Signs of a phyllospheric lifestyle in the genome of the stress-tolerant strain Azospirillum brasilense Az19.

Autor: García JE; Instituto Nacional de Tecnología Agropecuaria (INTA), Instituto de Microbiología y Zoología Agrícola, Nicolas Repetto and de los Reseros, Hurlingham B1686, Buenos Aires, Argentina., Labarthe MM; Facultad de Ciencias Agrarias, Universidad Nacional de Mar del Plata, km 73.5 226 route, Balcarce B7620, Buenos Aires, Argentina., Pagnussat LA; Facultad de Ciencias Agrarias, Universidad Nacional de Mar del Plata, km 73.5 226 route, Balcarce B7620, Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas, 2290 Godoy Cruz str., CABA C1425FQB, Argentina., Amenta M; Facultad de Ciencias Agrarias, Universidad Nacional de Mar del Plata, km 73.5 226 route, Balcarce B7620, Buenos Aires, Argentina., Creus CM; Facultad de Ciencias Agrarias, Universidad Nacional de Mar del Plata, km 73.5 226 route, Balcarce B7620, Buenos Aires, Argentina., Maroniche GA; Facultad de Ciencias Agrarias, Universidad Nacional de Mar del Plata, km 73.5 226 route, Balcarce B7620, Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas, 2290 Godoy Cruz str., CABA C1425FQB, Argentina. Electronic address: gmaroniche@mdp.edu.ar.
Jazyk: angličtina
Zdroj: Systematic and applied microbiology [Syst Appl Microbiol] 2020 Nov; Vol. 43 (6), pp. 126130. Date of Electronic Publication: 2020 Aug 19.
DOI: 10.1016/j.syapm.2020.126130
Abstrakt: Azospirillum brasilense Az19 is a plant-beneficial bacterium capable of protecting plants from the negative effects of drought. The objective of this study was to determine and analyze the genomic sequence of strain Az19 as a means of identifying putative stress-adaptation mechanisms. A high-quality draft genome of ca. 7 Mb with a predicted coding potential of 6710 genes was obtained. Phylogenomic analyses confirmed that Az19 belongs to the brasilense clade and is closely related to strains Az39 and REC3. Functional genomics revealed that the denitrification pathway of Az19 is incomplete, which was in agreement with a reduced growth on nitrate under low O 2 concentrations. Putative genes of the general stress response and oxidative stress-tolerance, as well as synthesis of exopolysaccharides, carotenoids, polyamines and several osmolytes, were detected. An additional poly-beta-hydroxybutyrate (PHB) synthase coding gene was found in Az19 genome, but the accumulation of PHB did not increase under salinity. The detection of exclusive genes related to DNA repair led to discover that strain Az19 also has improved UV-tolerance, both in vitro and in planta. Finally, the analysis revealed the presence of multiple kaiC-like genes, which could be involved in stress-tolerance and, possibly, light responsiveness. Although A. brasilense has been a model for the study of beneficial plant-associated rhizobacteria, the evidence collected in this current study suggests, for the first time in this bacterial group, an unexpected possibility of adaptation to the phyllosphere.
Competing Interests: Declaration of Competing Interest The authors report no declarations of interest.
(Copyright © 2020 Elsevier GmbH. All rights reserved.)
Databáze: MEDLINE
Externí odkaz: