Heat shock protein(Hsp90),representing an important molecular chaperone in eukaryotic cells,plays particularly important roles in a variety of stress responses,development and signal transduction of plants.In this study,based on unigene sequences which were obtained from whole transcriptome sequencing of P.haitanensis,two full-length PhHsp90 genes were obtained by rapid amplification of cDNA ends(RACE),and named PhHsp90-1 and PhHsp90-2.The full-length cDNA of the PhHsp90-1 gene comprised 2 572 nucleotides and contained an open reading frame of 2 427 bp(GenBank accession:KF732652),encoding a protein of 809 amino acid residues with the predicted molecular weight of 90.2 kDa and theoretical isoelectric point of 4.79;and the full-length cDNA of the PhHsp90-2 gene comprised 2 510 nucleotides and contained an open reading frame of 2280bp(GenBank accession:KF732651),encoding a protein of 760 amino acid residues with the predicted molecular weight of 86.2 kDa and theoretical isoelectric point of 4.81.On the basis of conserved motifs and phylogenetic tree analysis,PhHsp90-1 belongs to the endoplasmic reticulum subfamily of Hsp90 and PhHsp90-2 belongs to the cytoplasmic subfamily of Hsp90.The expressions of the two PhHsp90 genes,as measured by real-time quantitative PCR,were significantly induced by high-temperature stress and desiccation stress,but had different expression patterns.Under high-temperature stress,the expression levels of the two PhHsp90 genes all significantly increased first and then decreased.However,during desiccation,the expression levels of PhHsp90-1 and PhHsp90-2 were significantly increased only when the water loss was >60%.These results suggested that the two PhHsp90s play important roles in the response to high-temperature stress and extreme desiccation stress.