A single gene all3940 (Dps) overexpression in Anabaena sp. PCC 7120 confers multiple abiotic stress tolerance via proteomic alterations

Abstract

DNA-binding proteins (Dps) induced during starvation play an important role in gene regulation and maintaining homeostasis in bacteria. The nitrogen-fixing cyanobacterium, Anabaena PCC7120, has four genes annotated as coding for Dps; however, the information on their physiological roles is limiting. One of the genes coding for Dps, 'all3940' was found to be induced under different abiotic stresses in Anabaena and upon overexpression enhanced the tolerance of Anabaena to a multitude of stresses, which included salinity, heat, heavy metals, pesticide, and nutrient starvation. On the other hand, mutation in the gene resulted in decreased growth of Anabaena. The modulation in the levels of All3940 in Anabaena, achieved either by overexpression of the protein or mutation of the gene, resulted in changes in the proteome, which correlated well with the physiological changes observed. Proteins required for varied physiological activities, such as photosynthesis, carbon-metabolism, oxidative stress alleviation, exhibited change in protein profile upon modulation of All3940 levels in Anabaena. This suggested a direct or an indirect effect of All3940 on the expression of the above stress-responsive proteins, thereby enhancing tolerance in Anabaena PCC7120. Thus, All3940, though categorized as a Dps, is possibly a general stress protein having a global role in regulating tolerance to multitude of stresses in Anabaena.

Homologous overexpression of NpDps2 and NpDps5 increases the tolerance for oxidative stress in the multicellular cyanobacterium Nostoc punctiforme

“… 2016 ; Narayan et al. 2016 ). Heterologous overexpression of cyanobacterial Dps proteins in E. coli resulted in enhanced protection against oxidative stress in stationary phase cultures (Nair and Finkel 2004 ; Castruita et al.…”

“…PCC 7120, was recently found to enhance tolerance against multiple abiotic and biotic stresses (Narayan et al. 2016 ). The filamentous, heterocyst-forming cyanobacterium Nostoc punctiforme ATCC 29133 (from now on N. punctiforme ) has five Dps proteins encoded in the genome; NpDps1 ( Npun_R3258 ), NpDps2 ( Npun_F3730 ), NpDps3 ( Npun_R5701 ), NpDps4 ( Npun_R5799 ) and NpDps5 ( Npun_F6212 ) (Ekman et al.…”

Quantitative Proteomics Reveals the Protein Regulatory Network of Anabaena sp. PCC 7120 under Nitrogen Deficiency

“…It is noteworthy that the differentiation process can be inhibited if the nitrogen source is replenished during the time period of 9 to 12 h . By 24 h, the period of adaptation to the nitrogen deficiency, nearly all the heterocysts are mature with a full ability to fix nitrogen for the growth of cyanobacterial cells. , Although proteomic analyses have revealed the cellular mechanisms for nitrogen fixation and heterocyst differentiation in Anabaena 7120, − the previous studies on Anabaena 7120 focused mostly on the proteome changes caused by individual gene deletions or the specific proteomic changes occurring at a certain point after exposure to nitrogen stress. ,,− Additionally, these previous studies present several limitations due to the immaturity of the technology at the time they were published, such as low coverage of the proteome. Thus, it is necessary to explore the overall dynamic changes in the intracellular proteome of Anabaena 7120 in response to nitrogen stress with the proteomic technologies available nowadays.…”