Klebsiella pneumonia (K. pneumoniae) is a Gram-negative bacterium that causes nosocomial infections in the lung, bloodstream, and urinary tract. Therefore, detecting K. pneumoniae in early time is important in preventing severe infections. However, clinical detection of K. pneumoniae requires a long time of agar plate culture. Nucleic acid detection like qPCR is precise but requires expensive equipment. Recent research reveals that collateral cleavage activity of CRISPR-LbCas12a has been applied in nucleic acid detection. In this study, PCR combined with CRISPR-LbCas12a targeting the K. pneumoniae system was established. This system showed excellent detection specificity and sensitivity in both bench work and clinical samples. Due to its advantages, its application can meet different detection requirements in health centers where qPCR is not accessible.

RCH is known rapidly enhance cold tolerance of insects. Trehalose has been demonstrated to be one of the cryoprotectant in L. oryzophilus, an important invasive pest of rice in China. Trehalose synthesis mainly occurs through the TPS/TPP pathway in insects. In this study, LoTPS gene was cloned and characterized for the first time. Its expression and trehalose content changes elicited by RCH were investigated. Our results revealed that RCH not only increased the survival rate of adults but also upregulated the gene expression level of LoTPS and increased trehalose content under low temperature. We hypothesized upregulated LoTPS promoted trehalose synthesis and accumulation to protect adults from low-temperature damage. To further verify the function of LoTPS gene, we employed RNAi technology. Our findings showed that RCH efficiency disappeared and failed to increase the survival rate when the adults were fed dsRNA of LoTPS. Additionally, inhibiting LoTPS gene expression resulted in no significant difference in trehalose content between RCH and non-RCH treatments. Furthermore, the expression patterns of TRET and TRE were also affected. Collectively, these results indicate the critical role of LoTPS in L. oryzophilus cold resistance after RCH induction. LoTPS can enhance the survival ability by regulating trehalose metabolism. These findings contribute to further understanding of the role of TPS in insect cold resistance and invasiveness of L. oryzophilus. Moreover, RNAi of the LoTPS opens up possibilities for novel control strategies against L. oryzophilus in the future.