A Comparative Study of Three Detection Techniques for Subsp. , the Causal Pathogen of Sugarcane Ratoon Stunting Disease.

The ratoon stunting disease (RSD), caused by the bacterium subsp (), is one of the most economically devastating diseases impacting sugarcane. RSD causes significant yield losses and variety degradation. Diagnosis of RSD is challenging because it does not exhibit any discernible internal and external symptoms. Moreover, the bacteria are very small and difficult to isolate, cultivate, and detect. In this study, conventional polymerase chain reaction (PCR), real-time quantitative PCR (RT-qPCR), and -loop-mediated isothermal amplification (-LAMP) were utilized to specifically detect the presence of pathogens in the juice from -infected sugarcane stalks and an -pMD18-T recombinant plasmid. The results showed that was a highly specific causal pathogen for RSD. All three techniques provided great reproducibility, while -LAMP had the highest sensitivity. When the DNA extract from -infected sugarcane juice was used as a template, -LAMP was 10 and 100 times more sensitive than RT-qPCR and conventional PCR, respectively. When the -pMD18-T recombinant plasmid was used as a template, -LAMP was as sensitive as RT-qPCR but was 10 times more sensitive than conventional PCR. Based on the -LAMP detection system established, adding 0.4 M loop primers (LF/LP) can accelerate the reaction and reduce the total time required. In addition, the optimal amount of DNA polymerase for -LAMP reactions was determined to be 6.0 U. The results provide technical support for the detection of RSD pathogen that will help manage sugarcane RSD.