Endophytic Methylobacterium extorquens expresses a heterologous β-1,4-endoglucanase A (EglA) in Catharanthus roseus seedlings, a model host plant for Xylella fastidiosa.
Based on the premise of symbiotic control, we genetically modified the citrus endophytic bacterium Methylobacterium extorquens, strain AR1.6/2, and evaluated its capacity to colonize a model plant and its interaction with Xylella fastidiosa, the causative agent of Citrus Variegated Chlorosis (CVC). AR1.6/2 was genetically transformed to express heterologous GFP (Green Fluorescent Protein) and an endoglucanase A (EglA), generating the strains ARGFP and AREglA, respectively. By fluorescence microscopy, it was shown that ARGFP was able to colonize xylem vessels of the Catharanthus roseus seedlings. Using scanning electron microscopy, it was observed that AREglA and X. fastidiosa may co-inhabit the C. roseus vessels. M. extorquens was observed in the xylem with the phytopathogen X. fastidiosa, and appeared to cause a decrease in biofilm formation. AREglA stimulated the production of resistance protein, catalase, in the inoculated plants. This paper reports the successful transformation of AR1.6/2 to generate two different strains with a different gene each, and also indicates that AREglA and X. fastidiosa could interact inside the host plant, suggesting a possible strategy for the symbiotic control of CVC disease. Our results provide an enhanced understanding of the M. extorquens-X. fastidiosa interaction, suggesting the application of AR1.6/2 as an agent of symbiotic control.
Department of Phytopathology, University of Passo Fundo (UPF), BR 285, PO BOX 611, Passo Fundo, RS, 99052-900, Brazil.
Antônio Sérgio
AS
Ferreira Filho
Maria Carolina
MC
Quecine
Andréa Cristina
AC
Bogas
Priscilla de Barros
Pde B
Rossetto
Andre Oliveira de Souza
AO
Lima
Paulo Teixeira
PT
Lacava
João Lúcio
JL
Azevedo
Welington Luiz
WL
Araújo
D000898:Antibiosis; D030008:Catharanthus / Q000382:microbiology*; D002480:Cellulase / Q000096:biosynthesis* / Q000235:genetics; D060026:Endophytes / Q000201:enzymology* / Q000235:genetics; D060847:Metabolic Engineering; D020601:Methylobacterium extorquens / Q000201:enzymology* / Q000235:genetics; D008855:Microscopy, Electron, Scanning; D010935:Plant Diseases / Q000517:prevention & control; D036226:Seedlings / Q000382:microbiology*; D044167:Xylella / Q000254:growth & development*; D052584:Xylem / Q000382:microbiology
D002480:Cellulase