First report of Pseudomonas syringae pv. lapsa causing leaf streak and black chaff of winter wheat in southwest Iran.
From 2014-18, a reoccurring disease was observed on winter wheat cvs. Pishgam, Back-cross Roshan, Mihan, Alvand, and Omid in Iran. The disease occurred on leaves and glumes. On leaves, the symptoms started as small water-soaked spots or streaks, which turned brown after a few days. Bacterial oozing was observed on leaves and glumes, under high humidity, before sunrise. As the disease progressed, glumes became brown to dark stained and brown to black spots developed on seeds. Based on morphological, physiological, molecular data (sequence analysis) and pathogenicity test, the causal pathogen was identified as Pseudomonas syringae pv. lapsa. This is thought to be the first report of P. syringae pv. lapsa causing bacterial leaf streak and black chaff disease on winter wheat in Iran.