Ruchi Rai

A new arsenate reductase involved in arsenic detoxification in Anabaena sp. PCC7120.

In silico analysis followed by experimental validation leads us to propose that the predicted protein All0195 of Anabaena sp. PCC7120 showing enhanced expression under sodium arsenate (Na2HAsO4) stress belongs to the thioredoxin superfamily with structural similarity to bacterial arsenate reductase. The All0195 protein demonstrated C-X-TC-X-K, NTSG-X2-YR, and D-X2-L-X-KRP as functional motifs that show similarity to seven known bacterial arsenate reductase family protein homologs with Cys, Arg, and Pro as conserved residues. In view of physicochemical properties, such as aliphatic index, ratio of Glu + Lys to Gln + His, and secondary structure, it was evident that All0195 was also a thermostable protein. The predicted three-dimensional structure on molecular docking with arsenate oxyanion (

Comparative proteomics of wild type, An+ahpC and An∆ahpC strains of Anabaena sp. PCC7120 demonstrates AhpC mediated augmentation of photosynthesis, N2-fixation and modulation of regulatory network of antioxidative proteins.

HAsO_4^{- 2 }

Cyanobacterial Biodiversity and Biotechnology: A Promising Approach for Crop Improvement

) revealed its interaction with conserved Cys residue as also known for other bacterial arsenate reductase. In silico derived properties were experimentally attested by cloning and heterologous expression of all0195. Furthermore, this protein functionally complemented the arsenate reductase-deficient sodium arsenate-hypersensitive phenotype of Escherichia coli strainWC3110 (ΔarsC) and depicted arsenate reductase activity on purification. In view of the above properties, All0195 appears to be a new arsenate reductase involved in arsenic detoxification in Anabaena sp. PCC7120.

Application of Allele-Specific (AS-PCR) Marker for Identification of High-Molecular-Weight Glutenin Subunits (HMW-GS) at the GluB-1 Locus in Bread Wheat (Triticum aestivum L.)

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.

Cyanobacteria: Role in Agriculture, Environmental Sustainability, Biotechnological Potential and Agroecological Impact

UNLABELLED Alkylhydroperoxide reductase (AhpC), a 1-Cys peroxiredoxin is well known for maintaining the cellular homeostasis. Present study employs proteome approach to analyze and compare alterations in proteome of Anabaena PCC7120 in overexpressing (An+ahpC), deletion (An∆ahpC) and its wild type. 2-DE based analysis revealed that the major portion of identified protein belongs to energy metabolism, protein folding, modification and stress related proteins and carbohydrate metabolism. The two major traits discernible from An+ahpC were (i) augmentation of photosynthesis and nitrogen fixation (ii) modulation of regulatory network of antioxidative proteins. Increased accumulation of proteins of light reaction, dark reaction, pentose phosphate pathway and electron transfer agent FDX for nitrogenase in An+ahpC and their simultaneous downregulation in AnΔahpC demonstrates its role in augmenting photosynthesis and nitrogen fixation. Proteomic data was nicely corroborated with physiological, biochemical parameters displaying upregulation of nitrogenase (1.6 fold) PSI (1.08) and PSII (2.137) in An+ahpC. Furthermore, in silico analysis not only attested association of AhpC with peroxiredoxins but also with other players of antioxidative defense system viz. thioredoxin and thioredoxin reductase. Above mentioned findings are in agreement with 33-40% and 40-60% better growth performance of An+ahpC over wild type and An∆ahpC respectively under abiotic stresses, suggesting its role in maintenance of metabolic machinery under stress. SIGNIFICANCE Present work explores key role of AhpC in mitigating stress in Anabaena PCC7120 through combined proteomic, biochemical and in silico investigations. This study is the first attempt to analyze and compare alterations in proteome of Anabaena PCC7120 following addition (overexpressing strain An+ahpC) and deletion (mutant An∆ahpC) of AhpC against its wild type. The effort resulted in two major traits in An+ahpC as (i) augmentation of photosynthesis and nitrogen fixation (ii) modulation of regulatory network of antioxidative proteins.

Identification and functional characterization of four novel aldo/keto reductases in Anabaena sp. PCC 7120 by integrating wet lab with in silico approaches

Sustainable agriculture is advantageous over conventional agriculture for its capacity to accomplish food demand by utilizing environmental resources without negatively affecting it. The beneficiary role of blue-green algae (BGA) by way of supporting the nitrogen economy of paddy fields and enhancing rice productivity is well documented. The simple presence of BGA in soil results in formation of soil aggregates, which reduces soil loss during rainy season and regulates aeration, soil temperature, hence, improving physical and chemical properties of soil vis-a-vis physical environment of the crop. BGA are helpful in restoring soil nutrients by secreting exopolysaccharides and bioactive substances. They have the potential to mobilize insoluble forms of inorganic phosphates. Algalization has been employed for reducing the amount of exchangeable sodium, which results in altered soil pH and leads to reclamation of sodic soils. Some red algae used as biofertilizers have been found to augment growth nutritional value and yield of crop plants. This chapter provides an overview of the role of algae as biofertilizers.

Overexpression of AhpC enhances stress tolerance and N2-fixation in Anabaena by upregulating stress responsive genes.

Abstract Cyanobacteria due to their remarkable evolutionary advances such as the presence of oxygenic photosynthesis have been considered as an ideal system for plant-based studies in order to assess fundamental biochemical processes like carbon and nitrogen assimilation and photosynthesis processes. Moreover, the exclusive ability of both photosynthesis and nitrogen fixation together with adaptability to various environmental fluctuations of few genera makes them ubiquitous. Cyanobacterial genes involved in carbon metabolism, fatty acid biosynthesis, and pigment biosynthesis have been exploited as substitute for homologous gene sources, targeting enhanced plant productivity and nutritional values. Present chapter sheds light on key contributions of cyanobacterial biodiversity and biotechnology along with the future prospects for developing transgenic crops of high yield and nutritive value utilizing cyanobacterial genes.

Alr2954 of Anabaena sp. PCC 7120 with ADP-ribose pyrophosphatase activity bestows abiotic stress tolerance in Escherichia coli.

Improved processing quality is an important objective of wheat breeding which is largely associated with the amount and composition of endosperm seed proteins in the wheat kernel. Especially, HMW-GS determines dough strength and visco-elasticity contributing towards end-use product. Glu-B1 is the candidate structural gene, coding for Glu1Bx and associated with the quantity of high-molecular-weight (HMW) glutenin in bread wheat. This study provides detection of GluB-1 alleles on 19 different wheat cultivars by precise AS-PCR marker with the aim to develop marker for HMW-GS 1Bx20 which is assumed to be associated with chapatti making quality (CMQ) in bread wheat. The primer pair gave diagnostic banding pattern in different varieties with 1Bx7, 1Bx20 and 1Bx17+18 GluB-1 alleles. The result of this study will help in detection of varieties with different allelic combinations at their GluB-1 loci in early developmental stage using single marker which reduces the time for varietal selection. It will be also useful in screening of wheat cultivars with good chapatti making quality and introgression of subunit 1Bx20 in high yielding varieties using marker-assisted selection (MAS).