Genetic analysis of resistance to watermelon bud necrosis orthotospovirus in watermelon [Citrullus lanatus (Thunb.) Matsum & Nakai]

An experiment was conducted to study the genetics and nature of gene action of resistance to watermelon bud necrosis orthotospovirus (WBNV) in watermelon. The experimental materials comprised of two resistant (BIL‐53 and IIHR‐19) and one susceptible (IIHR‐140) parents. Each of the resistant parents was crossed with the susceptible parent to develop six generations (P1, P2, F₁, F₂, BC1 and BC2) to study genetics. The results of segregation in F₂ and backcross progenies suggested that resistance is governed by a major dominant gene along with other background minor genes in both the crosses. BIL‐53 was found to possess higher degree of resistance with simple inheritance and hence may be of interest to breeders. Simple selection can be effective for improving the trait in the cross BIL‐53 × IIHR‐140 as additive gene action is prevalent.     

Varroa mites,viruses and bacteria incidences in Kenyan domesticated honeybee colonies

Varroa mite (Varroa destructor Anderson and Trueman) is a major global threat to the western honey bee (Apis mellifera L.). The ectoparasite has been implicated in the spread of honeybee viruses. Beekeeping plays a major role in transmission of the mite. The study aimed at assessing levels of Varroa infestation, bee viruses and bacteria incidences in domesticated honeybee colonies. Samples of adult honey bees, bee brood and Varroa mites were collected from Baringo, Narok, Kwale, Magarini, Voi, Ijara, Busia and Siaya in Kenya. Ten hives in each site were inspected for the presence of Varroa mites on adult bees using the icing sugar technique and forceps in sealed brood cells. The number of mites observed were recorded per site. Ribonucleic acid was extracted from the mites, brood and adult bees and a polymerase chain reaction was performed to detect the black queen cell virus. Pooled RNA samples of brood and adult bees were used in next generation sequencing on a 454 GS FLX platform to detect bee viruses and bacteria. Varroa mites were reported in all the study sites at varying levels. The black queen cell virus and three iflaviruses, European foul brood and its secondary causative agent Enterococcus faecalis were reported. The Kenyan honeybee population is threatened by bee pests and pathogens. There is a need for constant monitoring of bee pests and diseases in honeybee colonies in the country for early detection and to provide data on the status of bee health. All stakeholders in the beekeeping value chain should be enlightened on their role in pest and disease transmission.     

Extraction and electrophoretic analysis of large dsRNAs from desiccated plant tissues infected with plant viruses and biotrophic fungi

Extraction and electrophoretic analysis of large dsRNAs from plant and fungal tissues has been used successfully to detect RNA viruses infecting plants, fungi, and oomycetes. We modified a previously reported dsRNA extraction protocol and used it to detect a wide variety of plant and putative fungal viruses from infected plant tissues. The modified protocol was used successfully to extract large dsRNAs from 50 to 70 mg of desiccated plant tissues infected with acute and persistent RNA viruses and from plant tissues infected with biotrophic fungi causing rusts and powdery mildew diseases. The protocol proved to be efficient, fast, economic and versatile and requires relatively small amounts of desiccated tissue.     

Phytoremediation Potential of <Emphasis Type="Italic">Helianthus annuus</Emphasis> and <Emphasis Type="Italic">Hydrangea paniculata</Emphasis> in Copper and Lead-Contaminated Soil

This study was conducted to assess the hyperaccumulation and phytoremediation potential of copper (Cu) and lead (Pb) in Hardy ‘Limelight’ Hydrangea (Hydrangea paniculata) and the common sunflower (Helianthus annuus). The study also investigated the capacity of these two plants to transpire the metals in a temperature-controlled greenhouse. Plants were grown for 4 weeks and periodically watered with known elemental concentrations of copper oxide nanoparticles, copper sulfate, and lead nitrate. Both H. annuus and H. paniculata accumulated significant amounts of Cu and Pb to be classified as hyperaccumulator species. H. annuus took up significant amounts of Cu in the shoots, specifically the leaves (Cu max.?=?1368 ppm), and easily translocated it from stem to leaf (translocation factor (TF) ranged from 2.7 to 81.0). Pb was not as easily taken up and translocated (TF?=?0.6) as Cu was by this species. H. paniculata took up Cu and Pb in high concentrations but preferentially stored more metals in the stems (Cu max.?=?1757 ppm; Pb max.?=?780 ppm) than in the leaves (Cu max.?=?126 ppm; Pb max.?=?35 ppm). The translocation ability of H. paniculata was much lower for both metals compared to H. annuus. Both Cu and Pb transpired from H. annuus at concentrations of 0.04 and 0.005 ppm, respectively.     

Combination of Piper guineense Essential Oil with Cowpea Varietal Resistance in Control of Cowpea Seed Beetle,Callosobruchus maculatus Fabricius (Coleoptera: Chrysomelidae: Bruchinae)

To reduce the risks associated with over-dependence on synthetic insecticides and ensure leguminous food security,an experiment was conducted to evaluate the potentials of integrating Piper guineense essential oil(Pg EO)with cowpea varietal resistance in the control of cowpea seed beetle,Callosobruchus maculatus Fabricius.Four cowpea varieties(Sokoto,Drum,Oloyin and Gwallam)were studied.Data collected included oviposition,progeny emergence,Reproductive Efficiency(RE)and Percentage Seed Damage(PSD).At first filial generation,numbers of eggs laid on Oloyin variety treated with 25μL Pg EO per 25 g cowpea seeds(2.15)were significantly(p0.05)lower than the values obtained in untreated cowpea(3.61)and hexane-treated seeds(3.07).C.maculatus RE on Oloyin(33.73)was significantly(p0.05)lower than values obtained on other varieties(47.34-54.67)for seeds without Pg EO;and were significantly greater than 0.00 observed on Oloyin seeds treated with 50μL PgE O.PSD on Oloyin(6.63%)was significantly(p0.05)lower than the values obtained on Sokoto(10.04%)and Drum(9.79%)for seeds without Pg EO,while there was no damage in Oloyin treated with 50μL Pg EO.Significantly(p0.05)lower F2 progeny emergence occurred on Oloyin(4.02)and Sokoto(4.71)compared with Drum(9.03)and Gwallam(6.07)from the untreated cowpea seeds.The results implied that application of PgE O to Oloyin gave better protection from infestation of C.maculatus than other varieties.Hence,combination of varietal resistance with PgE O for management of bruchid could be an effective mean of improving cowpea food security.     

Total petroleum hydrocarbons and heavy metals in road-deposited sediments in Tijuana,Mexico

Purpose

A study was carried out to evaluate the concentration of heavy metals (Pb, Cu, Cr, Cd, and Hg) and total petroleum hydrocarbons (TPH) in road-deposited sediments (RDS) from Tijuana, Mexico, and identify their possible sources.

Materials and methods

Thirty RDS samples were randomly collected during the dry season using a brush and dustpan and classified according to construction material, traffic intensity, and land use. Soil samples were collected from a nonurban area and their concentrations were used as background values. For TPH, the samples were quantified gravimetrically after Soxhlet extraction, whereas heavy metals were extracted by acid digestion and their concentrations were measured by atomic absorption spectrometry.

Results and discussion

The mean TPH concentrations for RDS were 4208 mg kg^?1 and ranged from 1186 to 9982 mg kg^?1. For heavy metals, mean concentrations were 31.8, 50.2, 17.1, 0.1, and 0.1 mg kg^?1 for Pb, Cu, Cr, Cd, and Hg, respectively. The Igeo results showed that RDS from Tijuana are moderately to strongly polluted with Pb and Cu and moderately polluted with Cr. Principal component analysis (PCA) showed that Pb, Cu, and Cr could have their origin in tire wear, brake pads, bearings, and bushings.

Conclusions

The findings of this study revealed that RDS from Tijuana are polluted with TPH and heavy metals and that their principal sources are anthropogenic activities.

     

<Emphasis Type="Italic">Ungulate copiparvovirus 2</Emphasis> in healthy and postweaning multisystemic wasting syndrome-affected pigs

A SYBR Green-based real-time polymerase chain reaction (qPCR) was designed to detect Ungulate copiparvovirus 2, also known as porcine parvovirus 4 (PPV4). The test was applied to search for PPV4 DNAemia in sera from 1- to 4-month-old pigs displaying signs of postweaning multisystemic wasting syndrome (PMWS), as well as in sera from healthy swine at equivalent age and in sera from older healthy animals (>6 months old). High levels of PPV4 DNA were detected in PMWS-affected pigs. The mean viral DNA load in PMWS-affected pigs was 5.2 × 10⁷ copies/mL, whereas in young healthy pigs it was 1.4 × 10⁵ copies/mL (P ≤ 0.001). Although the copy numbers were lower in younger PMWS-affected individuals, this result sheds some light on the possible association between PPV4 viral load detection in this group and the immune impairment caused by PMWS.