Determination of responses of different bean cultivars against races of Pseudomonas syringae pv phaseolicola, causal agent of halo blight of bean

Abstract

Use of resistant plant varieties combined with other disease management practices is regarded as the most practical approach to control of seedborne bacterial disease agents. In this study, responses of different bean cultivars to nine different races of Pseudomonas syringae pv phaseolicola, the causal agent of bacterial halo blight of common bean (Phaseolus vulgaris L.), were determined. During compatible interaction in susceptible cultivars, virulent bacterial races caused water soaked lesion at sites of inoculation. Similar lesions developed in moderately resistant cultivars but symptoms were later associated with more tissue browning around the sites of inoculation. In contrast, the resistant response, produced the characteristic hypersensitive reaction (HR), was characterized as a small discrete browning and tissue collapse at site of inoculation. No local cultivars showed complete resistance to all races tested. Bean cultivars Sehirali-90 and Göynük-98 were found to be resistant or moderately resistant to five different bacterial races. Bean cultivar, Karacaşehir-90, on the other hand, was found to be resistant or moderately resistant to six different bacterial races. Analysis of bacterial growth and the accumulation of isoflavonoid bean phytoalexin, phaseollin in planta were carried out for tissues expressing compatible and incompatible interactions to enable a link to be made between reaction phenotypes and restriction of bacterial growth and phytoalexin accumulations. Development of the HR was clearly associated with the restricted multiplication of bacteria during incompatible interactions. A time-course accumulation analysis on pods treated with different races of bacterial agent showed that a strong correlation was observed between the timing and extent of cell death and accumulation of phaseollin, being rapid and extensive in incompatible interactions compared to compatible interaction.

Are we killing the rain? Meditations on the water cycle and, more particularly, on bioprecipitation

“…5. P. syringae received sustained research attention, therefore, as an aggressive and successful pathogen responsible for basal kernel blight in respect to barley (Braun-Kiewnick et al 2000); as a principal causal agent of halo blight in many bean cultivars (Bozkurt and Soylu 2011); as a prolific cause of bacterial shoot blight in tea plants, widely infecting them in tea-growing countries such as Japan (Tomihama et al 2009); and as an antagonist of tomato plants, on which it causes a blight called bacterial speck across the world (see e.g. de-Bashan 2002a, 2002b with the author.…”

Registration of Common Bean Pinto US14HBR6 Resistant to Race 6 of the Halo Blight Pathogen, Pseudomonas syringae pv. phaseolicola

“…27. Quantitative halo blight resistance (i.e., to multiple races) has also been reported by others (Bozkurt and Soylu, 2011;Mills and Silbernagel, 1992;Yaish et al, 2006). he objective of this study was to identify a source of resistance to Psp race 6 in common bean that could be used in a breeding program to develop halo blight-resistant cultivars.…”

“…A halo blight outbreak in Wyoming in 2009, for example, compromised thousands of hectares of certified common bean seed production. Halo blight is also endemic in relatively humid central Mexican highlands, Guatemala, the Andes, central and southern Brazil, Argentina, Spain, Turkey, South Africa, and countries in East Africa (e.g., Tanzania) (Bozkurt and Soylu, 2011; Schwartz, 1989). In central Wisconsin, Minnesota, Colorado; Castilla and Leon in Spain; and various countries in East Africa, halo blight can be sympatric with and occur on the same cultivars with other bacterial diseases such as common bacterial blight, caused by Xanthomonas campestris pv.…”

“…Newly emerging leaves may be stunted and light green to yellow, due to the systemic movement of the phaseolotoxin produced by Psp . Pod symptoms begin as small water‐soaked lesions that expand into large water‐soaked spots surrounded by a necrotic brown margin (Bozkurt and Soylu, 2011; Schwartz, 1989). Seed from infected pods may be abnormal in size, shape, and color and may be heavily contaminated with Psp .…”

“…A halo blight outbreak in Wyoming in 2009, for example, compromised thousands of hectares of certiied common bean seed production. Halo blight is also endemic in relatively humid central Mexican highlands, Guatemala, the Andes, central and southern Brazil, Argentina, Spain, Turkey, South Africa, and countries in East Africa (e.g., Tanzania) (Bozkurt and Soylu, 2011;Schwartz, 1989 he halo blight bacterium infects and contaminates common bean seed, from which it establishes epiphytic populations that can colonize tissues of susceptible plants endophytically (Godfrey et al, 2010). he initial symptoms of halo blight in leaves are small water-soaked spots that enlarge into angular necrotic lesions surrounded by a light greenish-yellow halo (Schwartz, 1989).…”