Abstract: Spirulina innermongoliansis is a high quality variety with normal temperature adaptability, which was found in salt lake in Inner Mongolia. Because of its later discovering history, and its special living conditions and other related reasons, S. innermongoliansis have not be widely studied and exploited in molecular genetics. Improving its heat resistance could expand its breeding range and reduce the farming costs. Some researches showed that heat shock protein played an important role in heat resistance of algae. This present study used PCR technology to gain HSP90 gene sequences in S. innermongoliansis, and then analyzed the gene sequence and its encoding protein gene sequence. Meanwhile, according to the genetic transformation of algae, we constructed a three pro\|integration expression vector, whose initiation codon ATG was 6 bp away from HSP90 gene. Three pro-integration expression vector had a cyanobacterial replication origin, a Bom gene, a promoter (BetaP) and a chloramphenicol resistance gene (Cm), which was essential to three pro-integration, then connected the gene HSP90. Therefore, this research was a necessary foundation to gain a new strain of S. innermongoliansis which had a higher heat resistance．

Key words: Spirulina innermongoliansis, heat resistance, HSP90, expression vector, three pro-integration