Enterobacter asburiae and Pantoea ananatis Causing Rice Bacterial Blight in China

Abstract

Rice bacterial blight is a devastating bacterial disease threatening rice yield all over the world and Xanthomonas oryzae pv. oryzae (Xoo) is traditionally believed as the pathogen. In recent years, we have received diseased rice samples with symptoms of blight leaves from Sichuan and Guangdong Provinces, China. Pathogen isolation and classification identified two different enterobacteria as the causal agents, namely as Enterobacter asburiae and Pantoea ananatis. Among them, E. asburiae was isolated from samples of both Provinces, and P. ananatis was only isolated from the Sichuan samples. Different from rice foot rot pathogen Dickeya zeae EC1 and rice bacterial blight pathogen Xoo PXO99A, strains SC1, RG1 and SC7 produced rare cell wall degrading enzymes (CWDEs) but more extrapolysaccharides (EPS). E. asburiae strains SC1 and RG1 produced bacteriostatic substances while P. ananatis strain SC7 produced none. Pathogenicity tests indicated that all of them infected monocotyledonous rice and banana seedlings, but not dicotyledonous potato, radish or cabbage. Moreover, strain RG1 was most virulent, while strains SC1 and SC7 were similar virulent on rice leaves, even though strain SC1 propagated significantly faster in rice leaf tissues than strain SC7. This study firstly discovered E. asburiae as a new pathogen of rice bacterial blight, and in some cases, P. ananatis could be a companion pathogen. Analysis on production of virulence factors suggested that both pathogens probably employ a different mechanism to infect hosts other than using cell wall degrading enzymes to break through host cell walls.

Cloacaenodin, an Antimicrobial Lasso Peptide with Activity against Enterobacter

“…E. cloacae is the most clinically relevant strain that we found activity against, as this pathogen is a frequent cause of nosocomial infections around the globe . The other strains that we found as susceptible to cloacaenodin are known to be causative agents for certain plant diseases or occasional human pathogens. − …”

Microbial Diversity Analysis and Genome Sequencing Identify Xanthomonas perforans as the Pathogen of Bacterial Leaf Canker of Water Spinach (Ipomoea aquatic)

“…For instance, P. ananatis was found to synergistically infect Eucalyptus along with a fungal pathogen, Corniothyrium zuluense , causing serious canker disease ( Van Zyl, 1999 ). Recently, we also isolated two bacterial pathogens from the same diseased rice sample, namely, Enterobacter asburiae and P. ananatis , both of which were determined as the causal agents of rice bacterial blight with no detectable synergistic or antagonistic interactions ( Xue et al, 2020 ). Moreover, Dickeya zeae and Stenotrophomonas maltophilia have been isolated from the same tissue of soft rot leaf of Clivia miniata with no synergism ( Hu et al, 2018 , 2021 ).…”

Isolation and Genome Analysis of Pectobacterium colocasium sp. nov. and Pectobacterium aroidearum, Two New Pathogens of Taro

“…To determine whether strains LJ1 and LJ2 promote or inhibit each other in planta, we measured the bacterial cell numbers by counting their corresponding colony-forming units (CFU) according to the method previously described ( Hu et al, 2021a ; Xue et al, 2021 ). Firstly, we visualized these two strains by, respectively, importing plasmids pBBP gdh (pmCherry) ( Liao et al, 2018 ) and pLAFR3-GFP (pGFP) ( Shi et al, 2019 ) into strains LJ1 and LJ2 by triparental mating with the help of E. coli HB101(RK2013).…”