Identification of Physiological Traits Underlying Cultivar Differences in Drought Tolerance in Rice and Wheat

Rice is used as a model cereal to study drought response at the molecular level, with the goal of applying results to other cereals. To assess the relevance of results from rice to other species, the kinetics of drought development and plant response of tolerant and susceptible tropical rice ( Oryza sativa L.) and subtropical wheat ( Triticum aestivum L.) cultivars were compared under vegetative and reproductive stage drought in pot experiments. Water was withheld during reproductive stage until plant available soil moisture content was 30 % of field capacity (FC) or leaf wilting was observed, and then reapplied. Rice reached 30 % FC 9 days after withholding water and wheat after 13 days. Before rewatering, both species reached leaf water potentials of −12 bars and similarly low transpiration rates. Stress reduced leaf relative water content, leaf elongation and membrane stability. When water stress was imposed during reproductive stage, pollen fertility was most affected in wheat, while panicle exsertion and anther dehiscence were severely affected in rice. When water stress was imposed during vegetative stage, wheat was less affected to vegetative stage drought than rice. The nature of differences between tolerant and susceptible cultivars was similar for the two species. However, the differential growth habitats and growth rate of plants needs to be considered in these kinds of experiments.     

A study on the influence of selected Indian herbal active principles on enhancing the immune system in Fenneropenaeus indicus against Vibrio harveyi infection

Five herbs such as Acalypha indica, Hygrophila spinosa, Picrorhiza kurooa, Tinospora cordifolia and Zingiber officinale were selected to screen for the in vitro immunostimulant activity against the shrimp pathogen Vibrio harveyi using different organic polar and non-polar solvents. After initial screening, the best extract of the five herbs was mixed thoroughly in equal proportion and made it an artificial immunostimulant diets (ISD) such as ISD-1(500), ISD-2 (1,000), ISD-3 (1,500) and ISD-4 (2,000) mg?kg^?1. The control diet was prepared without adding immunostimulant herbal extracts. The Indian white shrimp, Fenneropenaeus indicus having the weight of 8.0?±?1.0?g, were fed with the above diets for 60?days. After the completion of feeding trail, they were challenged with V. harveyi at the rate of 10⁷CFU/ml and found out the cumulative mortality, growth parameters, haematological and immunological parameters. The weight gain and specific growth rate were significantly (P?<?0.05) increased from the control group to experimental group. The immunostimulant active principles helped to decrease the coagulation time and improved the total haemocyte count (THC), phagocytosis, phenol oxidase (PO) activity, haemagglutinin activity and bacterial clearance.     

Cell-mediated immune responses to a killed Salmonella enteritidis vaccine: lymphocyte proliferation, T-cell changes and interleukin-6 (IL-6), IL-1, IL-2, and IFN-gamma production

Two experimental approaches were used to investigate the immunological responses of chickens to a commercial killed Salmonella enteritidis (SE) vaccine. In the first, the effects of host age on antigen-specific proliferative responses and cytokine production were examined. Compared with non-vaccinated controls, 4-wk-old vaccinated chickens showed higher proliferation to SE LPS and flagella. The lymphoproliferation responses to these antigens of 8-mo-old vaccinated chickens were not different compared to the non-vaccinated controls. Increased production of interferon-gamma (IFN-gamma) and interleukin-2 (IL-2) by antigen-stimulated splenocytes following vaccination were, in general, more often observed in 4-wk-old compared with 8-mo-old chickens, whereas serum levels of these cytokines were consistently higher in the vaccinated birds compared with controls regardless of age. The second set of experiments were designed to determine the effects of SE vaccination on mitogen- or antigen-induced splenocyte proliferation and serum nitric oxide (NO) and cytokine levels. Splenocytes from vaccinated chickens stimulated with SE flagella showed significantly increased numbers of TCRgammadelta+ cells at 7 days post-vaccination compared with non-vaccinated birds. In contrast, no differences were noted with CD4+, CD8+, or TCRalphabeta+ cells at any time points examined. Higher levels of NO production were observed following stimulation with SE flagella at 4, 7, 11, and 14 days after SE vaccination while serum levels of IFN-gamma, IL-1, IL-6, and IL-8 were elevated only at day 7 post-vaccination. In conclusion, younger chickens mounted a more robust antigen-specific immune response to the SE vaccine compared with older birds and vaccination induced not only T-cell-mediated responses but also host innate and pro-inflammatory responses.     

Sequential changes in lactate,isocitrate, and malate dehydrogenases in mice exposed to technical grade hexachlorocyclohexane (BHC) and their possible relationship to liver tumors

Hexachlorocyclohexane (BHC) was fed at a 500-ppm-dose level in diet to pure inbred Swiss mice for 2, 4, 6, and 8 months. Later BHC was discontinued for 4 months and subsequently the animals were refed BHC for 1 month. The protein, lactate dehydrogenase (E.C.1.1.1.27), isocitrate dehydrogenase (E.C.1.1.1.42), and malate dehydrogenase (E.C.1.1.1.37) were studied from liver. The liver weight as percentage of body weight was also determined. The results showed an increase in the liver weight/body weight ratio and a decrease in protein and all three enzymes after BHC feeding for the different time intervals. The discontinuation of BHC in the diet resulted in the reversion of values of the above parameters toward the normal and after refeeding BHC for 1 month, the decreased values, as seen after initial BHC feeding, were again observed. This indicates that the changes in the values of lactate dehydrogenase, isocitrate dehydrogenase, and malate dehydrogenase are associated with hexachlorocyclohexane feeding in the diet. The significance of these changes is discussed.     

Host range of Alternaria alternata—a potential fungal biocontrol agents for waterhyacinth in India

The host ranges of Alternaria alternata and fungi native to India and pathogen of waterhyacinth (Eichhornia crassipes) were evaluated using 29 plant species (some with several cultivars tested) representing 18 families of economic and ecological importance. The results showed that only waterlettuce (Pistia stratiotes), another common weed in India, was infected by A. alternata. The use of these pathogens in the biological control of waterhyacinth would not be expected to affect plants of economic and ecological importance in India.     

Anti-abortion and Fertility Vaccine Potential of Defined Double Deletion (ΔaroAΔhtrA) Mutant (S30) of Salmonella Abortusequi in Equids

The present study on defined double deletion (ΔaroAΔhtrA) mutant (S30) of Salmonella enterica serovar Abortusequi evaluated it for safety, immunogenicity, and efficacy as a vaccine candidate in equids. The candidate strain was found safe in equids (foals, male and female horses and donkeys, and pregnant and nonpregnant mares) and induced good humoral and cell-mediated immunity on administration through oral route. The strain was not excreted in feces of vaccinated animals. The vaccine candidate administered orally (1 × 10¹¹ cfu per animal) protected mares even after 180 days of inoculation against abortion on challenge with wild-type S. Abortusequi strain whereas in nonvaccinated control, all mares aborted. The vaccination in infertile mares resulted in regaining of fertility in 67%–80% thoroughbred mares at two different breeding farms. Further, the humoral immunity was transferred to foals from vaccinated mothers through colostrum, but no placental transfer was evident. Thus, the vaccine under study may be recommended for use in equids to control S. Abortusequi infection–associated abortions and also to enhance fertility of temporarily infertile mares in endemic areas.     

Uniparental inheritance of purple leaf and the associated resistance to leafminer in castor bean

Leafminer ( Liriomyza trifolii Burgess), Diptera Agromyzidae, is one of the insect pests that causes economic damage to castor bean ( Ricinus communis L.) foliage. Green leaf type is a common phenotype in castor bean and highly susceptible to leafminer. The rare purple leaf type germplasm accessions showed stable resistance to leafminer. Studies were carried out to understand the inheritance of purple leaf and the associated leafminer resistance. Direct and reciprocal crosses were made between a purple leaf parent RG1930 and a green leaf parent RG2788. RG1930 is resistant to leafminer while RG2788 is susceptible. Reciprocal differences were noted in segregation pattern of purple leaf colour as well as resistance to leafminer. Purple leaf phenotype was obtained only in purple × green (RG1930 × RG2788) cross where the female parent was a purple leaf phenotype. The reciprocal cross green × purple (RG2788 × RG1930) produced only the green leaf phenotype. Uniparental inheritance was observed for purple leaf phenotype and resistance to leafminer in F₁, F₂, F₃ and backcross generations. Progenies with a dark purple leaf were resistant to leafminer while those with a green leaf were susceptible. Visual association between a purple leaf and resistance to leafminer and their uniparental inheritance were clearly established. The role of heritable epigenetic effects are discussed in expression of purple pigment in offspring.     

Tonicity effects on intact single muscle fibers: relation between force and cell volume

Contraction of isolated, intact frog muscle fibers under increasing tonicity of the external solution was studied by adding (i) effectively impermeant sodium chloride and sucrose and (ii) permeant potassium chloride. Force of isometric contraction decreased as a function of tonicity, independent of the permeability of the solute. In contrast, cell volume changed with tonicity in impermeant solutes and was constant with potassium chloride. The results are evidence that ionic strength in the sarcoplasm directly influences the contraction mechanism. Also, the findings show that force development is unaffected by changes in fiber volume, suggesting that the force per cross-bridge is constant at different distances between the thin and myofilaments. Finally, in light of the length-force relation, the results support the idea that cross-bridges are independent force generators.     

Molecular basis for the influence of muscle length on myocardial performance

According to Starling's law of the heart, the force of contraction during the ejection of blood is a function of the end-diastolic volume. To seek the molecular explanation of this effect, a study was made of the effects of length on Ca2+ sensitivity during tension development by isolated demembranated cardiac muscle in which the cardiac form of troponin C was substituted with skeletal troponin C. The results of troponin C exchange were compared at sarcomere lengths of 1.9 and 2.4 micrometers. Enhancement of the myocardial performance at the stretched length was greatly suppressed with the skeletal troponin C compared with the cardiac troponin C. Thus the troponin C subunit of the troponin complex that regulates the activation of actin filaments has intrinsic molecular properties that influence the length-induced autoregulation of myocardial performance and may be a basis for Starling's law of the heart.     

Controlled-environment and field evaluation of heat stress induced genetic variability on translocation efficiency and grain filling traits in rice

Journal of Crop Science and Biotechnology - The grain filling of rice is gets weakened by heat stress due to reduced spike photosynthesis at high temperature stress. An alternate source of carbon...