Response to fungal exudates of the rhizosphere isolate Pseudomonas sp. UMAF110 involves a GGDEF/EAL domain-containing protein
Pintado Calvillo, Adrián,Aragón Cortés, Isabel María,Pérez-Martínez, Isabel,Pliego-Prieto, Clara,Crespo-Gómez, José Ignacio,De-Vicente-Moreno, Antonio,Cazorla-López, Francisco Manuel,Ramos-Rodríguez, Cayo Juan
- Published
- 2017-09-02
- Language
- sp
Abstract
Pseudomonas sp. UMAF110, isolated from rhizosphere soil in Spain, display in vitro antagonism towards the pythopathogenic fungus Rosellinia necatrix and is able grow in fungal exudates (BM-RE medium). A transposon mutant library of this strain was constructed and several mutants were selected by their reduced competitiveness in BM-RE medium. Pseudomonas sp. UMAF110-G3, which contains the transposon into a gene encoding a putative REC/PAS/GGDEF/EAL protein, was selected for further characterization. Blastn searches using the sequence of the gene interrupted by the transposon in UMAF110-G3, here called cmpA (c-di-GMP Metabolizing Protein), yielded a single positive hit (98% cover, 78% identity) with a gene from a terpene-degrading Pseudomonas sp. strain isolated from soil. Context analysis of the cmpA gene in Pseudomonas sp. UMAF110 showed that this gene is located downstream from several genes involved in flagellar motility/chemotaxis. RT-PCR experiments further confirmed that cmpA form a transcriptional unit with the che gene cluster. Expression analysis of cmpA by qRT-PCR clearly showed upregulation of this gene after transfer of Pseudomonas sp. UMAF110 cells to BM-RE medium, suggesting a role for this operon in response to fungal exudates. Deletion of cmpA in Pseudomonas sp. UMAF110 did not affect the ability of the strain to form biofilms under the conditions tested. However, overexpression of wild type CmpA in Pseudomonas putida KT2440 negatively regulated biofilm formation in this strain. Together, these results suggest that CmpA could be involved in signal transduction pathways regulating flagellar motility/chemotaxis in response to fungal exudates.
Full text
170 | Please note: Abstracts are published as received from the authors and are not subject to editing Infections & Host-Pathogen Interactions P169 Response to fungal exudates of the rhizosphere isolate Pseudomonas sp. UMAF110 involves a GGDEF/EAL domain-containing protein. Adrian Pintado1, Isabel M. Aragon1, Isabel Perez-Martinez1, Clara Pliego2, J. Ignacio CrespoGomez1 ,3, Antonio de Vicente3, Francisco M. Cazorla3, Cayo Ramos1 1Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora”, Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Área de Genética, Universidad de Málaga, Malaga, Spain, 2IFAPA, Centro de Churriana (CICE Junta de Andalucía), Malaga, Spain, 3Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora”, Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSMUMA-CSIC), Departamento de Microbiología, Universidad, Malaga, Spain Pseudomonas sp. UMAF110, isolated from rhizosphere soil in Spain, display in vitro antagonism towards the pythopathogenic fungus Rosellinia necatrix and is able grow in fungal exudates (BM-RE medium). A transposon mutant library of this strain was constructed and several mutants were selected by their reduced competitiveness in BM-RE medium. Pseudomonas sp. UMAF110-G3, which contains the transposon into a gene encoding a putative REC/PAS/GGDEF/EAL protein, was selected for further characterization. Blastn searches using the sequence of the gene interrupted by the transposon in UMAF110G3, here called cmpA (c-di-GMP Metabolizing Protein), yielded a single positive hit (98% cover, 78% identity) with a gene from a terpene-degrading Pseudomonas sp. strain isolated from soil. Context analysis of the cmpA gene in Pseudomonas sp. UMAF110 showed that this gene is located downstream from several genes involved in flagellar motility/chemotaxis. RT-PCR experiments further confirmed that cmpA form a transcriptional unit with the che gene cluster. Expression analysis of cmpA by qRT-PCR clearly showed upregulation of this gene after transfer of Pseudomonas sp. UMAF110 cells to BM-RE medium, suggesting a role for this operon in response to fungal exudates. Deletion of cmpA in Pseudomonas sp. UMAF110 did not affect the ability of the strain to form biofilms under the conditions tested. However, overexpression of wild type CmpA in Pseudomonas putida KT2440 negatively regulated biofilm formation in this strain. Together, these results suggest that CmpA could be involved in signal transduction pathways regulating flagellar motility/chemotaxis in response to fungal exudates.
