Abstract: Powdery mildew is one of the major leaf diseases in growth of rubber tree.Heat shock protein 90（HSP90）molecular chaperone plays an important role in plant stress resistance.To study the structure of the rubber tree HSP90 family members and their function in powdery mildew resistance,Hb HSP90.8-1 was cloned from rubber tree variety Reyan73397 leaf using PCR technology and its structure and function were analyzed by bioinformatics method.The results showed that the c DNA sequence of Hb HSP90.8-1 was 2 844 bp in full length,2 454 bp open reading frame（ORF）and encoded 817 amino acids.Hb HSP90.8-1 encoded a stable hydrophilic protein with signal peptide,no transmembrane structure and predicted positioning on endoplasmic reticulum,contained HSP90 superfamily and HATPase superfamily domains.Phylogenetic analysis showed that Hb HSP90.8-1 was closely related to Me HSP90,and classified into Jatropha Jc HSP90 and Castor Rc HSP90.The q RT-PCR analysis showed that Hb HSP90.8-1 was expressed in different tissues of rubber tree,and its expression level was the highest in latex.The expression of Hb HSP90.8-1 was significantly expressed and upregulated in leaves treated with Oidium heveae infection,H2O2,ABA and ETH respectively.However,under the treatment of Me JA and SA hormone,the expression of Hb HSP90.8-1 showed a downward trend.The study suggested that Hb HSP90.8-1 related to the powdery mildew resistance and the hormone signal transduction pathway related to plant disease resistance,and provided a technical guidance for the subsequent study on the molecular regulation mechanism of Hb HSP90.8-1 in the powdery mildew resistance in rubber tree.