Real-time monitoring of Ralstonia solanacearum infection progress in tomato and Arabidopsis using bioluminescence imaging technology

Background Ralstonia solanacearum, one of the most devastating bacterial plant pathogens, is the causal agent of bacterial wilt. Recently, several studies on resistance to bacterial wilt have been conducted using the Arabidopsis-R. solanacearum system. However, the progress of R. solanacearum infection in Arabidopsis is still unclear. Results We generated a bioluminescent R. solanacearum by expressing plasmid-based luxCDABE. Expression of luxCDABE did not alter the bacterial growth and pathogenicity. The light intensity of bioluminescent R. solanacearum was linearly related to bacterial concentrations from 10(4) to 10(8) CFU center dot mL(-1). After root inoculation with bioluminescent R. solanacearum strain, light signals in tomato and Arabidopsis were found to be transported from roots to stems via the vasculature. Quantification of light intensity from the bioluminescent strain accurately reported the difference in disease resistance between Arabidopsis wild type and resistant mutants. Conclusions Bioluminescent R. solanacearum strain spatially and quantitatively measured bacterial growth in tomato and Arabidopsis, and offered a tool for the high-throughput study of R. solanacearum-Arabidopsis interaction in the future.

Automated summary

A bioluminescent R. solanacearum strain was generated by expressing plasmid-based luxCDABE, and its light intensity was linearly related to bacterial concentrations. The light signals of this strain were found to be transported from roots to stems via vasculature in tomato and Arabidopsis. The quantification of light intensity accurately reflected the difference in disease resistance between Arabidopsis wild type and resistant mutants. This bioluminescent strain offers a tool for high-throughput study of R. solanacearum-Arabidopsis interaction in the future.