Stress mitigating and immunomodulatory effect of dietary pyridoxine in Labeo rohita (Hamilton) fingerlings

A 60‐day experiment was carried out to delineate stress mitigating and immunomodulatory role of dietary pyridoxine (PN) in Labeo rohita fingerlings exposed to endosulfan. Two hundred and seventy fingerlings were randomly distributed into six treatments in triplicates. Five iso‐caloric and iso‐nitrogenous purified diets were prepared with graded levels of pyridoxine. Six treatment groups were T₀ (10 mg PN+without endosulfan), T₁ (0 mg PN+endosulfan), T₂ (10 mg PN+endosulfan), T₃ (50 mg PN+endosulfan), T₄ (100 mg PN+endosulfan) and T₅ (200 mg PN+endosulfan). The role of pyridoxine on stress mitigation and immunomodulation was assessed by biochemical and haemato‐immunological parameters like aspartate aminotransaminase, alanine aminotransaminase, lactate dehydrogenase, malate dehydrogenase, superoxide dismutase and catalase were significantly (P<0.05) lower while acetylcholinesterase was significantly (P<0.05) higher in pyridoxine‐fed groups. Erythrocytes count, haemoglobin content and total serum protein, albumin, globulin, nitroblue tetrazolium and lysozyme activity were significantly (P<0.05) higher while cortisol and blood glucose were decreased significantly (P<0.05) in pyridoxine‐fed groups. Percentage survival after challenge with Aeromonas hydrophila was highest in T₀ group. The results obtained in present study indicate that dietary pyridoxine supplementation at 100 mg PN kg^?1 diet reduces the endosulfan‐induced stress and triggers immune response in L. rohita fingerlings.     

Seroepizootiological survey for selected viral infections in captive Asiatic lions (Panthera leo persica) from western India.

Infectious diseases have been responsible for large-scale declines in many endangered animals. Disease outbreaks in small populations have probably led to the eventual extinction of such endangered animals in the wild. The endangered Asiatic lion (Panthera leo persica) population may also face such threats. This was evident from this study on captive Asiatic lions from western India, which were sampled from December 1998 to March 1999. Fifty-six Asiatic lions, including 17 hybrid lions (Afro-Asian crosses) from six captive centers in western India, were tested for antibodies against canine distemper virus (CDV), feline parvovirus (FPV), feline immunodeficiency virus (FIV), and feline leukemia viral (FeLV) antigen. Agar gel immunodiffusion test and dot immunobinding assay were employed for CDV and FPV antibody detection. Commercial enzyme-linked immunosorbent assay kits were used for FIV antibody and FeLV antigen detection. Forty-nine of 56 lions (87.5%) were positive for CDV. All 56 (100%) lions were positive for FPV antibodies. There were no detectable levels of FIV antibodies and FeLV antigens. It was observed that CDV and FPV, two viruses known to cause high mortality in captive carnivores, were widely prevalent in these captive Asiatic lions. It is suggested that these seropositive animals will have the potential to pose a risk of infection to other seronegative animals. Hence, it is imperative to carefully consider any movement, translocation, or reintroduction of these animals to new regions. It is also recommended that these animals be required to undergo standard quarantine and disease screening protocols. The lack of exposure to pathogens, such as FIV and FeLV, would also be a risk, and, hence, identification of reservoirs and screening of in-contact animals is highly recommended. Vaccinations must be considered, using killed or other suitable viral vaccines, which have been proved to be safe, effective, and efficacious in endangered felids.     

Antixenosis and antibiosis mechanisms of resistance to pod borer, <Emphasis Type="Italic">Helicoverpa armigera</Emphasis> in wild relatives of chickpea, <Emphasis Type="Italic">Cicer arietinum</Emphasis>

The noctuid pod borer, Helicoverpa armigera is one of the most damaging pests of chickpea, Cicer arietinum. The levels of resistance to H. armigera in the cultivated chickpea are low to moderate, but the wild relatives of chickpea have exhibited high levels of resistance to this pest. To develop insect-resistant cultivars with durable resistance, it is important to understand the contribution of different components of resistance, and therefore, we studied antixenosis and antibiosis mechanisms of resistance to H. armigera in a diverse array of wild relatives of chickpea. The genotypes IG 70012, PI 599046, IG 70022, PI 599066, IG 70006, IG 70018 (C. bijugum), ICC 506EB, ICCL 86111 (cultivated chickpea), IG 72933, IG 72953 (C. reticulatum), IG 69979 (C. cuneatum) and IG 599076 (C. chrossanicum) exhibited non preference for oviposition by the females of H. armigera under multi-choice, dual-choice and no-choice cage conditions. Based on detached leaf assay, the genotypes IG 70012, IG 70022, IG 70018, IG 70006, PI 599046, PI 599066 (C. bijugum), IG 69979 (C. cuneatum), PI 568217, PI 599077 (C. judaicum) and ICCW 17148 (C. microphyllum) suffered significantly lower leaf damage, and lower larval weights indicating high levels of antibiosis than on the cultivated chickpea. Glandular and non-glandular trichomes showed negative correlation with oviposition, while the glandular trichomes showed a significant and negative correlation with leaf damage rating. Density of non-glandular trichomes was negatively correlated with larval survival. High performance liquid chromatography (HPLC) fingerprints of leaf surface exudates showed a negative correlation of oxalic acid with oviposition, but positive correlation with malic acid. Both oxalic acid and malic acid showed a significant negative correlation with larval survival. The wild relatives exhibiting low preference for oviposition and high levels of antibiosis can be used as sources of resistance to increase the levels and diversify the basis of resistance to H. armigera in cultivated chickpea.     

Influence of growth hormones on adventitious root formation in semi-hardwood cuttings of <Emphasis Type="Italic">Celasturs paniculatus</Emphasis> Willd.: a contribution for rapid multiplication and conservation management

Celastrus paniculatus Willd. (Celastraceae) is an important medicinal tree valued for its seeds. Indiscriminate collection of this plant from the habitat zones has posed a serious threat to its existence in the wild, results in globally a threatened plant species. Ex situ conservation is a prioritized agenda of research for redlisted plant species. Semi-hardwood stem cuttings collected from 10 to 15 year old trees were treated with different concentrations (0, 0.5, 1.0, 2.0, 3.0, 4.0 and 5.0 g l⁻¹) of growth hormones; indole-3-acetic acid (IAA), indole-3-butyric acid (IBA) and 1-naphthalene acetic acid (NAA) for positive effect on root induction. After 90 days of treatment, results were analyzed for percentage of rooting, root number and average root length per rooted cuttings. The highest rooting (57%) response with highest number of roots (~77.2) was obtained in indole-3-acetic acid at 3.0 g l⁻¹. Overall, high significant (P ≤ 0.05) rooting response was noticed in IAA treatment comparative to hormones IBA and NAA. Rooted cuttings exhibited 100% survival in the experimental field. This study reveals the propagation of semi-hardwood cuttings derived from partially matured branches is possible and it provides a basis for conservation of this threatened plant species by reducing pressure on its natural populations.     

Differential heat sensitivity of two cool-season legumes,chickpea and lentil,at the reproductive stage,is associated with responses in pollen function,photosynthetic ability and oxidative damage

Increasing temperatures are adversely affecting various food crops, including legumes, and this issue requires attention. The growth of two cool-season food legumes, chickpea and lentil, is inhibited by high temperatures but their relative sensitivity to heat stress and the underlying reasons have not been investigated. Moreover, the high-temperature thresholds for these two legumes have not been well-characterised. In the present study, three chickpea (ICCVO7110, ICC5912 and ICCV92944) and two lentil (LL699 and LL931) genotypes, having nearly similar phenology with respect to flowering, were grown at 30/20°C (day/night; control) until the onset of flowering and subsequently exposed to varying high temperatures (35/25, 38/28, 40/30 and 42/32°C; day/night) in a controlled environment (growth chamber; 12 hr/12 hr; light intensity 750 µmol m⁻² s⁻¹; RH-70%) at 108 days after sowing for both the species. Phenology (podding, maturity) was accelerated in both the species; the days to podding declined more in lentil at 35/25 (2.8 days) and 38/28°C (11.3 days) than in chickpea (1.7 and 7.1 days, respectively). Heat stress decreased flowering–podding and podding–maturity intervals considerably in both the species. At higher temperatures, no podding was observed in lentil, while chickpea showed reduction of 14.9 and 16.1 days at 40/30 and 42/32°C, respectively. Maturity was accelerated on 15.3 and 12.5 days at 38/28°C, 33.6 and 34 days at 40/30°C and 45.6 and 47 days at 42/32°C, in chickpea and lentil, respectively. Consequently, biomass decreased considerably at 38/28°C in both the species to limit the yield-related traits. Lentil was significantly more sensitive to heat stress, with the damage—assessed as reduction in biomass, reproductive function-related traits (pollen viability, germination, pollen tube growth and stigma receptivity), leaf traits such as membrane injury, leaf water status, photochemical efficiency, chlorophyll concentration, carbon fixation and assimilation, and oxidative stress, appearing even at 35/25°C, compared with 38/28°C, in chickpea. The expression of enzymatic antioxidants such as superoxide dismutase, catalase, ascorbate peroxidase, glutathione reductase and non-enzymatic antioxidants declined remarkably with heat stress, more so in lentil than in chickpea. Carbon fixation (assessed as Rubisco activity) and assimilation (assessed as sucrose concentration, sucrose synthase activity) were also reduced more in lentil than in chickpea, at all the stressful temperatures, resulting in more inhibition of plant biomass (shoot + roots), damage to reproductive function and severe reduction in pods and seeds. At 38/28°C, lentil showed 43% reduction in biomass, while it declined by 17.2% in chickpea at the same time, over the control temperature (30/20°C). At this temperature, lentil showed 53% and 46% reduction in pods and seed yield, compared to 13.4% and 22% decrease in chickpea at the same temperature. At 40/30°C, lentil did not produce any pods, while chickpea was able to produce few pods at this temperature. This study identified that lentil is considerably more sensitive to heat stress than chickpea, as a result of more damage to leaves (photosynthetic ability; oxidative injury) and reproductive components (pollen function, etc.) at 35/25°C and above, at controlled conditions.     

Tapping the potential of Solanum lycopersicum L. pertaining to salinity tolerance: perspectives and challenges

Genetic Resources and Crop Evolution - Crop breeding for abiotic stress tolerance entails introgression of stress tolerant genes into the cultivated types. With the augmentation in salt tolerance,...     

Comparative study of the structure of chromosome 1R derived from Secale montanum and Secale cereale

We produced 15 dissection lines of common wheat carrying segments of chromosome 1R of wild rye (Secale montanum) (1R^m) by the gametocidal system. Using the 1R^m dissection lines and previously established 24 dissection lines of chromosome 1R from cultivated rye (Secale cereale cv. ‘Imperial’) (1Rⁱ), we conducted cytological mapping of 97 markers that were amplified in the 1Rⁱ addition line. Sixty‐eight of the 97 markers were amplified in the 1R^m addition line. To reveal what structural differentiation occurred in chromosome 1R during domestication, we compared the cytological map of chromosome 1Rⁱ with that of chromosome 1R^m, and also with the previously published cytological map of chromosome 1R from wheat cultivar ‘Burgas 2’ (1R^B). There was one discrepancy in marker order in the satellite region between chromosomes 1Rⁱ and 1R^B, while there were four discrepancies in marker order between chromosomes 1Rⁱ and 1R^m. These results suggested that during the domestication of rye, some intrachromosomal rearrangements had occurred in chromosome 1R, although this chromosome is regarded as the most stable chromosome in the rye genome.     

Molecular markers for yellow stem borer Scirpophaga incertulas (Walker) resistance in rice

Breeding for yellow stem borer resistance in rice is difficult owing to the complex genetics of the trait and inherent difficulties in screening. Identification of molecular markers linked to the trait would enhance phenotypic evaluation for the trait. An F₂ population was developed using parents contrasting in their reaction to yellow stem borer resistance. Random Amplified Polymorphic DNA (RAPD) analysis,in conjunction with bulked segregant analysis, enabled us to identify four phenotype-specific RAPD markers. The markers C1₃₂₀ and K6₆₉₅ were linked with resistance and AH5₆₆₀ and C4₁₃₀₀ with susceptibility. The markers K6₆₉₅ and AH5₆₆₀ were linked to the gene(s) at distances of 12.8 cM and 14.9 cM, respectively. Scoring of these markers in a set of germplasm confirmed their reproducibility and their association with the trait. This revised version was published online in August 2006 with corrections to the Cover Date.