A yellows disease system with differing principal host plants for the obligatory pathogen and its vector

A stolbur‐type phytoplasma is the putative pathogen of grapevine yellows disease that causes economic damage to vineyards in most growing areas around the world. The pathogen is known to be transmitted to vines by two planthoppers, Hyalesthes obsoletus and Reptalus panzer; the latter is found in Europe but has not yet been observed in Israel. The establishment of a vector–pathogen–plant relationship requires that the pathogen and the vector meet on a shared host plant. This does not happen in the ecosystem examined here, where two different principal host plants for the obligate pathogen and its vector exist: the pathogen is established on vines, while its vector, H. obsoletus, develops on Vitex agnus‐castus. The present study verified that: (i) the vector cannot complete its life cycle on vines; (ii) V. agnus‐castus does not grow in the immediate vicinity of vines, and does not harbour the pathogen; and (iii) the pathogen is not vertically transmitted from mother to offspring. Moreover, in a thorough search of plants in vine growing areas, no other plants were found that host both the vector and the pathogen. However, it was found that the planthopper can acquire the phytoplasma from infected vines. Nonetheless, this does not prove the ability of the planthopper to further transmit the pathogen to vines and does not explain the presence of the vector on the non‐preferred vines. Thus, the enigma of the pathogen–vector–host triangle in this system remains unresolved.     

A diazotrophic, indole-3-acetic acid-producing endophyte from wild cottonwood

An endophytic bacterium, wild poplar strain B (WPB), isolated from stems of wild cottonwood (Populus trichocarpa) was identified to Burkholderia vietnamiensis by analyzing the recA and rDNA genes. Phylogenetic analysis of the nifHDK cluster indicates that the WPB isolate shares high sequence similarity with known B. vietnamiensis strains. The nitrogenase activity of WPB was determined by a ¹⁵N₂ incorporation assay and an acetylene reduction assay. WPB was also monitored for production of indole-3-acetic acid (IAA), a phytohormone which can promote plant growth, when incubated with l-tryptophan. In addition, its plant growth promotion capacity was assessed by inoculating the WPB strain onto Kentucky bluegrass in nitrogen-free medium. Compared to uninoculated control plants, the plants inoculated with WPB gained more dry weight (42%, p = 0.01) and more nitrogen content (37%, p = 0.04) in 50 days.     

Conventional and future diagnostics for avian influenza

The significant and continued transboundary spread of Asian avian influenza H5N1 since 2003, paired with documented transmission from avian species to humans and other mammals, has focused global attention on avian influenza virus detection and diagnostic strategies. While the historic and conventional laboratory methods used for isolation and identification of the virus and for detection of specific antibodies continued to be widely applied, new and emerging technologies are rapidly being adapted to support avian influenza virus surveillance and diagnosis worldwide. Molecular tools in particular are advancing toward lab-on-chip and fully integrated technologies that are capable of same day detection, pathotyping, and phylogenetic characterization of influenza A viruses obtained from clinical specimens. The future of avian influenza diagnostics, rather than moving toward a single approach, is wisely adopting a strategy that takes advantage of the range of conventional and advancing technologies to be used in "fit-for-purpose" testing.     

Di-tri-octahedral smectite for the prevention of post-operative diarrhea in equids with surgical disease of the large intestine: Results of a randomized clinical trial

The aim of this study was to evaluate the effects of a commercially available di-tri-octahedral (DTO) smectite product on clinical signs and prevalence of post-operative diarrhea in horses with colic associated with disease of the large intestine. Sixty-seven horses with surgical disease of the large intestine were randomly assigned to be treated with DTO smectite (n = 37; 0.5 kg via nasogastric intubation every 24 h for 3 days post-operatively) or a placebo (n = 30). The effect of treatment on fecal scores and clinical and hematological parameters, including heart rate, mucous membrane color, temperature, total white blood cell count, total neutrophil count and total plasma protein values, were determined.Horses treated with DTO smectite had a significant reduction in the prevalence of post-operative diarrhea (10.8%), compared with controls (41.4%). A significant improvement in mucous membrane color was observed 72 h post-operatively in horses receiving treatment, compared with placebo. Administration of DTO smectite to colic patients with disease of the large intestine reduced the occurrence of diarrhea in the early post-operative period.     

Structural characterization of alpha-zein

A variety of published physical measurements, computational algorithms, and structural modeling methods have been used to create a molecular model of 19 kDa alpha-zein (Z19). Zetaeins are water-insoluble storage proteins found in corn protein bodies. Analyses of the protein sequence using probability algorithms, structural studies by circular dichroism, infrared spectroscopy, small-angle X-ray scattering (SAXS), light scattering, proton exchange, NMR, and optical rotatory dispersion experiments suggest that Z19 has approximately 35-60% helical character, made up of nine helical segments of about 20 amino acids with glutamine-rich "turns" or "loops". SAXS and light-scattering experiments suggest that in alcohol/water mixtures alpha-zein exists as an oblong structure with an axial ratio of approximately 6:1. Furthermore, ultracentifugation, birefringence, dielectric, and viscosity studies indicate that alpha-zein behaves as an asymmetric particle with an axial ratio of from 7:1 to 28:1. Published models of alpha-zein to date have not been consistent with the experimental data, and for this reason the structure was re-examined using molecular mechanics and dynamics simulations creating a new three-dimensional (3D) structure for Z19. From the amino acid sequence and probability algorithms this analysis suggested that alpha-zein has coiled-coil tendencies resulting in alpha-helices with about four residues per turn in the central helical sections with the nonpolar residue side chains forming a hydrophobic face inside a triple superhelix. The nine helical segments of the 19 kDa protein were modeled into three sets of three interacting coiled-coil helices with segments positioned end to end. The resulting structure lengthens with the addition of the N- and C-terminal sections, to give an axial ratio of approximately 6 or 7:1 in agreement with recent experiments. The natural carotenoid, lutein, is found to fit into the core of the triple-helical segments and help stabilize the configuration. Molecular dynamics simulations with explicit methanol/water molecules as solvent have been carried out to refine the 3D structure.     

Incorporation of alpha-tocopherol and linoleic acid in fresh lambs by feeding chemically treated dietary supplements containing dl-alpha-tocopheryl acetate and sunflower oil

The effects of feeding chemically treated dietary supplements (CTDS) containing sunflower oil and dl-alpha-tocopheryl acetate (TA) on alpha-tocopherol content and fatty acid profile in edible tissues of lambs were estimated. Compared with lambs fed control diet (CD), lambs fed CD plus 250 IU of either TA or CTDS increased serum alpha-tocopherol. The CTDS-fed lambs further increased serum alpha-tocopherol by 29% over those fed CD plus 250 IU of TA. Lambs supplemented with TA or CTDS increased alpha-tocopherol in muscle and adipose tissues as compared with lambs fed CD. The CTDS-fed lambs had higher levels of alpha-tocopherol in gluteus medius (7.55 vs 6.05 mug/g), psoas major (7.43 vs 6.02 mug/g), and subcutaneous fat (12.6 vs 9.98 mug/g) compared with the TA-fed lambs. Feeding lambs CTDS also substantially increased levels of linoleic acid in the adipose tissues while decreasing the content of palmitic and oleic acids.     

Identification of QTLs associated with salinity tolerance at late growth stage in barley

Salinity is a major abiotic stress to barley (Hordum vulgare L.) growth and yield. In the current study, quantitative trait loci (QTL) for yield and physiological components at the late growth stage under salt stress and non-stress environments were determined in barley using a double haploid population derived from a cross between CM72 (salt-tolerant) and Gairdner (salt-sensitive). A total of 30 QTLs for 10 traits, including tiller numbers (TN), plant height, spikes per line (SPL), spikes per plant (SPP), dry weight per plant, grains per plant, grain yield, shoot Na⁺ (NA) and K⁺ concentraitions (K) in shoot, and Na⁺/K⁺ ratio (NAK), were detected, with 17 and 13 QTLs under non-stress and salt stress, respectively. The phenotypic variation explained by individual QTL ranged from 3.25 to 29.81%. QTL flanked by markers bPb-1278 and bPb-8437 on chromosomes 4H was associated with TN, SPL, and SPP under salt stress. This locus may be useful in the breeding program of marker-assisted selection for improving salt tolerance of barley. However, QTLs associated with NA, K, and NAK differed greatly between non-stress and salt stress environments. It may be suggested that only the QTLs detected under salt stress are really associated with salt tolerance in barley. D. Xue and Y. Huang contributed equally to the article.     

A perspective on management of Helicoverpa armigera: transgenic Bt cotton,IPM, and landscapes

Helicoverpa armigera is a major pest of agriculture, horticulture and floriculture throughout the Old World and recently invaded parts of the New World. We overview of the evolution in thinking about the application of area‐wide approaches to assist with its control by the Australian Cotton Industry to highlight important lessons and future challenges to achieving the same in the New World. An over‐reliance of broad‐spectrum insecticides led to Helicoverpa spp. in Australian cotton rapidly became resistant to DDT, synthetic pyrethroids, organophosphates, carbamates and endosulfan. Voluntary strategies were developed to slow the development of insecticide resistance, which included rotating chemistries and basing spray decisions on thresholds. Despite adoption of these practices, insecticide resistance continued to develop until the introduction of genetically modified cotton provided a platform for augmenting Integrated Pest Management in the Australian cotton industry. Compliance with mandatory resistance management plans for Bt cotton necessitated a shift from pest control at the level of individual fields or farms towards a coordinated area‐wide landscape approach. Our take‐home message for control of H. armigera is that resistance management is essential in genetically modified crops and must be season long and area‐wide to be effective. © 2016 Society of Chemical Industry