Histopathology of Klebsiella pneumoniae strain Borkar inciting root bark necrosis and wilt in pomegranate

Soil borne plant pathogenic bacteria generally causes wilting symptoms by infecting the vascular tissues of plant root. During April 2015, the pomegranate plants in the Arid Zone Fruit Research Project, Mahatma Phule Agricultural University, Rahuri, India exhibited some unusually wilted plants. The symptoms included yellowing of leaves of one or two twigs, followed by their drooping and subsequent death of infected twigs. Subsequently other twigs also showed infection and the entire plant die within 2-3 months. The root system of infected plant shows root bark necrosis lesions spread on the root bark (Figure 1). There was no vascular infection present in the root. The wilting without vascular infection was unusual and therefore the histopathology of root infection was undertaken to assess the infection site and nature of infection in the pomegranate root.