Characterization and Genetic Diversity of Pseudomonas syringae pv. syringae Isolates Associated with Rice Bacterial Leaf Spot in Heilongjiang, China.

Abstract

Simple SummaryIn Northeast China, rice bacterial brown leaf spot caused by Pseudomonas syringae pv. syringae is among the most damaging rice diseases. This disease results in significant yield losses. This study focuses on a comprehensive analysis of the pathogen, population structure, and genetic diversity within the species based on biochemical tests and genetic characterizations. Our results indicate high genetic heterogeneity in Pseudomonas syringae pv. syringae isolates, and clustering of testing isolates and reference strains are related with the genomospecies 1. This work contributes to the physiological classification of the P. s. pv. syringae isolated from Heilongjiang Province, China and the results present new data concerning the phylogeny and genetic diversity. Such studies have not been reported about P. s. pv. syringae from this region yet.In China, rice is one of the most important cereal crops. Rice bacterial brown leaf spot caused by P. s. pv. syringae is among the most damaging rice diseases in the Heilongjiang Province of China and results in substantial yield losses. In this study, a comprehensive analysis of the pathogen, population structure, and genetic diversity within the species was performed. For this purpose, 176 bacterial isolates of P. s. pv. syringae collected from 15 locations were characterized by using biochemical tests such as the LOPAT test, and genetic characterizations such as multilocus sequence analysis (MLSA) and repetitive PCR, using BOX, REP and ERIC primers. Biochemical testing and detection of syrB genes confirm the presence of P. s. pv. syringae, genetic characterization by MLSA and genetic fingerprinting by repetitive PCR confirmed that high genetic heterogeneity exists in the P. s. pv. syringae isolates, and clustering of the tested isolates and reference strains are related with the same genomospecies 1. This work contributes to the physiological classification of the P. s. pv. syringae isolated from Heilongjiang Province, China, and the results present new data concerning the phylogeny and genetic diversity. This type of study about P. s. pv. syringae has been not reported from this region until now.