Bioassay for selection of biocontroller bacteria against bean common blight (Xanthomonas axonopodis pv. phaseoli)

Abstract

Emphasis has been given on selection of micro-organism for biological control. However, in order to evaluate the biological control potential of a great number of micro-organisms in a small period of time it is necessary to develop an efficient bioassay. Seven hundred and sixty bacterial isolates from different habitats, were selected for compatibility with Rhizobium leguminosarum bv. phaseoli (SEMIA 4077 e SEMIA 4080). Among them 596 isolates were ineffective against both rhizobia. Bean seeds immersed in suspension of each one of these isolates were agitated for 5 hours at 10 o C and sowed in non-sterilized soil. The plants were kept in greenhouse. After the development of cotyledonary and primary leaves, these were removed and bioassayed for Xanthomonas axonopodis pv. phaseoli (XAP) control. In the cotyledonary leaves, it was observed that the isolate DFs093 offered 100% control, DFs041 and DFs1297 offered 90% and DFs490, DFs769, DFs831, DFs842 and DFs843 offered 80% control. In the primary leaves, the DFs482 isolated offered 100% and the DFs080, DFs348, DFs513, DFs622, DFs769, DFs842 and DFs912 offered 80% of XAP control.

Interaction between bacterial biocontrol-agents and strains of Xanthomonas axonopodis pv. phaseoli effects on biocontrol efficacy of common blight in beans

“…DFs348 (isolated from onion leaf), Pseudomonas veronii DFs513 (isolated from onion tunic), P. fluorescens DFs831 and DFs842 (respectively isolated from snap and rhizosphere soil of common bean), DFs843 and DFs912 (Rhodococcus fascians isolated from bean leaf) used in this study were selected from a previous work on the control of Xap (Zanatta et al, 2007) and are maintained in the collection of the Plant Bacteriology Laboratory of the Federal University of Pelotas.…”

“…Control seeds were immersed in saline solution only (Zanatta et al, 2007). The treated twenty-five seeds were planted in a commercial substrate Plantmax ® in 500 g pots.…”

“…There are also many researches that show good results for bean diseases such as Macrophomina phaseolina (Torres et al, 2016), X. axonopodis pv. phaseoli (Zanatta et al, 2007;Sallan, 2011), Pseudomonas savastanoi pv. phaseolicola (Garret and Schwartz, 1998), Colletotrichum lindemuthianum (Corrêa et al, 2008;Bardas et al, 2009) and Pseudocercospora griseola (Corrêa et al, 2014).…”

Common Bacterial Blight (Xanthomonas axonopodis pv. phaseoli) of Beans with Special Focus on Ethiopian Condition

“…The same author stated that, in physiological studies, bean plants treated by Rahnella aquatilis exhibited higher phenolic compounds contents and higher activity of peroxidase enzyme than untreated plants. Bioassays have been carried out in Brazil to select a biological control agent for Xap [93]. Isolates from soil planted with beans, isolates from bean pods and from bean leaves offered variable control of between 80% to 100% to Xap.…”

Development of Integrated Disease Control Measures for the Valorisation of Traditional Crops in Southern Italy: The Case Study of Fagioli di Sarconi

“…Dissemination in the field is mainly determined by wind-driven rain and overhead irrigation, but also by insects, field workers and contaminated equipment (Gilbertson and Maxwell 1992;Saettler 1989), which may play an important role. Common bacterial blight is the major seed-borne disease of common bean worldwide (Tarlan et al 2001;Miklas et al 2003), and the best way to manage CBB includes the use of pathogen-free seed (Zanatta et al 2007). In order to control CBB, the use of bean cultivars with genetic tolerance/resistance to the disease is the most practical method (Coyne and Schuster 1974;Yoshii et al 1978) though the availability of CBB-resistant cultivars is limited.…”