Optimization of a genetic transformation method for Acidovorax avenae, the causal agent of red stripe disease of sugarcane

BERTANIA, R.; MIELNICHUCK, N.; PERERA, M. F.; GONZALEZ, V; VOJNOV, A.A.; CUENYA, MI; CASTAGNARO, AP

San Miguel de Tucumán

Congreso; ISSCT XXX Congress; 2019

Acidovorax avenae is the causal agentof red stripe, one of the main bacterial diseases that affect the sugarcanecrop in Tucumán, Argentina. Because information on sugarcane colonization andmovement of A. avenae duringinfections is limited, the aim of this study was to develop tools to monitorthe bacteria during the disease cycle. Three A. avenae transformation methods were tested: chemical,electroporation and conjugation using plasmids containing different fluorescentproteins and antibiotic selective genes. Mutant A. avenae strains were evaluated for antibiotic resistance andexpression of fluorescence signals.  Inaddition, their identity was confirmed by PCR. Only transformation byconjugation presented stable fluorescent expression in the bacterium. TheAa::pHC60-gfp showed the highest expression of the gfp gene. In vitro assaysshowed that the growth of the Aa::pHC60-gfp mutant in liquid media did notdiffer from that of the wild type.  Inaddition, plants inoculated either with the GFP carrying strain or the wildtype presented comparable incidence and severity 15 days after inoculation.This is the first report of an A. avenaemutant strain expressing a heterologous gene and represents a valuable tool tostudy the biology of the bacterium and its colonization in sugarcane.