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Abstract:  【Aim】 The small brown planthopper Laodelphax striatellus (Fallén), an important rice pest insect, feeds on rice and causes the decrease of yield and quality. Especially the rice stripe virus transmitted by L. striatellus induces more serious loss of rice. The small brown plant hopper is widely distributed and adapts to various environments. This study aims to clarify the molecular adaption mechanisms of L. striatellus under temperature stress preliminarily. 【Methods】 A full-length cDNA encoding Hsp90 from L. striatellus was cloned using RT-PCR and RACE technique. Different bioinformatics methods were used to analyze the characteristics of Hsp90. The expression levels of the Hsp90 gene among different developmental stages and under different temperatures were detected by the real-time PCR. 【Results】 The complete cDNA of LsHsp90 deposited in GenBank accession no. KF660250 is 2 740 bp in length, which encodes a protein of 729 amino acids, with the theoretical isoelectric point of 5.0 and molecular weight of 83.7 kDa. The amino acid sequence contains five signature sequences of Hsp90 family and a C-terminal cytoplasmic character sequence (EEVD). The LsHsp90 carries a classic Hsp90 family structural signature. The phylogenic tree demonstrated that LsHsp90 has high homology with Hsp90 proteins from some other insect species. The real-time PCR analyses exhibited that the expression levels of LsHsp90 varied remarkably in different developmental stages. The mRNA level observed was the highest in the 4th instar nymphs of L. striatellus, the lowest in female adults, and showed significant differences between male and female adults (P=0.008). The LsHsp90 mRNA level of L. striatellus could be induced by heat and cold temperature stress. The highest LsHsp90 mRNA level was observed at 40℃ and -9℃, respectively. At 40℃, LsHsp90 mRNA level reached a peak at 0.5 h after treatment, and then decreased with treatment time. However, at -4℃, the peak of LsHsp90 mRNA level was observed at 1 h after treatment. 【Conclusion】 The LsHsp90 gene in L. striatellus responds to temperature stress, and it may play an important role in the adaption process of the pest to temperature stress.

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