Indian Agricultural Statistics Research Institute

About: Indian Agricultural Statistics Research Institute is a facility organization based out in New Delhi, India. It is known for research contribution in the topics: Population & Small area estimation. The organization has 454 authors who have published 870 publications receiving 7987 citations.

Complexation of DTPA and EDTA with Cd2+: stability constants and thermodynamic parameters at the soil-water interface

Abstract: Two alkaline soils collected from the surface horizon (0–15 cm) of two agricultural fields Lakshmikantapur (LKP; 22° 06′ 03″ N and 88° 18′ 19″ E) and Diamond Harbour (DHB; 22° 11′ N and 88° 14′ E) of West Bengal, India were studied to observe the stability of cadmium (Cd) chelate complexes with diethylenetriaminepentaacetatic acid (DTPA) and ethylenediaminetetraacetic acid (EDTA), removing organic matter (OM). The objective of the present study is “determination of the stability constants and the thermodynamic parameters of Cd-DTPA and Cd-EDTA complexes at different pH and temperatures at the soil-water interface”. Complex formation of soil Cd with DTPA and EDTA at the soil-water interface was studied under different ligand-to-metal ratios, pHs and temperatures. Apparent conditional stability constants (log k´) were calculated from the concentrations of Cd chelates and free Cd2+, estimated by solid phase extraction with an ion exchanger. Standard Gibbs energy (ΔG°), standard enthalpy (ΔH°) and standard entropy (ΔS°) of formation were calculated at three different temperatures. The higher stability constants of Cd-DTPA than Cd-EDTA indicated longer persistence of Cd-DTPA at the soil solution interface than Cd-EDTA complex. Increase of ΔG°, ΔH° and ΔS° with progress of temperature revealed that Cd-complex formation was facilitated by temperature. Highly negative ΔG° and positive ΔH° for Cd-complex formation indicated the reaction spontaneous and exothermic. In general, both ligands complexed high percentages of cadmium signalling their role in enhancing remobilization of Cd present in soil and preventing exchange of contaminated Cd from external source with soil mineral matrix; these phenomena may greatly reduce hazard for environment and human health. The result of this study support that DTPA increases solubility and more persistence of Cd in acidic soils within the range of temperature and mole fraction (MF = moles of Cd2+ / sum of the moles of Cd2+ and chelating agent) than that of EDTA due to higher capability of complex formation with Cd2+. Therefore, DTPA enhanced Cd toxicity in acid soils and groundwater. Complex formation in the presence of DTPA at acidic pH decreases with temperature and increases with pH. The higher per cent of Cd complexed in the presence of DTPA revealed that DTPA is a stronger chelating agent than EDTA at acidic pHs. Whereas, the capability of complex formation by EDTA is lower at lower pH but higher at higher pH.

Functional profiling of cyanobacterial genomes and its role in ecological adaptations

Abstract: With the availability of complete genome sequences of many cyanobacterial species, it is becoming feasible to study the broad prospective of the environmental adaptation and the overall changes at transcriptional and translational level in these organisms. In the evolutionary phase, niche-specific competitive forces have resulted in specific features of the cyanobacterial genomes. In this study, functional composition of the 84 different cyanobacterial genomes and their adaptations to different environments was examined by identifying the genomic composition for specific cellular processes, which reflect their genomic functional profile and ecological adaptation. It was identified that among cyanobacterial genomes, metabolic genes have major share over other categories and differentiation of genomic functional profile was observed for the species inhabiting different habitats. The cyanobacteria of freshwater and other habitats accumulate large number of poorly characterized genes. Strain specific functions were also reported in many cyanobacterial members, of which an important feature was the occurrence of phage-related sequences. From this study, it can be speculated that habitat is one of the major factors in giving the shape of functional composition of cyanobacterial genomes towards their ecological adaptations.

Putative Microsatellite DNA Marker-Based Wheat Genomic Resource for Varietal Improvement and Management.

Abstract: Wheat fulfills 20% of global caloric requirement. World needs 60% more wheat for 9 billion population by 2050 but climate change with increasing temperature is projected to affect wheat productivity adversely. Trait improvement and management of wheat germplasm requires genomic resource. Simple Sequence Repeats (SSRs) being highly polymorphic and ubiquitously distributed in the genome, can be a marker of choice but there is no structured marker database with options to generate primer pairs for genotyping on desired chromosome/physical location. Previously associated markers with different wheat trait are also not available in any database. Limitations of in vitro SSR discovery can be overcome by genome-wide in silico mining of SSR. Triticum aestivum SSR database (TaSSRDb) is an integrated online database with three-tier architecture, developed using PHP and MySQL and accessible at http://webtom.cabgrid.res.in/wheatssr/. For genotyping, Primer3 standalone code computes primers on user request. Chromosome-wise SSR calling for all the three sub genomes along with choice of motif types is provided in addition to the primer generation for desired marker. We report here a database of highest number of SSRs (476,169) from complex, hexaploid wheat genome (~17 GB) along with previously reported 268 SSR markers associated with 11 traits. Highest (116.93 SSRs/Mb) and lowest (74.57 SSRs/Mb) SSR densities were found on 2D and 3A chromosome, respectively. To obtain homozygous locus, e-PCR was done. Such 30 loci were randomly selected for PCR validation in panel of 18 wheat Advance Varietal Trial (AVT) lines. TaSSRDb can be a valuable genomic resource tool for linkage mapping, gene/QTL (Quantitative trait locus) discovery, diversity analysis, traceability and variety identification. Varietal specific profiling and differentiation can supplement DUS (Distinctiveness, Uniformity, and Stability) testing, EDV (Essentially Derived Variety)/IV (Initial Variety) disputes, seed purity and hybrid wheat testing. All these are required in germplasm management as well as also in the endeavor of wheat productivity.

Comparative Transcriptome Analysis of Iron and Zinc Deficiency in Maize ( Zea mays L.)

Abstract: Globally, one-third of the population is affected by iron (Fe) and zinc (Zn) deficiency, which is severe in developing and underdeveloped countries where cereal-based diets predominate. The genetic biofortification approach is the most sustainable and one of the cost-effective ways to address Fe and Zn malnutrition. Maize is a major source of nutrition in sub-Saharan Africa, South Asia and Latin America. Understanding systems' biology and the identification of genes involved in Fe and Zn homeostasis facilitate the development of Fe- and Zn-enriched maize. We conducted a genome-wide transcriptome assay in maize inbred SKV616, under -Zn, -Fe and -Fe-Zn stresses. The results revealed the differential expression of several genes related to the mugineic acid pathway, metal transporters, photosynthesis, phytohormone and carbohydrate metabolism. We report here Fe and Zn deficiency-mediated changes in the transcriptome, root length, stomatal conductance, transpiration rate and reduced rate of photosynthesis. Furthermore, the presence of multiple regulatory elements and/or the co-factor nature of Fe and Zn in enzymes indicate their association with the differential expression and opposite regulation of several key gene(s). The differentially expressed candidate genes in the present investigation would help in breeding for Fe and Zn efficient and kernel Fe- and Zn-rich maize cultivars through gene editing, transgenics and molecular breeding.

Minimal balanced repeated measurements designs

Abstract: Experimental designs in which treatments are applied to the experimental units, one at a time, in sequences over a number of periods, have been used in several scientific investigations and are known as repeated measurements designs. Besides direct effects, these designs allow estimation of residual effects of treatments along with adjustment for them. Assuming the existence of first-order residual effects of treatments, Hedayat & Afsarinejad (1975) gave a method of constructing minimal balanced repeated measurements [RM(v,n,p)] design for v treatments using n=2v experimental units for p [=(v+1)/2] periods when v is a prime or prime power. Here, a general method of construction of these designs for all odd v has been given along with an outline for their analysis. In terms of variances of estimated elementary contrasts between treatment effects (direct and residual), these designs are seen to be partially variance balanced based on the circular association scheme.