Linkage mapping of QTLs for grain minerals (iron and zinc) and physio-morphological traits for development of mineral rich rice (Oryza sativa L.)

69-80In the present investigation, experiments were conducted to evaluate F3 and F4 populations derived from cross between PAU201 (high-yield) and Palman 579 (iron-rich) indica rice varieties for various physio-morphological traits and minerals (iron and zinc) content. Phenotypic correlation analysis showed no correlation between grain iron and zinc content in F3 and F4 population (s). A DNA fingerprint database of 33 PAU201 × Palman 579 derived F4 plants was prepared using 61 polymorphic SSR markers distributed on the entire genome of rice. The results of NTSYS-pc UPGMA tree cluster analysis and two and three dimensional principal component analysis (PCA) scaling showed scattering of the F4 population between the two distinct parent genotypes; but more inclined towards Palman 579. The SSR data was used to identify quantitative trait loci (QTL) for grain mineral content and physio-morphological traits. A total of 128 alleles and three new recombinant alleles were identified in F4 plants population. Composite interval mapping (CIM) analysis by WinQTL cartographer 2.5 revealed a total of six QTLs for mineral content (five for iron and one for zinc) in rice grains on chromosome 5, 6, 7, 9 and sixteen QTLs for various physio-morphological traits on chromosomes 2, 5, 7, 8, 9, 10 and 12. Linkage mapping of QTLs of minerals (iron and zinc) can greatly enhance the efficacy of breeding programs to improve mineral density in rice. The QTLs for minerals identified can successfully employed to improve the target traits through marker assisted selection

Genetic variation, linkage mapping of QTL and correlation studies for yield, root, and agronomic traits for aerobic adaptation

BACKGROUND: Water scarcity and drought have seriously threatened traditional rice cultivation practices in several parts of the world, including India. Aerobic rice that uses significantly less water than traditional flooded systems has emerged as a promising water-saving technology. The identification of QTL conferring improved aerobic adaptation may facilitate the development of high-yielding aerobic rice varieties. In this study, experiments were conducted for mapping QTL for yield, root-related traits, and agronomic traits under aerobic conditions using HKR47 × MAS26 and MASARB25 × Pusa Basmati 1460 F(2:3) mapping populations. RESULTS: A total of 35 QTL associated with 14 traits were mapped on chromosomes 1, 2, 5, 6, 8, 9, and 11 in MASARB25 x Pusa Basmati 1460 and 14 QTL associated with 9 traits were mapped on chromosomes 1, 2, 8, 9, 10, 11, and 12 in HKR47 × MAS26. Two QTL (qGY(8.1) with an R(2) value of 34.0% and qGY(2.1) with an R(2) value of 22.8%) and one QTL (qGY(2.2) with an R(2) value of 43.2%) were identified for grain yield under aerobic conditions in the mapping populations MASARB25 × Pusa Basmati 1460 and HKR47 × MAS26, respectively. A number of breeding lines with higher yield per plant, root length, dry biomass, length-breadth ratio, and with Pusa Basmati 1460-specific alleles in a homozygous or heterozygous condition at the BAD2 locus were identified that will serve as novel material for the selection of stable aerobic Basmati rice breeding lines. CONCLUSIONS: Our results identified positive correlation between some of the root traits and yield under aerobic conditions, indicating the role of root traits for improving yield under aerobic situations possibly through improved water and nutrient uptake. Co-localization of QTL for yield, root traits, and yield-related agronomic traits indicates that the identified QTL may be immediately exploited in marker-assisted-breeding to develop novel high-yielding aerobic rice varieties

Melanotic medullary carcinoma of thyroid – report of a rare case with brief review of literature

<p>Abstract</p> <p>Background</p> <p>Melanin production in medullary carcinoma is extremely uncommon.</p> <p>Case presentation</p> <p>We report a rare variant of medullary carcinoma of thyroid with melanin production in a 52-year-old woman who presented with swelling in the thyroid of 3 months duration. This tumor recurred thrice in two years after surgery and patient died with metastasis. Microscopic examination showed typical morphology of medullary carcinoma with numerous cells loaded with melanin pigment as confirmed by bleached Fontana-Masson, negative iron and immunohistochemical stains. Tumor cells were diffusely immunopositive for calcitonin, HMB-45, chromogranin, synaptophysin, CEA but showed focal paranuclear dot positivity for cytokeratin. No C-cell hyperplasia was seen in the adjacent thyroid gland. Nature of the pigment was further confirmed on ultra structural examination.</p> <p>Conclusion</p> <p>Melanotic medullary carcinoma is an extremely uncommon entity. There is a need to report more number of cases in the literature for exact categorization and prognostication of this subtype of medullary carcinoma.</p

Phenotyping, microsatellite marker analysis and linkage mapping of QTL for agronomic and root traits using IB370 × MAS-ARB25 F2 rice (Oryza sativa L.) population grown under aerobic conditions

91-100Expanding water shortage, environmental change and decline water table level are the major hindrance for lowland basmati rice variety development in northern parts of India including Haryana. Rice is the absolute most client of fresh irrigated water as it devours 70% of the complete water accessible. More rice is needed to generate to take care of the expanding populace. The promising way to deal with battle the water shortage can be aerobic rice. Aerobic rice is a budding cultivation system that requires no puddling, no transplanting and without need of frequent irrigation than conventional flooded rice. The worth of basmati rice breeding can significantly improve through marker assisted selection (MAS). In the present study, experiments were conducted to assess F2 generation obtained from IB370 × MAS-ARB25 for various agronomic qualities. Grain yield/plant indicated impressive positive relationship (r = 0.25) with root thickness in F2 population. Fifty eight polymorphic SSR markers dispersed on the entire genome of rice were utilized for planning DNA fingerprint data set of the isolating IB370 × MAS-ARB25 F2 population. Composite interval mapping analysis by WinQTL cartographer version 2.5 revealed a sum of 7 quantitative trait loci (QTLs) (three QTL for agronomic traits and four for root traits). The selected promising F2 plants were additionally checked for these putative QTLs recognized in the F2 populace, which were available in homozygous/heterozygous state in high frequencies

Molecular Strategies for Developing Salt Tolerant Crops

121-137Salinity is one of the most important abiotic stresses for agricultural crops. High concentrations of salts cause hyperosmotic and ionic stresses, which, in turn, may generate secondary stresses such as oxidative stress, etc. The complexity and polygenic nature of salt tolerance trait has seriously limited the efforts to develop salt-tolerant crop varieties. This paper reviews new molecular strategies that have been or can be used for the molecular dissection of plant responses to salt stress, discovery of novel structural and regulatory genes involved in stress adaptation, and transgenic and molecular marker strategies used for engineering salt tolerance in plants. Application of novel techniques such as genome sequencing, high-throughput analysis of genomic-scale expressed sequence tags (ESTs), DNA chips/cDNA microarray analyses, targeted or random mutagenesis, knockouts, molecular mapping and gain-of-function or mutant complementation, is expected to accelerate the discovery of the new genes involved in stress adaptation as well as improve understanding of stress biology. A number of stress-related genes have been characterized including the ones that encode for important enzymes or a biochemical pathway, participate in signaling pathways or act as transcriptional regulators for coordinated regulation of stress related genes. Some of these genes have been successfully transferred in model plant species including Arabidopsis, rice and tobacco, and a marginal to significant improvement in salt-tolerance has been reported. In addition, molecular markers can be used for linkage mapping of genes/QTLs for salinity tolerance trait, marker-assisted transfer and pyramiding of such QTLs into agronomically desirable genotypes and/or for map-based cloning of genes. Application of transgenic and molecular marker research coupled with rapid gene discovery via functional genomic research in plants shall provide effective means for designing salt-tolerant crops.</span

Molecular strategies for developing salt tolerant crops

Salinity is one of the most important abiotic stresses for agricultural crops. High concentrations of salts cause hyperosmotic and ionic stresses, which, in turn, may generate secondary stresses such as oxidative stress, etc. The complexity and polygenic nature of salt tolerance trait has seriously limited the efforts to develop salt-tolerant crop varieties. This paper reviews new molecular strategies that have been or can be used for the molecular dissection of plant responses to salt stress, discovery of novel structural and regulatory genes involved in stress adaptation, and transgenic and molecular marker strategies used for engineering salt tolerance in plants. Application of novel techniques such as genome sequencing, high-throughput analysis of genomic-scale expressed sequence tags (ESTs), DNA chips/cDNA microarray analyses, targeted or random mutagenesis, knockouts, molecular mapping and gain-of-function or mutant complementation, is expected to accelerate the discovery of the new genes involved in stress adaptation as well as improve understanding of stress biology. A number of stress-related genes have been characterized including the ones that encode for important enzymes or a biochemical pathway, participate in signaling pathways or act as transcriptional regulators for coordinated regulation of stress related genes. Some of these genes have been successfully transferred in model plant species including Arabidopsis, rice and tobacco, and a marginal to significant improvement in salt-tolerance has been reported. In addition, molecular markers can be used for linkage mapping of genes/QTLs for salinity tolerance trait, marker-assisted transfer and pyramiding of such QTLs into agronomically desirable genotypes and/or for map-based cloning of genes. Application of transgenic and molecular marker research coupled with rapid gene discovery via functional genomic research in plants shall provide effective means for designing salt-tolerant crops

An encyclopedia of mouse DNA elements (Mouse ENCODE)

To complement the human Encyclopedia of DNA Elements (ENCODE) project and to enable a broad range of mouse genomics efforts, the Mouse ENCODE Consortium is applying the same experimental pipelines developed for human ENCODE to annotate the mouse genome