Colonization strategy of the endophytic plant growth-promoting strains of Pseudomonas fluorescens and Klebsiella oxytoca on the seeds, seedlings and roots of the epiphytic orchid, Dendrobium nobile Lindl.

Autor: Pavlova AS; Department of Microbiology, Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia., Leontieva MR; Department of Microbiology, Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia., Smirnova TA; Department of Cell Biology and Histology, Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia., Kolomeitseva GL; The Stock Greenhouse, Tsitsin Main Botanical Garden, Russian Academy of Sciences, Moscow, Russia., Netrusov AI; Department of Microbiology, Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia., Tsavkelova EA; Department of Microbiology, Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia.
Jazyk: angličtina
Zdroj: Journal of applied microbiology [J Appl Microbiol] 2017 Jul; Vol. 123 (1), pp. 217-232. Date of Electronic Publication: 2017 May 30.
DOI: 10.1111/jam.13481
Abstrakt: Aims: Orchids form strong mycorrhizal associations, but their interactions with bacteria are poorly understood. We aimed to investigate the distribution of plant growth promoting rhizobacteria (PGPR) at different stages of orchid development and to study if there is any selective specificity in choosing PGPR partners.
Methods and Results: Colonization patterns of gfp-tagged Pseudomonas fluorescens and Klebsiella oxytoca were studied on roots, seeds, and seedlings of Dendrobium nobile. Endophytic rhizobacteria rapidly colonized velamen and core parenchyma entering through exodermis and the passage cells, whereas at the early stages, they stayed restricted to the surface and the outer layers of the protocorms and rhizoids. The highest amounts of auxin (indole-3-acetic acid) were produced by K. oxytoca and P. fluorescens in the nitrogen-limiting and NO 3 -containing media respectively. Bacterization of D. nobile seeds resulted in promotion of their in vitro germination. The plant showed no selective specificity to the tested strains. Klebsiella oxytoca demonstrated more intense colonization activity and more efficient growth promoting impact under tryptophan supplementation, while P. fluorescens revealed its growth-promoting capacity without tryptophan.
Conclusions: Both strategies are regarded as complementary, improving adaptive potentials of the orchid when different microbial populations colonize the plant.
Significance and Impact of the Study: This study enlarges our knowledge on orchid-microbial interactions, and provides new features on application of the nonorchid PGPR in orchid seed germination and conservation.
(© 2017 The Society for Applied Microbiology.)
Databáze: MEDLINE
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