Overexpression of phytochelatin synthase ( pcs ) enhances abiotic stress tolerance by altering the proteome of transformed Anabaena sp. PCC 7120

The present study provides data on the insertion of an extra copy of phytochelatin synthase (alr0975) in Anabaena sp. PCC 7120. The recombinant strain (AnFPN-pcs) compared to wild type showed approximately 22.3% increase in growth rate under UV-B, NaCl, heat, CuCl2, carbofuran, and CdCl2. It also registered 2.25-fold enhanced nitrogenase activity and 5-fold higher phytochelatin production. A comparison of the protein profile of wild type with the recombinant strain revealed that recombinant strain accumulated proteins belonging to the following categories: (i) detoxification (nutrient stress induced DNA binding protein, Mn-SOD, Alr0946 (CalA)), (ii) protein folding and modification (molecular chaperone DnaK, FKBP-type peptidyl-prolyl cis-trans isomerase), (iii) nucleotide and amino acid biosynthesis (dihydroorotase and Ketol-acid reductoisomerase), (iv) photosynthesis and respiration (coproporphyrinogen III oxidase, phycocyanin alpha chain, ferredoxin-NADP+ reductase), and (v) transport (sugar transport ATP-binding protein). Thus, it can be concluded that, above category proteins with their respective role in scavenging reactive oxygen species, proper folding of unfolded proteins, and protection of protein from degradation, sustained carbon fixation and energy pool and active transport of sugar together conceivably help the recombinant cyanobacterium (AnFPN-pcs) to cope with abiotic stress employed in the present study. Such recombinant strains have potential for future use as biofertilizer.