RESUMO
Pantoea ananatis is a major pathogen that causes the new bacterial blight in rice, and its symptoms very similar to rice bacterial blight. Therefore, there is a dire need for an accurate and rapid method for detecting P. ananatis. In this study, an early and rapid visual detection method for P. ananatis was established. Using GyrB gene as the target sequence, an innovative recombinase-aided amplification detection system integrated with a lateral flow dipstick (RAA-LFD) was constructed. The optimized RAA-LFD detection method can be initiated at body temperature and does not rely on precise instruments. It does not require DNA extraction and can be used directly with plant tissue fluids. The results can be visualized after 10 minutes of amplification. The specificity and sensitivity tests showed that the RAA-LFD method could detect P. ananatis, whereas other common plant pathogens were not detected, and its detection sensitivity for P. ananatis DNA reached 100 copies/µL. The detection of diseased tissues indicated that this method could accurately detect P. ananatis in artificially inoculated rice tissues in the early stages of infection before symptoms. The RAA-LFD detection system established in this study is simple and fast, with visual results, excellent specificity, and high sensitivity. It is semi-quantitative and should be used for the early detection and rapid field diagnosis of new leaf blight, which provides technical support for the early warning and real-time detection of field samples.
RESUMO
A group of SARS-Iike coronaviruses(SL-CoV)have been identified in horseshoe bats.Despite SL-CoVs and SARS-CoV share identical genome structure and high-level sequence similarity,SL-CoV does not bind to the same cellular receptor as for SARS-CoV and the N-terminus of the S proteins only share 64% amino acid identity,suggesting there are fundamental differences between these two groups of coronaviruses.To gain insight into the basis of this difference,we established a recombinant adenovirus system expressing the S protein from SL-CoV(rAd-Rp3-S)to investigate its immune characterization.Our results showed that immunized mice generated strong humoral immune responses against the SL-CoV S protein.Moreover,a strong cellular immune response demonstrated by elevated IFN-γ and IL-6 levels was also observed in these mice.However,the induced antibody from these mice had weaker cross-reaction with the SARS-CoV S protein,and did not neutralize HIV pseudotyped with SARS-CoV S protein.These results demonstrated that the immunogenicity of the SL-CoV S protein is distinct from that of SARS-CoV,which may cause the immunological differences between human SARS-CoV and bat SL-CoV.Furthermore,the recombinant virus could serve as a potential vaccine candidate against bat SL-CoV infection.
