Laboratory of Molecular Phytobacteriology, Department of Plant Pathology, Universidade Federal de Viçosa, Viçosa, MG, Brazil.
Department of General Biology, Universidade Federal de Viçosa, Viçosa, MG, Brazil.
Phytopathology. 2020 Aug;110(8):1428-1436. doi: 10.1094/PHYTO-01-20-0020-R. Epub 2020 Jun 29.
Common bean () is one of the most consumed agricultural products in the world. Its production is affected by common bacterial blight (CBB) caused by pv. and pv. . In this work, we investigated the spectrum, genetics, and inheritance of common bean resistance to pv. . Inoculation of nine selected cultivars with an pv. strain showed that BRS Radiante and IAPAR 16 were resistant. These two cultivars were also resistant to six pv. strains of different geographic origins, demonstrating their broad-spectrum resistances. BRS Radiante sustained smaller pv. populations than two susceptible cultivars. Stomatal densities of IAPAR 16 and BRS Radiante were significantly higher than or not different from susceptible cultivars. BRS Radiante showed the lowest general combining ability values and the combination BRS Radiante × Carioca MG the lowest specific combining ability (SCA) values, revealing the capacity of BRS Radiante to increase resistance to pv. . Positive and negative parental SCA values indicated dominant and recessive genes involved in pv. resistance. Resistance of the BRS Radiante × Carioca MG cross segregated in a 9:7 ratio in the F population, indicating that it is governed by two complementary dominant genes. Maximum likelihood analysis showed that the resistance of BRS Radiante to pv. is conferred by a gene of major effect with contribution of additional polygenes. This study contributes with important knowledge on the resistance against CBB in Brazilian common bean cultivars as well as with molecular tools for confirmation of common bean hybrids.
菜豆是世界上消费最多的农产品之一。其生产受到 pv. 和 pv. 引起的普通细菌性疫病（CBB）的影响。在这项工作中，我们研究了菜豆对 pv. 的抗性的谱、遗传和遗传。用 pv. 菌株接种 9 个选定的品种表明，BRS Radiante 和 IAPAR 16 具有抗性。这两个品种对来自不同地理来源的六种 pv. 菌株也具有抗性，表现出广谱抗性。BRS Radiante 维持的 pv. 种群比两个易感品种小。IAPAR 16 和 BRS Radiante 的气孔密度明显高于或与易感品种没有差异。BRS Radiante 表现出最低的一般配合力值，而 BRS Radiante × Carioca MG 的组合表现出最低的特殊配合力（SCA）值，表明 BRS Radiante 有能力增加对 pv. 的抗性。正的和负的亲本 SCA 值表明 pv. 抗性涉及显性和隐性基因。BRS Radiante × Carioca MG 杂交 F 群体中的抗性呈 9:7 分离，表明其由两个互补的显性基因控制。最大似然分析表明，BRS Radiante 对 pv. 的抗性由一个主效基因赋予，并由额外的多基因贡献。这项研究为巴西菜豆品种对 CBB 的抗性提供了重要的知识，并为确认菜豆杂种提供了分子工具。
