Abstract: To understand the metabolic pathway of sulfur oxidation in extremely thermoacidophilic archaea,20 possible genes related to sulfur oxidation were preliminarily screened by NCBI database alignment based on the complete genome sequence of Acidianus manzaensis YN-25. Quantitative real-time PCR（RT-qPCR）was used to analyze the differential expressions of the screened genes under two different energy substrates,elemental sulfur（S⁰）and iron（Fe²⁺）. The results indicated that 15 genes were associated with sulfur oxidation from the compartive analysis of the experiment results ,including 5 genes encoding the enzymes of oxidizing S⁰ and sulfur-containing intermediates,4 genes encoding terminal oxidase,1 gene encoding sulfate transporter permease,1 gene encoding electron transfer protein,and 4 dsrE genes encoding sulfur reduction protein family closely related to sulfur oxidation. Based on the above result of analysis,a sulfur oxidation model of A. manzaensis was presented as below. Extracellular S⁰ was transported into the cell through membrane,and reduced by sulfur oxygenase-reductase（SOR）to be intermediates such as S₂O₃^2-,SO₃^2- and H₂S. Following,these sulfur-containing intermediates were further oxidized by relevant enzymes inside cells,and the electrons from the oxidation were transferred to oxidized quinone（Q²⁺）on the cell membrane,from which the reduced quinone（QH₂）was formed. QH₂ were eventually oxidized by terminal oxidase to be NADH and ATP providing energy for the growth of cells.

Key words: genome analysis, extremely thermoacidophilic archaea, Acidianus manzaensis, sulfur oxidation model