Expression patterns of key iron and oxygen metabolism genes during magnetosome formation in M agnetospirillum gryphiswaldense MSR ‐1

To evaluate the expression patterns of genes involved in iron and oxygen metabolism during magnetosome formation, the profiles of 13 key genes in M agnetospirillum gryphiswaldense MSR ‐1 cells cultured under high‐iron vs. low‐iron conditions were examined. Cell growth rates did not differ between the two conditions. Only the high‐iron cells produced magnetosomes. Transmission electron microscopy observations revealed that magnetosome formation began at 6 h and crystal maturation occurred from 10 to 18 h. Real‐time polymerase chain reaction analysis showed that expression of these genes increased during cell growth and magnetosome synthesis, particularly for ferric reductase gene ( fer6 ) and ferrous transport system‐related genes feoAB1 , feoAB2 , sodB , and katG . The low‐iron cells showed increased expression of feoAB1 and feoB2 from 12 to 18 h but no clear expression changes for the other genes. Expression patterns of the genes were divided by hierarchical clustering into four clusters for the high‐iron cells and three clusters for the low‐iron cells. Each cluster included both iron and oxygen metabolism genes showing similar expression patterns. The findings indicate the coordination and co‐dependence of iron and oxygen metabolism gene activity to achieve a balance during the biomineralization process. Future transcriptome analysis will help elucidate the mechanism of biomineralization in MSR ‐1 magnetosome formation.