Deployment of wild relatives for genetic improvement in rice (Oryza sativa)

Rice is one of the most important crops in the world. The wild species of rice are expected to have novel beneficial alleles that have been lost from cultivated rice during the process of domestication. Therefore, wild species could be the potential source to induce lost genetic diversity in cultivated rice. Serving as an important reservoir of novel genes/QTLs, wild species, in general, are better adapted to different ecologies and can tolerate many biotic and abiotic stresses. Despite that, only a few wild species are studied and extensive characterization both at the molecular and morphological level is yet to be achieved. Several agronomically important genes/QTLs for improving biotic and abiotic stresses, resistance, productivity and grain quality traits were identified from AA genome donor wild species and were tagged with breeder friendly molecular markers for their transfer to elite genetic backgrounds. The present review provides information on the important wild rice species harbouring genes/QTLs for agriculturally important traits and their successful utilization in rice breeding programmes.     

Shrimp Oil Extracted from Shrimp Processing By-Product Is a Rich Source of Omega-3 Fatty Acids and Astaxanthin-Esters,and Reveals Potential Anti-Adipogenic Effects in 3T3-L1 Adipocytes

The province of Newfoundland and Labrador, Canada, generates tons of shrimp processing by-product every year. Shrimp contains omega (n)-3 polyunsaturated fatty acids (PUFA) and astaxanthin (Astx), a potent antioxidant that exists in either free or esterified form (Astx-E). In this study, shrimp oil (SO) was extracted from the shrimp processing by-product using the Soxhlet method (hexane:acetone 2:3). The extracted SO was rich in phospholipids, n-3 PUFA, and Astx-E. The 3T3-L1 preadipocytes were differentiated to mature adipocytes in the presence or absence of various treatments for 8 days. The effects of SO were then investigated on fat accumulation, and the mRNA expression of genes involved in adipogenesis and lipogenesis in 3T3-L1 cells. The effects of fish oil (FO), in combination with Astx-E, on fat accumulation, and the mRNA expression of genes involved in adipogenesis and lipogenesis were also investigated. The SO decreased fat accumulation, compared to untreated cells, which coincided with lower mRNA expression of adipogenic and lipogenic genes. However, FO and FO + Astx-E increased fat accumulation, along with increased mRNA expression of adipogenic and lipogenic genes, and glucose transporter type 4 (Glut-4), compared to untreated cells. These findings have demonstrated that the SO is a rich source of n-3 PUFA and Astx-E, and has the potential to elicit anti-adipogenic effects. Moreover, the SO and FO appear to regulate adipogenesis and lipogenesis via independent pathways in 3T3-L1 cells.     

Hepatorenal repercussions of alcoholic exposure in a rat model: a dose-dependent study of metformin intervention

Background: Diabetes mellitus is an alarming life style disease in the modern world. Exploitation of the anti-diabetic drugs for the amelioration of diabetes and associated life style diseases has become an imperative concern. In this milieu, this study was designed to explore the plausible effects of metformin intervention on hepatic and renal functions in a rat model of alcoholic liver disease. Methods: Thirty rats were divided into five groups (n = 6): ethanol control, ethanol water and also low, moderate and high doses of metformin. Ethanol 20% v/v (1 ml/100 g) was administered by oral gavage to all five groups for 21 days. Blood and tissue samples were collected for the assessment of lipid profile, hepatic and renal functions. Results: After 21 days, the levels of hepatic function and lipid parameters were maintained at normalcy, especially in the high-dose metformin treated alcoholic rats as compared to the levels at day 1. Despite this, the renal biomarkers did not display any significant variation due to ethanolic exposure in any group. The histopathological score portrayed that the noxious effect of ethanol is prevented in the liver of moderate- and high-dose metformin, whereas the renal histological scores were unchanged in all the groups including ethanol control. Conclusion: These results suggest that the dose of ethanol required to induce hepatic dysfunction does not influence renal functions. In addition, high-dose metformin offers maximal hepatoprotection and spares kidney from per se toxicity, thereby advocating the beneficial intervention of the anti-diabetic drug, metformin, in alcoholic liver dysfunction. Key Words: Ethanol, Metformin, Kidney     

Crop performance in permanent raised bed rice–wheat cropping system in Punjab,India

Raised beds are widely used in agriculture in developed countries and have proven to be an excellent option for wheat. Permanent raised beds may also offer benefits for rice–wheat (RW) systems in South Asia, in terms of both production and the possibility that furrow-irrigation may be more efficient than flood irrigation. The performance of a RW system on permanent raised beds (37 cm wide, 15 cm high, furrow width 30 cm) was compared with conventional cultivation on the flat on sandy loam and loam soils in replicated experiments in central Punjab, India. The experiments commenced with wheat sown in November 2002, and were continued for 8 crops.     

Beneficial elements for agricultural crops and their functional relevance in defence against stresses

The beneficial elements are not deemed essential for all crops but may be vital for particular plant taxa. The distinction between beneficial and essential is often difficult in the case of some trace elements. Elements such as aluminium (Al), cobalt (Co), sodium (Na), selenium (Se) and silicon (Si) are considered beneficial for plants. These elements are not critical for all plants but may improve plant growth and yield. Pertinently, beneficial elements reportedly enhance resistance to abiotic stresses (drought, salinity, high temperature, cold, UV stress, and nutrient toxicity or deficiency) and biotic stresses (pathogens and herbivores) at their low levels. However, the essential-to-lethal range for these elements is somewhat narrow. The effect of beneficial elements at low levels deserves more attention with regard to using them to fertilize crops to boost crop production under stress and to enhance plant nutritional value as a feed or food. A more holistic approach to plant nutrition would not only be restricted to nutrients essential to survival but would also include mineral elements at levels beneficial for best growth. Here, we describe the uptake mechanisms of various beneficial elements, their favourable aspects, and the role of these elements in conferring tolerance against abiotic and biotic stresses.     

Progression of molecular and phenotypic diversification in resynthesized Brassica juncea (L) gene pool with determinate inflorescence

Indian mustard (Brassica juncea (L) Czern & Coss) is naturally indeterminate. Plants with determinate inflorescence were first discovered in the self progenies of B. juncea (AABB; 2n = 36), resynthesized by combining A-genome from B. napus (AACC; 2n = 38) and B-genome from B. carinata (BBCC; 2n = 34). In the determinate plants, apical meristems were transformed into pods. In contrast, the inflorescence in the indeterminate plants continues to grow indefinitely while producing peripheral flowers. Genotyping and morphological characterization of newly developed determinate gene pool (A₈) showed a rapid emergence and progression of genetic and phenotypic alterations which continued even after seven generations of selfing. A large number of determinate genotypes (125) were evaluated to establish agronomic potential of determinate B. juncea. A high proportion of determinate genotypes outperformed the best indeterminate checks, suggesting that critical productivity related traits like pod number, seed size and oil content were not a function of indeterminacy. As the gene for determinacy has also been introgressed in B. napus and B. carinata, the stage is now set for future breeding to aim at crop architectural modifications through determinacy in all three types of oilseed Brassicas grown in the world. Our studies emphasized the role of polyploidy as a major force of differentiation at both genotypic and phenotypic level. Although, there was no direct correlation between evolution of genetic and phenotypic diversities following polyploidization. We suggest the use of polyploidy as a plant breeding tool to benefit from de novo variation rather than restricting its use as a method to overcome sterility following wide hybridization alone.     

Effects of dietary supplements of selenium, vitamin E or combinations of the two on antibody responses of broilers

1. The effects of selenium and vitamin E supplementation on some immune parameters were investigated in broilers. 2. Broiler chicks were fed on maize-soybean diets with different concentrations of vitamin E (0-200 mg/kg) and selenium (0-0.2 mg/kg diet) either alone or in combinations from 1 to 42 d of age. 3. Chicks were immunised against Newcastle disease virus (NDV) vaccine at 21 d of age and haemagglutination inhibition (HI) titres were determined after 10 d. 4. Chicks receiving supplements of 200 mg vitamin E/kg and 0.2 mg selenium/kg produced significantly higher HI antibody titres. This was associated with an increased serum concentration of total immunoglobulins and circulatory immune complexes. 5. The chicks given 200 mg vitamin E/kg and 0.2 mg selenium/kg had significantly heavier spleen and bursa. 6. These results suggested that vitamin E and selenium have synergistic effects on immune responses.