Rapid cold hardening (RCH) is known to rapidly enhance the cold tolerance of insects. Trehalose has been demonstrated to be a cryoprotectant in Lissorhoptrus oryzophilus, an important invasive pest of rice in China. Trehalose synthesis mainly occurs through the Trehalose-6-phosphate synthase (TPS)/trehalose-6-phosphate phosphatase (TPP) pathway in insects. In this study, the TPS gene from L. oryzophilus (LoTPS) 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 expression level of LoTPS and increased the trehalose content under low temperature. We hypothesized that upregulated LoTPS promoted trehalose synthesis and accumulation to protect adults from low-temperature damage. To further verify the function of the LoTPS gene, we employed RNA interference (RNAi) technology. Our findings showed that RCH efficiency disappeared and the survival rate did not increase when the adults were fed dsRNA of LoTPS. Additionally, inhibiting LoTPS expression resulted in no significant difference in trehalose content between the RCH and non-RCH treatments. Furthermore, the expression patterns of trehalose transporter (TRET) and trehalase (TRE) were also affected. Collectively, these results indicate the critical role of LoTPS in L. oryzophilus cold resistance after RCH induction. LoTPS can enhance survival ability by regulating trehalose metabolism. These findings contribute to further understanding the role of TPS in insect cold resistance and the invasiveness of L. oryzophilus. Moreover, RNAi of LoTPS opens up possibilities for novel control strategies against L. oryzophilus in the future.

With the increase of world food demand, the intensity of cultivated land use also increased. To improve soil nutrient concentrations and crop yield, several straw returning techniques have been developed. Studies have shown that straw returning is beneficial to soil, but few studies have focused on the relationship between microbes and fertility in seasonal freeze-thaw periods. A two-year cropland experiment was set up that comprised three different straw return strategies, namely covering tillage with straw return for two years (CS), rotary tillage and straw return for two years (RS), rotary covering tillage with straw return (first year covering and the second year rotary tillage) (CRS), and conventional tillage with no straw return (CK). Illumina Miseq high throughput sequencing of 16S rRNA was applied to assess bacteria community structure. The relationship between bacteria community structure and changes in soil fertility induced by different straw incorporating during seasonal trends was studied. Our results showed that soil bacterial communities varied significantly during the soil seasonal freeze-thaw period in the northwest of Jilin province, China, and were influenced, to some extent, by the different straw returning procedures. Multidimensional analysis revealed that total phosphorus (TP), available nitrogen (AN), and total nitrogen (TN) were the major drivers of bacterial community structure. The co-occurrence network was divided into several modules. Notably, the major bacterial modules varied significantly in different sampling periods and different treatments. These results suggested that specific bacterial groups could contribute to soil fertility in relation to environmental fluctuations. Some bacterial groups (e.g., Pyrinomonadales, Rhizobiales, Sphingomonadales, and Xanthomonadales, in order level) were directly linked with specific environmental factors, indicating the key roles of these groups in soil fertility. In summary, the soil bacterial communities varied significantly during the freeze-thaw period and might play important roles in the degradation of straw. Thus, the straw return could enhance soil fertility.

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.