233-111X
DOI - 10.1002/jobm.200700350
Subject(s) - pythium aphanidermatum , biology , hypha , vacuole , microbiology and biotechnology , ultrastructure , cytoskeleton , phalloidin , population , actin , cytoplasm , cell , biochemistry , botany , demography , biological pest control , sociology
Pseudomonas jessenii isolate EC‐S101, an antagonistic rhizobacterium, induces morphological abnormalities such as topical swelling and excessive lateral branching in phytopathogenic Peronosporomycetes Pythium aphanidermatum hyphae as a result of radial growth inhibition in a dual culture assay. Rhodamine‐phalloidin staining revealed that these abnormalities were associated with disorganization of actin cytoskeleton. Both the morphological forms of actin, filaments and plaques, were affected progressively. At early stage of interaction (in less affected hyphae), the filaments were either eliminated or disarrayed. At advance stage of interaction (in severely affected hyphae), even the plaques population was decreased or disappeared. The effects of P . jessenii on actin architecture of Py . aphanidermatum were comparable to latrunculin B, a known actin assembly inhibitor. In addition, at early stage of interaction, the quantities of nuclei, lipid bodies and mitochondria became higher than those in control. At advance stage of interaction, the quantities of these organelles were almost similar, higher and lower, respectively, compare to those in control. Scanning electron microscopy exhibited cell wall disruption and accumulation of extracellular material associated with severely affected hyphae. Ultrastructural observations of the affected hyphae displayed additional features of considerable thickening of cell wall, enlargement of vacuoles, sinking of redundant lipid bodies into the enlarged vacuoles and wall appositions. We conclude that in addition to interference in morphogenesis and growth of Py . aphanidermatum , P . jessenii suppresses the pathogen through sub‐cellular disorganization, specifically the actin architecture. This is the first report on disruption of cytoskeleton in a eukaryotic phytopathogen by an antagonistic rhizobacterium. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)