An Efficient Inoculation Technique to Assess the Pathogenicity of Pantoea Species Associated to Bacterial Blight of Rice.

Bacteria blight diseases of rice due to several genera of pathogenic bacteria are one of the major constraints worldwide for rice production. The disease can be best managed through host plant resistance sources. For most of these bacteria such as Xanthomonas oryzae pv. oryzae, X. oryzae pv. oryzicola, Pseudomonas fuscovaginae, Burkholderia glumae, Burkholderia gladioli and Acidovorax avenae subsp. avenae, specific diagnostic techniques that include molecular and pathogenicity tests have been developed. However, for Pantoea spp., information on pathogenicity assay is very limited and protocols used are not uniform. Most authors use the leaf clipping method. In this paper, we describe the protocol for mechanical inoculation of rice seedlings aged 35 days. The method consists of infiltrating bacterial suspensions at concentrations of 10(8) CFU/ml, with a needleless syringe into the intercellular and interveinal spaces of rice leaves underside at about 4-5 cm below the leaf tip. This method can be used for a standardized pathogenicity assessment, germplasm resistance evaluation for identifying and characterizing resistance sources.