Photosystem II and cellular membrane stability evaluation in hexaploid wheat seedlings under salt stress conditions

Salinity limits crop production in large areas of the world. The application of in vitro Photosystem II (PS‐II) activity measurements to screen hexaploid wheat (Triticum aestivum, L.) genotypes for NaCl tolerance has been investigated by comparing their responses under stress and control (no added NaCl) conditions. One of the four cultivars used in the study was ‘Kharchia’ known for its high salt tolerance. Wheat seedlings were grown hydroponically in environmental chambers and treated with a range of NaCl concentrations (0.034 M, 0.17 M, 0.68 M, or 3.42 M) over a 1, 3, and 5‐day period. The salt treatments were started in the appropriate time so that they were all ten‐day‐old during harvest. Cellular membrane stability (CMS) as measured by a conductivity method and PS‐II activity values were affected adversely by NaCl concentration and duration of treatment. Both methods clearly distinguish between salt‐sensitive and salt‐tolerant genotypes. Statistical analysis showed that PS‐II activity and CMS measurements are well correlated (r=0.7589) suggesting that PS‐II activity would be used as an additional screening method besides CMS to evaluate salt tolerance of wheat.     

Biocontrol efficiency of Fusarium wilt diseases by a root-colonizing fungus Penicillium sp.

Soil-inhabiting fungal pathogen Fusarium oxysporum often causes severe yield losses in many crops. We investigated the effect of a plant growth-promoting fungus, Penicillium sp. EU0013 on Fusarium wilt disease. In dual culture experiments, EU0013 inhibited the growth of Fusarium wilt pathogens by producing an inhibition zone. In experiments using sterile potting medium under controlled conditions, EU0013 significantly reduced the severity of Fusarium wilt on tomato (Solanum lycopersicum L.) and cabbage (Brassica oleracea L. var. capitata). In non-sterile soil, benomyl-resistant mutants of EU0013 were selected by exposing the conidial solution of EU0013 to ultraviolet light. The selected mutant EU0013_90S isolate did not show any distinct differences from EU0013 in colony characteristics, growth rate or antifungal activity against Fusarium wilt pathogens in dual culture. The effect of EU0013_90S on tomato wilt was studied under greenhouse conditions using non-sterile soil. Two-weeks old tomato seedlings were dipped in four different concentrations of EU0013_90S conidial suspension (1?×?10³, 1?×?10⁴, 1?×?10⁵, and 1?×?10⁶ conidia mL^–1). Seedlings were then planted in soil inoculated with either F. oxysporum f. sp. lycopersici race 1 CU1 or race 2 JCM 12575 (1?×?10⁶ bud-cells g^–1). We found the greatest disease suppression occurred when seedlings were dipped in the highest concentration of EU0013_90S conidia. This same inoculum concentration of EU0013_90S also resulted in the highest disease reduction in soil infested with JCM 12575. Higher root colonization with EU0013_90S showed a significant reduction in Fusarium wilt disease, suggesting that colonization by Penicillium sp. EU0013_90S is important for efficient biocontrol of these diseases.     

A Simple PCR Procedure to Detect White Spot Syndrome Virus (WSSV) of Shrimp, <Emphasis Type="Italic">Penaeus monodon</Emphasis> (Fabricious)

A non-stop, single tube and semi-nested polymerase chain reaction (PCR) technique with simple procedure was developed for simultaneous detection and grading the level of white spot syndrome infection in penaeid shrimp, Penaeus monodon. In this PCR procedure, three sense primers and one antisense primer with uniform annealing temperature of 55 °C were used. These primers amplify three PCR products (500, 300 and 200 base pairs [bp]) depending upon the severity of infection. Quantities of WSSV-DNA at 10 pg and greater gave three PCR products of 500, 300, 200 bp. A moderate concentration of WSSV-DNA, around 100 fg, gave two products of 300 and 200 bp and a low concentration of 1 fg or more gave only one PCR product of 200 bp. This PCR technique was assessed for early detection of WSSV in shrimp. In time-course infectivity experiments conducted on shrimp with WSSV, one PCR product (200 bp) was seen in hemolymph, tail tissue and gill at 3 h post infection (p.i.); two PCR products (300 and 200 bp) were seen in tail tissue, hemolymph, heart tissue and gill at 18 h p.i. At 30 h p.i., three PCR products (500, 300, 200 bp) were seen in all the organs tested. The samples collected from control animals showed negative for WSSV.     

Iron Uptake and Loading into Rice Grains

Iron (Fe) is an important micronutrient for living organisms. Fe deficiency severely impairs plant growth and is a widespread human dietary problem, with particularly high numbers of affected children and females. Rice (Oryza sativa) is a source of energy for more than half of the world’s population. Thus, understanding the mechanisms of Fe uptake and translocation in rice is of utmost importance in the development of rice varieties that are tolerant to low Fe availability and with high seed levels of Fe. In recent years, the mechanisms underlying Fe transport and homeostasis have been revealed, providing opportunities to increase the Fe content of rice grain. As excess Fe is toxic to cells, plants have developed sophisticated mechanisms to control Fe flow, making it difficult to alter Fe transport. Thus, choosing appropriate chelators and Fe transporters driven by appropriate promoters seems to be the key in developing rice that is tolerant to low Fe availability and which accumulates high grain levels of Fe. Many recent studies have been aimed at increasing the Fe content of rice. Here, we summarize these efforts and review recent progress in understanding the mechanisms of Fe transport.     

Hexane Extract of Raphanus sativus L. Roots Inhibits Cell Proliferation and Induces Apoptosis in Human Cancer Cells by Modulating Genes Related to Apoptotic Pathway

Raphanus sativus, a common cruciferous vegetable has been attributed to possess a number of pharmacological and therapeutic properties. It has been used in indigenous system of medicine for the treatment of various human ailments in India. This present study evaluated the chemopreventive efficacy of different parts of R. sativus such as root, stem and leaves, extracted with solvents of varying polarity and investigated the molecular mechanism leading to growth arrest and apoptotic cell death in human cancer cell lines. Of the different parts, significant growth inhibitory effect was observed with hexane extract of R. sativus root. Analysis of hexane extract by GC-MS revealed the presence of several isothiocyanates (ITCs) such as 4-(methylthio)-3-butenyl isothiocyanate (MTBITC), 4-(methylthio)-3-butyl isothiocyanate (erucin), 4-methylpentyl isothiocyanate, 4-pentenyl isothiocyanate and sulforaphene. R. sativus root extract induced cell death both in p53 proficient and p53 deficient cell lines through induction of apoptotic signaling pathway regardless of the p53 status of cells. The molecular mechanisms underlying R. sativus-induced apoptosis may involve interactions among Bcl₂ family genes, as evidenced by up-regulation of pro-apoptotic genes and down-regulation of anti-apoptotic genes along with activation of Caspase-3. Our findings present the first evidence that hexane extract of R. sativus root exerts potential chemopreventive efficacy and induces apoptosis in cancer cell lines through modulation of genes involved in apoptotic signaling pathway.     

Evaluation of the effects induced by dietary diphenyl diselenide on common carp Cyprinus carpio

Several diets employed in aquaculture are enriched with selenium (Se), as it is a fundamental element to aquatic vertebrates. Diphenyl diselenide [(PhSe)₂], which is a synthetic organoselenium compound, has been considered a potential antioxidant agent in different experimental models. Thus, the aim of this study was to evaluate the effects of dietary diphenyl diselenide at concentrations of 1.5, 3.0, and 5.0 mg/kg for 60 days and to determine its optimal supplemental level for carp, Cyprinus carpio. Neither growth retardation nor hepatoxicity was induced by the inclusion of diphenyl diselenide at concentrations ranging from 1.5 to 5.0 mg/kg. In addition, the inclusion of 3.0 mg/kg of diphenyl diselenide stimulated the weight and length of the carp. The supplementation with 1.5 and 3.0 mg/kg of diphenyl diselenide did not produce oxidative damage in the tissues, verified by peroxidation lipid and protein carbonyl assays. However, at 5.0 mg/kg, it caused an increase of the lipid peroxidation in the liver, brain, and muscle, and inhibited the cerebral acetylcholinesterase activity. An increase of the hepatic superoxide dismutase activity and non-protein thiols content in all tissues and ascorbic acid in the liver, gills, and brain was verified in carp fed with the diet containing 3.0 mg/kg of diphenyl diselenide. This diet had advantageous effects for the fish used in experiments. Therefore, this compound could be considered a beneficial dietary supplement for carp nutrition.     

Tree Culture of Smallholder Farmers Practicing Agroforestry in Gunung Salak Valley,West Java,Indonesia

This paper investigates the types of agroforestry system that exist in Gunung Salak Valley, West Java, Indonesia in order to characterize the differences in their basic structure and associated crop plant diversity. Data were collected through rapid rural appraisal, field observation and focus groups, followed by household survey of a sample of 20 agroforestry farmers. Five main agroforestry systems (homegardens, fruit tree system, timber tree system, mixed fruit–timber system, and cropping in the forest understory) exist in the study area, and all of them exhibit a noticeable diversity in terms of both species composition and utilization. Products from farming accounted for an average 24 % of household income. They comprised agroforestry products which contributed IDR 3.25 million/year and other agricultural products contributing IDR 1.66 million/year. The observed agroforestry systems include not only a form of forest dominated by ‘cultivated trees’, but also an anthropogenic vegetation formation derived from agricultural antecedents. In land-use classifications agroforestry systems are not recognized as forestry, but like forests they provide tree products and services. Classification will always be disfunctional if a binary system is applied, thus a more sophisticated approach should be adopted that incorporates the economic and environmental characteristics of a wider range of systems.     

Development of breeding populations from interspecific hybrids between Trifolium repens L. and T. occidentale Coombe

Trifolium occidentale is a diploid wild relative of T. repens (white clover) with adaptation to dry, saline coastal habitats. Transfer of drought and salt‐tolerant adaptive traits to white clover could be potentially valuable if interspecific hybridization can be achieved efficiently and leads to fertile hybrid populations. To achieve hybridization, 4x plants of T. occidentale were generated. Efficient techniques for generation of 4x plants and their identification using dry pollen shape are described. Interspecific 4x F₁ plants were achieved without embryo rescue. F₂ populations and first backcross hybrids to white clover were also efficiently achieved. Although male and female fertility were lower than in white clover, they were adequate to produce large amounts of seed from small numbers of inflorescences. Thus, early generation interspecific hybrid prebreeding populations can be readily developed, opening the way for transfer of traits from T. occidentale to white clover.