Identifying and characterizing the main causal pathogen responsible for rice grain discoloration in Pakistan

Grain discoloration affects grain quality, quantity, and yield of rice crop worldwide. Herein, morphological, molecular, and pathogenic characterizations of the pathogen causing rice grain discoloration were performed. A set of 20 rice genotypes were scored for disease infestation in field and scanned with 12 unlinked polymorphic SSR primer pairs for genetic diversity assay. Pathogens from the discolored rice panicles were isolated to investigate the disease-causing pathogen on DNA sequencing basis. The universal primer pairs were used for DNA sequencing of the isolated pathogen. Furthermore, the new pathogen was reconfirmed morphologically by using Koch’s postulates. The bacterial species Bacillus licheniformis was identified as a major pathogen causing grain discoloration disease in rice. The genotypes found to be resistant to rice grain discoloration include Super-basmati, Rondo, Gulfmont, KSK-133 and L-203 which can be used as potential genetic resources for breeding rice grain discoloration resistant cultivars. The study provided information to the researchers and farmers for managing and controlling rice grain disease by the adoption of Bacillus licheniformis. The study is equally beneficial both for researchers and scientific community to start up a new research program by utilization of this study