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Friend or foe: genetic and functional characterization of plant endophytic P seudomonas aeruginosa
Author(s) -
Kumar A.,
Munder A.,
Aravind R.,
Eapen S. J.,
Tümmler B.,
Raaijmakers J. M.
Publication year - 2013
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/1462-2920.12031
Subject(s) - biology , phytophthora capsici , multilocus sequence typing , pseudomonas aeruginosa , oomycete , microbiology and biotechnology , virulence , pepper , radopholus similis , phytophthora , botany , pathogen , bacteria , genotype , genetics , gene , horticulture , nematode , ecology
Summary Endophytic P seudomonas aeruginosa strain BP 35 was originally isolated from black pepper grown in the rain forest in K erala, I ndia. Strain PaBP 35 was shown to provide significant protection to black pepper against infections by P hytophthora capsici and R adopholus similis . For registration and implementation in disease management programmes, several traits of PaBP 35 were investigated including its endophytic behaviour, biocontrol activity, phylogeny and toxicity to mammals. The results showed that PaBP 35 efficiently colonized black pepper shoots and displayed a typical spatiotemporal pattern in its endophytic movement with concomitant suppression of P hytophthora rot. Confocal laser scanning microscopy revealed high populations of PaBP 35:: gfp2 inside tomato plantlets, supporting its endophytic behaviour in other plant species. Polyphasic approaches to genotype PaBP 35, including BOX‐PCR , rec N sequence analysis, multilocus sequence typing and comparative genome hybridization analysis, revealed its uniqueness among P . aeruginosa strains representing clinical habitats. However, like other P . aeruginosa strains, PaBP 35 exhibited resistance to antibiotics, grew at 25–41° C and produced rhamnolipids and phenazines. PaBP 35 displayed strong type II secretion effectors‐mediated cytotoxicity on mammalian A 549 cells. Coupled with pathogenicity in a murine airway infection model, we conclude that this plant endophytic strain is as virulent as clinical P . aeruginosa strains. Safety issues related to the selection of plant endophytic bacteria for crop protection are discussed.