Identification of quantitative trait loci controlling soybean seed weight in recombinant inbred lines derived from PI 483463 (Glycine soja) × ‘Hutcheson’ (G. max)

The objective of this study was to identify quantitative trait loci (QTLs) controlling 100‐seed weight in soybean using 188 recombinant inbred lines (RIL) derived from a cross of PI 483463 and ‘Hutcheson’. The parents and RILs were grown for 4 years (2010–2013), and mature, dry seeds were used for 100‐seed weight measurement. The variance components of genotype (a), environment (e) and a × e interactions for seed weight were highly significant. The QTL analysis identified 14 QTLs explaining 3.83–12.23% of the total phenotypic variation. One of the QTLs, qSW17‐2, was found to be the stable QTL, being identified in all the environments with high phenotypic variation as compared to the other QTLs. Of the 14 QTLs, 10 QTLs showed colocalization with the seed weight QTLs identified in earlier reports, and four QTLs, qSW5‐1, qSW14‐1, qSW15‐1 and qSW15‐2, found to be the novel QTLs. A two‐dimensional genome scan revealed 11 pairs of epistatic QTLs across 11 chromosomes. The QTLs identified in this study may be useful in genetic improvement of soybean seed weight.     

Changing trends in mastitis

The global dairy industry, the predominant pathogens causing mastitis, our understanding of mastitis pathogens and the host response to intramammary infection are changing rapidly. This paper aims to discuss changes in each of these aspects. Globalisation, energy demands, human population growth and climate change all affect the dairy industry. In many western countries, control programs for contagious mastitis have been in place for decades, resulting in a decrease in occurrence of Streptococcus agalactiae and Staphylococcus aureus mastitis and an increase in the relative impact of Streptococcus uberis and Escherichia coli mastitis. In some countries, Klebsiella spp. or Streptococcus dysgalactiae are appearing as important causes of mastitis. Differences between countries in legislation, veterinary and laboratory services and farmers' management practices affect the distribution and impact of mastitis pathogens. For pathogens that have traditionally been categorised as contagious, strain adaptation to human and bovine hosts has been recognised. For pathogens that are often categorised as environmental, strains causing transient and chronic infections are distinguished. The genetic basis underlying host adaptation and mechanisms of infection is being unravelled. Genomic information on pathogens and their hosts and improved knowledge of the host's innate and acquired immune responses to intramammary infections provide opportunities to expand our understanding of bovine mastitis. These developments will undoubtedly contribute to novel approaches to mastitis diagnostics and control.     

Testing a model to track fish migrations in polar regions using pop‐up satellite archival tags

The use of pop‐up archival satellite tags (PSATs) to geolocate marine fishes in polar regions is challenging due to the brevity of periods during which there is a defined sunrise and sunset. Models using other environmental parameters are thus required to supplement geolocation data in the estimation of marine migratory routes. The objective of this work was to create a simple method that would estimate the migratory pathways of Atlantic salmon (Salmo salar) in polar regions using temperature and depth recordings. Validated geolocations from PSATs were used to test and constrict the model. The model’s predicted migratory routes were within 100 km of the light‐based geolocations calculated by the tags. By constraining the trajectories through the geolocations, bias was reduced. Sensitivity analyses demonstrated that slight alterations of the location and timing of the start and end points did not affect the mean migratory route estimates. This method is a management tool that can determine the primary habitat areas for any surface‐ or bottom‐dwelling marine species – especially in polar regions, where other methods may be impossible.     

Effect of smoke-water and a smoke-isolated butenolide on the growth and genotoxicity of commercial onion

Smoke-water and a biologically active butenolide compound (3-methyl-2H-furo[2,3-c]pyran-2-one) derived from burning plant material, show stimulating effects on a number of agricultural and horticultural crops. In these trials, onion (Allium cepa L.) plants were treated (drenched) with either a 1:500 (v/v) smoke-water solution or a butenolide solution of 10⁻¹⁰ M under greenhouse conditions. Onion plants supplied with smoke-water and butenolide solution exhibited a significantly greater number of leaves, increased leaf length, and a higher fresh and dry leaf weight than untreated plants at 175 days after seed sowing (DASS) (third harvest). In addition, smoke-water and butenolide-treated onion plants exhibited a significantly higher bulb diameter and bulb weight than untreated plants, when these plants were harvested at 175 DASS. Overall, smoke-water was more effective than butenolide and achieved the highest harvest index. Genotoxicity was not detected in the bulbs of onion when they were treated with either smoke-water or butenolide.     

Leaf anatomical characteristics and physiological responses to short-term drought in Ziziphusmauritiana (Lamk.)

The aim of this work was to study the association between leaf anatomical characteristics and response to short-term drought stress in Ziziphusmauritiana Lamk. Six Z. mauritiana cultivars (Seb, Gola, Umran, Keitly, Q-29 and B-5/4) under field conditions in Israel's Negev desert were studied. Width of palisade mesophyll, spongy mesophyll and epidermis, xylem number and diameter in mid-vein were investigated with light microscopy. Short-term (3 weeks) drought stress tolerance was evaluated by monitoring plant response (leaf transpiration, diffusive resistance, chlorophyll fluorescence, leaf water potential and leaf relative water content). Greater epidermis and mesophyll widths and xylem diameters and densities were associated with increased tolerance to short-term water deficit expressed by preliminary wilting symptoms and proportional differences between initial and final physiological parameters. Significantly larger differences were found in Keitly, Umran and B-5/4 than in Seb, Gola and Q-29, indicating that the former cultivars are more sensitive to drought stress. Our results indicate that tolerance in descending order was Seb, Q-29, Gola, B-5/4, Keitly and finally Umran. The existence of an association between anatomical characteristics and short-term drought stress tolerance based on physiological responses is suggested.     

Further studies on graft-induced off-season flowering and fruiting in mango (Mangifera indica L.)

Summary

Defoliated shoots of cvs Alphonso, Dashehari, Totapari etc. (receptors), could be induced to flower within four weeks during the off-season by veneer grafting them to leafy shoots of the off-season flowering cv. Royal Special (donor) during the non-flowering season. Experiments on defoliating the donor and receptor shoots revealed the crucial dual role of the leaves in flowering. In the ‘floral cycle’, leaves from the donor promoted flowering, whereas leaves on the receptors, in the vegative phase, were inhibitory, and prevented graft-induction of the receptors. Thus, for graft induction, leafy donors and defoliation of receptors were essential. The inhibitory effect of the leaves on the receptors was localized and did not affect flowering of the donor shoots’ The similarity between these findings and those in the herbaceous, day-length sensitive species strengthens the view that flower formation is controlled in the same way in herbaceous and in woody perennial species. A minimum threshold of the floral stimulus appeared to be another requirement for an optimum flowering response. This was concluded from an experiment in which the leafy receptors were defoliated on different dates during the off-season flowering cycle. At the end of cycle, the defoliated receptors produced small panicles, and finally only vegetative shoots, probably indicating sub-threshold levels of the stimulus. Bud activity at the apex in the receptor was also an important pre-requisite for graft-induction. Some veneer-grafted scions which remained dormant during the flowering cycle of the donor and which sprouted much later after the completion of off-season flowering, ‘escaped’ the stimulus and invariably turned out to be vegetative. It is postulated that the cyclic synthesis of the floral stimulus in the leaves in an inductive cycle, and the gap between two such cycles, mainly decides the flowering behaviour of mango cultivars—biennial, annual and multiflowering. Two other requiremets are the absence of non-induced leaves and the synchronization of meristematic activity in the bud with the inductive cycle. Juvenile shoots from one to four year old seedlings could not be graft-induced—unlike the shoots from mature, six year old seeding trees. This juvenility effect continued into the second year when defoliation of the receptor shoots had no effect and failed to induce them to flower.     

Development of a monoclonal antibody‐based flow‐through immunoassay (FTA) for detection of white spot syndrome virus (WSSV) in black tiger shrimp Penaeus monodon

A flow‐through immunoassay (FTA), an improved version of immunodot, was developed using a nitrocellulose membrane baked onto adsorbent pads enclosed in a plastic cassette to detect white spot syndrome virus (WSSV) in shrimp. Sharp purple dots developed with WSSV against the white background of the nitrocellulose membrane. The detection limits of WSSV by the FTA and immunodot were 0.312 and 1.2 μg mL^?1 crude WSSV protein, respectively. The FTA could be completed in 8–10 min compared with 90 min for immunodot. The FTA was 100 times more sensitive than 1‐step polymerase chain reaction (PCR) and in between that of the 1‐ and 2‐step PCR protocol recommended by the Office of International Epizootics (OIE). In experimental, orally infected shrimp post‐larvae, WSSV was first detected 14, 16 and 18 h post‐infection (hpi) by FTA, immunodot and one‐step PCR, respectively. The FTA detected WSSV 2 and 4 h earlier than immunodot and one‐step PCR, respectively. The FTA was more sensitive (25/27) than one‐step PCR (23/27) and immunodot (23/27) for the detection of WSSV from white spot disease outbreak ponds. The reagent components of the FTA were stable giving expected results for 6 m at 4–8 °C. The FTA is available as a rapid test kit called ‘RapiDot’ for the early detection of WSSV under field conditions.     

Pathogenicity of indole-3-acetic acid producing fungus <Emphasis Type="Italic">Fusarium delphinoides</Emphasis> strain GPK towards chickpea and pigeon pea

An indole-3-acetic acid (IAA) producing fungal strain was isolated from chickpea grown rhizospheric soil samples. Based on morphological and Internal Transcribed Spacer (ITS) region sequence analysis the new isolate was identified as Fusarium delphinoides. The Fusarium delphinoides strain produces and secretes IAA in-vitro as identified by HPLC and Mass spectrometry. The IAA production is dependent on tryptophan (Trp) as a nitrogen source in the medium. The IAA production is influenced by growth conditions such as pH of the medium, concentration of Trp and the nature of the carbon source. Additional nitrogen sources repress Trp dependent IAA production. Glucose and Trp served as the best carbon and nitrogen sources respectively. Pathogenicity of Fusarium delphinoides towards the plants was tested by electrolyte, nutrient leakage analysis and also by scoring the disease symptoms. Two cultivars of chickpea (ICCV-10 and L-550) and two cultivars of pigeon pea (Maruti and PT-221) were assessed for the pathogenicity by inoculating with spores of Fusarium delphinoides. The inoculation induced symptoms of Fusarium wilt as in the case of Fusarium oxysporum f. sp. ciceris (FOC), a known pathogen causing Fusarium wilt in chickpea. Electrolyte and nutrient leakage from the infected plants were used to assess the resistance, tolerance (moderately resistance) and susceptibility of the plants to the infection. Based on the results, both the pigeon pea cultivars (Maruti and PT-221) were rated as resistant, and ICCV-10 was rated as a tolerant cultivar of chickpea. However, chickpea cultivar L −550 was found to be a susceptible host for infection by Fusarium delphinoides. These results suggest that Fusarium delphinoides, which belongs to the Fusarium dimerum species group, is an IAA producing plant pathogen and causes wilt in chickpea. Further, along with pathogenicity tests, electrolyte and nutrient leakage analysis can be used to assess the pathogenicity of pathogenic fungi.     

Effect of adenovirus infection on adiposity in chicken.

Excessive fat accumulation has been observed in the field in chickens infected with adenovirus. In the present study this has been verified under experimental conditions. Chickens inoculated with adenovirus showed lesser weight gain but excessive adiposity compared to normal control chickens. These changes could not be explained by variation in food consumption. Chickens acquiring adenovirus naturally from the inoculated group showed similar adiposity. Serum cholesterol and triglyceride levels of inoculated and naturally infected chickens were significantly lower compared to those of the control group. Such an association between adenovirus infection and adiposity has been shown, probably, for the first time, which might help in further understanding of the complex problem of obesity.