Novel adaptive responses revealed by transcription profiling of a Synechocystis sp. PCC 6803 (delta)isiA mutant in the presence and absence of hydrogen peroxide

• Published in: Photosynthesis research Vol. 84; no. 1-3; pp. 65 - 70
• Main Authors: Singh, A.K, Li, H, Bono, L, Sherman, L.A
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Nature B.V 01.06.2005
• Subjects: bacterial proteins; chlorophyll-binding protein; Cyanobacteria; Gene expression; gene expression regulation; hydrogen peroxide; Oxidative stress; Proteins; Synechocystis; Synechocystis sp. PCC 6803; transcription (genetics)
• ISSN: 0166-8595; 1573-5079
• DOI: 10.1007/s11120-004-6429-x

The isiAB genes have proven to be highly stress-responsive under a variety of environmental conditions, including iron deficiency, high salt and oxidative stress. In order to understand the function of IsiA and its importance in oxidative stress, we constructed a knock out mutant of the isiA gene and compared differential gene expression of the ΔisiA strain in the presence and absence of H^sub 2^O^sub 2^. We used the full genome microarray for the cyanobacterium Synechocystis sp. PCC 6803 as previously described [Postier BL, Wang HL, Singh A, Impson L, Andrews, HL, Klahn J, Li H, Risinger G, Pesta D, Deyholos M, Galbraith DW, Sherman LA and Burnap RL (2003) BMC Genenomics 4: 23-34]. We determined that one of the main differences in ΔisiA compared to wild-type (in the absence of peroxide) was the induction of a gene cluster (sll1693-sll1696) that encoded genes resembling pilins or general secretory proteins (Gsp). These proteins are targeted to the cytoplasmic membrane and we suggest that they may be involved in the assembly of membrane complexes, including pigment-protein complexes. The ΔisiA strain was more resistant to H^sub 2^O^sub 2^ compared to the wild-type. In the presence of 1.5mM H^sub 2^O^sub 2^ for 30min, a cluster of genes that includes a peroxiredoxin was induced 7- to 8-fold and we suggest that this peroxide scavenging enzyme is responsible for the increased peroxide resistance of the ΔisiA strain.[PUBLICATION ABSTRACT]