2026-05-29T22:12:56Zhttps://riuma.uma.es/rest/oai/requestoai:riuma.uma.es:10630/390072026-02-03T11:33:17Zcom_10630_2254col_10630_37953
GacA reduces virulence and increases competitiveness in planta in the tumorigenic olive pathogen Pseudomonas savastanoi pv. savastanoi
Lavado-Benito, Carla
Murillo, Jesús
Martínez Gil, Marta
Ramos-Rodríguez, Cayo Juan
Rodríguez-Moreno, Luis Gabriel
Pseudomonas syringae - Genética
Bacterias fitopatógenas
Bacterias gram negativas
The author(s) declare financial support was received for the
research, authorship, and/or publication of this article. This
research was supported by project grants PID2020-115177RB-C21
and PID2020-115177RB-C22 financed by the Spanish Ministry of
Science and Innovation (MCIN)/Agencia Estatal de Investigacioń
(AEI)/10.13039/501100011033/ and by the European Regional Development Fund (ERDF) “A way to make Europe”. CL-B was
supported by the FPI2018-084276 predoctoral grant. Open access
was partially funded by grant QUAL21 012 IHSM, Consejería de
Universidad, Investigación e Innovación, Junta de Andalucıa.
GacS/GacA is a widely distributed two-component system playing an essential
role as a key global regulator, although its characterization in phytopathogenic
bacteria has been deeply biased, being intensively studied in pathogens of
herbaceous plants but barely investigated in pathogens of woody hosts. P.
savastanoi pv. savastanoi (Psv) is characterized by inducing tumours in the
stem and branches of olive trees. In this work, the model strain Psv NCPPB
3335 and a mutant derivative with a complete deletion of gene gacA were
subjected to RNA-Seq analyses in a minimum medium and a medium mimicking
in planta conditions, accompanied by RT-qPCR analyses of selected genes and
phenotypic assays. These experiments indicated that GacA participates in the
regulation of at least 2152 genes in strain NCPPB 3335, representing 37.9 % of the
annotated CDSs. GacA also controls the expression of diverse rsm genes, and
modulates diverse phenotypes, including motility and resistance to oxidative
stresses. As occurs with other P. syringae pathovars of herbaceous plants, GacA
regulates the expression of the type III secretion system and cognate effectors. In
addition, GacA also regulates the expression of WHOP genes, specifically
encoded in P. syringe strains isolated from woody hosts, and genes for the
biosynthesis of phytohormones. A gacA mutant of NCPPB 3335 showed
increased virulence, producing large immature tumours with high bacterial
populations, but showed a significantly reduced competitiveness in planta. Our
results further extend the role of the global regulator GacA in the virulence and
fitness of a P. syringae pathogen of woody hosts
2025-06-17T08:52:55Z
2025-06-17T08:52:55Z
2024-02-05
journal article
Front. Plant Sci. 15:1347982
https://hdl.handle.net/10630/39007
10.3389/fpls.2024.1347982
eng
PID2020-115177RB-C21
PID2020-115177RB-C22
FPI2018-084276
QUAL21 012 IH
http://creativecommons.org/licenses/by/4.0/
open access
Attribution 4.0 Internacional
Frontiers Media