First report of tobacco root rot caused by Gelasinospora reticulata

In August 2012, a new tobacco root disease was observed in a number of tobacco fields in Shi-Ka Village, Pianbai Town, Youyang County of Chongqing City, China. The disease incidence varied from 10% to 40%, and the seedling mortality ranged from 50% to 80%. Affected tobacco plants developed symptoms characterized by a progressive yellowing and wilting of leaves, brown or black streaks in the stems, and root necrosis that eventually lead to the death of the plant. In this study, we were able to confirm field observations in the greenhouse using fungal isolates. The seedling mortality rate under artificial inoculation was 100%. The results of a pathogenicity test and morphological studies as well as rDNA internal transcribed spacer (ITS) and β-tubulin sequence analyses indicated that the disease was caused by Gelasinospora reticulata. This is a novel root rot disease on tobacco caused by this pathogen.