An improved control efficacy against tobacco bacterial wilt by an engineered Pseudomonas mosselii expressing the ripAA gene from phytopathogenic Ralstonia solanacearum

Abstract

The environmental bacterium Pseudomonas mosselii produces antagonistic secondary metabolites with inhibitory effects on multiple plant pathogens, including Ralstonia solanacearum, the causal agent of bacterial wilt. In this study, an engineered P. mosselii strain was generated to express R. solanacearum ripAA, which determines incompatible interactions with tobacco plants. The ripAA gene together with its native promoter was integrated into the P. mosselii chromosome. The resulting strain showed no difference in antimicrobial activity against R. solanacearum. Promoter-LacZ fusion and RT-PCR experiments demonstrated that the ripAA gene was transcribed in culture media. Compared with that of the wild type, the engineered strain reduced the disease index by 9.1% for bacterial wilt on tobacco plants. A transcriptome analysis was performed to identify differentially expressed genes in tobacco plants, and the results revealed that ethylene- and jasmonate-dependent defense signaling pathways were induced. These data demonstrated that the engineered P. mosselii expressing ripAA enables improved biological control against tobacco bacterial wilt by the activation of host defense responses.

The natural pyrazolotriazine pseudoiodinine from Pseudomonas mosselii 923 inhibits plant bacterial and fungal pathogens

“…For example, the c-xtl gene cluster involved in xantholysin biosynthesis was discovered in P. mosselii BS011 and inhibited the development of M. oryzae 45 . Recently, an engineered P. mosselii strain expressing the ripAA gene effectively suppressed bacterial wilt in tobacco 46 . Moreover, a novel insecticidal protein from P. mosselii designated PIP-47Aa was effective in controlling the corn rootworm 47 .…”

Identification and Characterization of a Pseudomonas mosselii strain and its Antibacterial Function against Agrobacterium tumefaciens

“…P. mosselii has been reported to been characterized in biocontrol against plant disease. Recently, Zhou and colleges generated an engineered P. mosselii strain to express Ralstonia solanacearum ripAA gene, which determines incompatible interactions with tobacco plants to control tobacco bacterial wilt [36]. A gene cluster named cxtl from P. mosselii BS011 documented to be required for inhibitory activity against the fungus Magnaporthe oryzae [37].…”

“…Gene deletion experiments demonstrated that the gene cluster named c-xtl from P. mosselii BS011 documented to be required for the inhibitory activity [35]. Engineering of Ralstonia solanacearum ripAA gene to P. mosselii strain is efficient to control tobac-co bacterial wilt [36]. A drafted genome sequence of P. mosselii Gil3 predicted for the synthesis of antimicrobial compound xantholysin and a ppyS homologous gene for synthesis of antibiotic pseudopyronines [38].…”