Screening Wild Pepper Germplasm for Resistance to Xanthomonas hortorum pv. gardneri

Abstract

Bacterial spot disease on peppers is caused by four species of the genus Xanthomonas. This disease causes black spot lesions not only on the leaves but also on the fruit, leading to yield and quality loss. Xanthomonas species cause major disease outbreaks in tropical, subtropical and humid continental regions worldwide. Bacterial blight caused by xanthomonads occurs on both greenhouse- and field-grown peppers and is particularly important in areas characterized by hot and humid environmental conditions. As pesticides are currently not sufficiently effective in the control of bacterial spot, the development of pepper varieties resistant to Xanthomonas species, including X. hortorum pv. gardneri, is of primary importance for sustainable production. In our research, 119 lines of Capsicum baccatum from the USDA ARS gene bank (Griffin, GA) and MATE (Hungarian University of Agriculture and Life Sciences) were tested against strains of X. hortorum pv. gardneri under greenhouse conditions. Four accessions of the wild pepper species C. baccatum appeared to be resistant to seven strains of X. hortorum pv. gardneri in greenhouse trials. The resistant genotypes of X. hortorum pv. gardneri identified in this study can be used for the resistance gene pyramidation against different bacterial spotted Xanthomonas species in pepper.

Plant Breeding Supporting the Sustainable Field Crop Production

“…Specific hypersensitive response genes do not protect but destroy the cells affected by pathogens [25]. The nonpathogen-specific GDR plays the role of the plant immune system due to its low stimulus threshold and high reaction rate [26]. Tissue retention capacity can be increased by breeding to a level where the GDR alone can provide adequate protection for the plant.…”

“…Tissue retention capacity can be increased by breeding to a level where the GDR alone can provide adequate protection for the plant. In this case, the presence of specific hypersensitive reaction genes is unnecessary; sometimes it is even a burden to the plant [26]. Another important pathogen bacteria of pepper is bacterial spot disease caused by Xanthomonas hortorum p. gardneri, which causes star-shaped necrotic lesions on the foliage, stem, and fruit.…”

“…Resistance breeding programs successfully developed commercial pepper lines with hypersensitive and quantitative resistance to various Xanthomonas species. The new sources of resistance identified in [26] provide a basis for further work on breeding diseaseresistant varieties. It was documented that the different genotypes of Capsicum.…”