Detection and quantification of Xanthomonas axonopodis pv. phaseoli and its variant fuscans in common bean seeds

Abstract

The common bacterial blight of common beans (CBCF), a disease caused by Xanthomonas axonopodis pv. phaseoli (Xap) and Xanthomonas axonopodis pv. phaseoli var. fuscans (Xapf), significantly reduces grain yield and seed quality. Because this bacterium is mainly disseminated through infected seeds, efficient detection of Xap and Xapf is important to assure the productivity and quality of the crop. In this study, various techniques that included different extraction techniques (two different incubation times, with and without centrifugation) and five culture media (Kado 523, GYCA, MXP, NSA, and PTSA) were tested for the detection of the seed-borne inoculum, using three different seed samples. Overnight incubation of the seeds, followed by centrifugation and incubation in Kado 523 resulted in higher extraction of Xap and Xapf. The best extraction technique was overnight incubation followed by centrifugation, and the best medium was PTSA. Among the tested culture media, PTSA provided better identification and counting of the bacterial colonies, thus allowing the quantification of the seed infection levels.

Reaction of common bean lines to Xanthomonas axonopodis pv. phaseoli and Curtobacterium flaccumfaciens pv. Flaccumfaciens

“…However, Denardin and Agostini (2013) and Silva et al (2013) described the complexity of pathogen identification on seeds and highlighted the importance of finding resistance sources, due to the wide dissemination of the pathogen in the producing areas of common bean.…”

Research Article Genetic diversity as an additional selection criterion in a carioca common bean recurrent selection program for resistance to common bacterial blight

“…fuscans (Schaad et al, 2006). Bactericides have not been an effective alternative to control this disease (Denardin and Agostini, 2013). The use of resistant cultivars and certified seeds, adequate use of irrigation, growing in non-infested soils, and crop rotation are the most effective methods for control of CBB (Maringoni and Lauretti, 1999;Singh and Miklas, 2015;Akhavan et al, 2013).…”

Potential of transmission of Pyricularia graminis-tritici from plant to seed and from seed to seedling in wheat genotypes with different degrees of blast resistance

“…The seed is one of the most efficient means of dispersion, survival and transmission for several phytopathogens (Machado, 1988;Garcia Junior et al, 2008;Denardin and Agostini et al, 2013;Siqueira et al, 2016;Etebu and Nwauzoma, 2017). Therefore, several aspects of the blast should be investigated, such as the relationship between the presence of the disease in field and the incidence of the fungus in seeds produced (Goulart et al, 1995).…”