A genome scan for quantitative trait loci affecting the Salmonella carrier-state in the chicken

Selection for increased resistance to Salmonella colonisation and excretion could reduce the risk of foodborne Salmonella infection. In order to identify potential loci affecting resistance, differences in resistance were identified between the N and 6₁ inbred lines and two QTL research performed. In an F2 cross, the animals were inoculated at one week of age with Salmonella enteritidis and cloacal swabs were carried out 4 and 5 wk post inoculation (thereafter called CSW4F2 and CSW4F2) and caecal contamination (CAECF2) was assessed 1 week later. The animals from the (N × 6₁) × N backcross were inoculated at six weeks of age with Salmonella typhimurium and cloacal swabs were studied from wk 1 to 4 (thereafter called CSW1BC to CSW4BC). A total of 33 F₂ and 46 backcross progeny were selectively genotyped for 103 and 135 microsatellite markers respectively. The analysis used least-squares-based and non-parametric interval mapping. Two genome-wise significant QTL were observed on Chromosome 1 for CSW2BC and on Chromosome 2 for CSW4F2, and four suggestive QTL for CSW5F2 on Chromosome 2, for CSW5F2 and CSW2BC on chromosome 5 and for CAECF2 on chromosome 16. These results suggest new regions of interest and the putative role of SAL1.     

Poultry Body Temperature Contributes to Invasion Control through Reduced Expression of Salmonella Pathogenicity Island 1 Genes in Salmonella enterica Serovars Typhimurium and Enteritidis

Salmonella enterica serovars Typhimurium (S. Typhimurium) and Enteritidis (S. Enteritidis) are foodborne pathogens, and outbreaks are often associated with poultry products. Chickens are typically asymptomatic when colonized by these serovars; however, the factors contributing to this observation are uncharacterized. Whereas symptomatic mammals have a body temperature between 37°C and 39°C, chickens have a body temperature of 41°C to 42°C. Here, in vivo experiments using chicks demonstrated that numbers of viable S. Typhimurium or S. Enteritidis bacteria within the liver and spleen organ sites were ≥4 orders of magnitude lower than those within the ceca. When similar doses of S. Typhimurium or S. Enteritidis were given to C3H/HeN mice, the ratio of the intestinal concentration to the liver/spleen concentration was 1:1. In the avian host, this suggested poor survival within these tissues or a reduced capacity to traverse the host epithelial layer and reach liver/spleen sites or both. Salmonella pathogenicity island 1 (SPI-1) promotes localization to liver/spleen tissues through invasion of the epithelial cell layer. Following in vitro growth at 42°C, SPI-1 genes sipC, invF, and hilA and the SPI-1 rtsA activator were downregulated compared to expression at 37°C. Overexpression of the hilA activators fur, fliZ, and hilD was capable of inducing hilA-lacZ at 37°C but not at 42°C despite the presence of similar levels of protein at the two temperatures. In contrast, overexpression of either hilC or rtsA was capable of inducing hilA and sipC at 42°C. These data indicate that physiological parameters of the poultry host, such as body temperature, have a role in modulating expression of virulence.     

Reproduction of Heterodera schachtii Schmidt on Resistant Mustard,Radish, and Sugar Beet Cultivars

The reproduction of a Wyoming population of Heterodera schachtii was determined for resistant trap crop radish (Raphanus sativus) and mustard (Sinapis alba) cultivars, and resistant and susceptible sugar beet (Beta vulgaris) cultivars in a greenhouse (21 °C/16 °C) and a growth chamber study (25 °C). Oil radish cultivars also were field tested in 2000 and 2001. In the greenhouse study, reproduction was suppressed similarly by the resistant sugar beet cultivar Nematop and all trap crop cultivars (P ≤ 0.05). In the growth chamber study, the radish cultivars were superior to most of the mustard cultivars in reducing nematode populations. All trap crops showed less reproduction than Nematop (P ≤ 0.05). In both studies, Nematop and all trap crops had lower Pf than susceptible sugar beet cultivars HH50 and HM9155 (P ≤ 0.05). In field studies, Rf values of radish cultivars decreased with increasing Pi of H. schachtii (r² = 0.59 in 2000 and r² = 0.26 in 2001). In 2000, trap crop radish cv. Colonel (Rf = 0.89) reduced nematode populations more than cv. Adagio (Rf = 4.67) and cv. Rimbo (Rf = 13.23) (P ≤ 0.05) when Pi was lower than 2.5 H. schachtii eggs and J2/cm³ soil. There were no differences in reproductive factors for radish cultivars in 2001 (P ≤ 0.05); Rf ranged from 0.23 for Adagio to 1.31 for Commodore for all Pi.     

Interaction of Fusarium oxysporum f. sp. ciceri and Meloidogyne javanica on Cicer arietinum

Interaction of Meloidogyne javanica and Fusarium oxysporum f. sp. ciceri was studied on Fusarium wilt-susceptible (JG 62 and K 850) and resistant (JG 74 and Avrodhi) chickpea cultivars. In greenhouse experiments, inoculation of M. javanica juveniles prior to F. oxysporum f. sp. ciceri caused greater wilt incidence in susceptible cultivars and induced vascular discoloration in roots of resistant cultivars. Nematode reproduction was greatest (P = 0.05) at 25 °C. Number of galls and percentage of root area galled increased when the temperature was increased from 15 °C to 25 °C. Wilt incidence was greater at 20 °C than at 25 °C. Chlorosis of leaves and vascular discoloration of plants did not occur at 15 °C. The nematode enhanced the wilt incidence in wilt-susceptible cultivars only at 25 °C. Interaction between the two pathogens on shoot and root weights was significant only at 20 °C, and F. o. ciceri suppressed the nematode density at this temperature. Wilt incidence was greater in clayey (48% clay) than in loamy sand (85% sand) soils. The nematode caused greater plant damage on loamy sand than on clayey soil. Fusarium wilt resistance in Avrodhi and JG 74 was stable in the presence of M. javanica across temperatures and soil types.     

Low levels of realized seed and pollen gene flow and strong spatial genetic structure in a small,isolated and fragmented population of the tropical tree Copaifera langsdorffii Desf

Over the past century, the Brazilian Atlantic forest has been reduced to small, isolated fragments of forest. Reproductive isolation theories predict a loss of genetic diversity and increases in inbreeding and spatial genetic structure (SGS) in such populations. We analysed eight microsatellite loci to investigate the pollen and seed dispersal patterns, genetic diversity, inbreeding and SGS of the tropical tree Copaifera langsdorffii in a small (4.8 ha), isolated population. All 112 adult trees and 128 seedlings found in the stand were sampled, mapped and genotyped. Seedlings had significantly lower levels of genetic diversity (A=16.5±0.45, mean±95% s.e.; H_e=0.838±0.006) than did adult trees (A=23.2±0.81; H_e=0.893±0.030). Parentage analysis did not indicate any seed immigration (m_seeds=0) and the pollen immigration rate was very low (m_pollen=0.047). The average distance of realized pollen dispersal within the stand was 94 m, with 81% of the pollen travelling <150 m. A significant negative correlation was found between the frequency and distance of pollen dispersal (r=−0.79, P<0.01), indicating that short-distance pollinations were more frequent. A significant SGS for both adults (∼50 m) and seedlings (∼20 m) was also found, indicating that most of the seeds were dispersed over short distances. The results suggested that the spatial isolation of populations by habitat fragmentation can restrict seed and pollen gene flow, increase SGS and affect the genetic diversity of future generations.     

Cumulative t-link threshold models for the genetic analysis of calving ease scores

In this study, a hierarchical threshold mixed model based on a cumulative t-link specification for the analysis of ordinal data or more, specifically, calving ease scores, was developed. The validation of this model and the Markov chain Monte Carlo (MCMC) algorithm was carried out on simulated data from normally and t₄ (i.e. a t-distribution with four degrees of freedom) distributed populations using the deviance information criterion (DIC) and a pseudo Bayes factor (PBF) measure to validate recently proposed model choice criteria. The simulation study indicated that although inference on the degrees of freedom parameter is possible, MCMC mixing was problematic. Nevertheless, the DIC and PBF were validated to be satisfactory measures of model fit to data. A sire and maternal grandsire cumulative t-link model was applied to a calving ease dataset from 8847 Italian Piemontese first parity dams. The cumulative t-link model was shown to lead to posterior means of direct and maternal heritabilities (0.40 ± 0.06, 0.11 ± 0.04) and a direct maternal genetic correlation (-0.58 ± 0.15) that were not different from the corresponding posterior means of the heritabilities (0.42 ± 0.07, 0.14 ± 0.04) and the genetic correlation (-0.55 ± 0.14) inferred under the conventional cumulative probit link threshold model. Furthermore, the correlation (> 0.99) between posterior means of sire progeny merit from the two models suggested no meaningful rerankings. Nevertheless, the cumulative t-link model was decisively chosen as the better fitting model for this calving ease data using DIC and PBF.     

Effects of Resistance in Phaseolus vulgaris on Development of Meloidogyne Species

Use of resistant Phaseolus vulgaris germplasm has a potential role in limiting damaging effects of Meloidogyne spp. on bean production. Effects of two genetic resistance systems in common bean germptasm on penetration and development of Meloidogyne spp. were studied under growth room conditions at 22°C to 25°C. Nemasnap (gene system 1) and G1805 (gene system 2) were inoculated with second-stage juveniles (J2) of M. incognita race 2 and M. arenaria race 1, respectively; Black Valentine was used as the susceptible control. Up to 7 days after inoculation, there were no differences in numbers of M. incognita J2 penetrating roots of Black Valentine and Nemasnap; subsequently, more nematodes were present in Black Valentine roots (P < 0.05). More nematodes reached advanced stages of development in Black Valentine than in Nemasnap roots (P < 0.05). Total numbers of M. arenaria were greater in Black Valentine than in G 1805 roots from 14 days after inoculation (P < 0.05). Advanced stages of development occurred earlier and in greater numbers in Black Valentine plants than in G1805 plants. In these studies, resistance to M. incognita race 2 and M. arenaria race 1 in bean germplasm, which contain gene system 1 and gene system 2, respectively, was expressed by delayed nematode development rather than by differential penetration compared with susceptible plants.     

A new species of plasmodiidae (Coccidia: Hemosporidia) from the blood of the skink Scincus hemprichii (Scincidae: Reptilia) in Saudi Arabia

Fallisia arabica n. sp. was described from peripheral blood smears of the Skink lizard, Scincus hemprichii from Jazan Province in the southwest of Saudi Arabia. Schizogony and gametogony take place within neutrophils in the peripheral blood of the host. Mature schizont is rosette shaped 17.5 ± 4.1 × 17.0 ± 3.9 μm, with a L/W ratio of 1.03(1.02–1.05) μm and produces 24(18–26) merozoites. Young gametocytes are ellipsoidal, 5.5 ± 0.8 × 3.6 ± 0.5 μm, with a L/W of 1.53(1.44–1.61) μm. Mature macrogametocytes are ellipsoidal, 9.7 ± 1.2 × 7.8 ± 1.0 μm, with a L/W of 1.24(1.21–1.34) μm and microgametocytes are ellipsoidal, 7.0 ± 1.1 × 6.8 ± 0.9 μm. with a L/W of 1.03(1.01–1.10) μm. In comparison to the described Fallisia species, this new taxon has rosette schizonts and is larger than F. dominicensis, in Hispaniola, F. bipocrati, F. poecilopi, in Panama, F. thecadactyli in Venezuela, and F. effusa, F. simplex, F. modesta, in Brazil. F. arabica has fewer merozoites than F. effusa, F. poecilopi, F. thecadactyli and F. siamense in Thailand. This new species has more merozoites than F. dominicensis and F. modesta. All of these species belong to diverse saurian families (Agamidae, Gekkonidae, Polychrotidae, Scincidae and Teiidae) parasitize only thrombocytes or lymphocytes and some species parasitize immature erythroid cells and leucocytes.     

Protection of human erythrocyte using Crinumasiaticum extract and lycorine from oxidative damage induced by 2-amidinopropane

The intention of this investigation was to evaluate the free radical scavenging activity and erythrocyte protective activity of ethanolic extract of Crinumasiaticum (L) and lycorine. The ethanolic extract of C. asiaticum (L) and lycorine were found to have different levels of antioxidant properties in the test models. Both ethanolic extract of C. asiaticum (L) (0.5–2.5 mg/ml) and lycorine (0.010 mg–0.050 mg/ml) increases the percentage of lipid peroxidation inhibition (26.25 ± 0.23% and 19.25 ± 0.23%) and enhances the free radical scavenging activity (20.92 ± 0.22% and 20.52 ± 0.22%), scavenging of hydrogen peroxide (25.67 ± 0.17% and 23.07 ± 0.3%) superoxide anion scavenging activity (27.69 ± 0.16% and 16.09 ± 0.7%) at concentration of 2.5 and 0.050 mg of C. asiaticum (L) and lycorine, respectively. But compared with tocopherol (P < 0.05) less activity was observed by C. asiaticum (L) and lycorine. The ethanolic extract of C. asiaticum (L) and lycorine were normalized to reduce the level of glutathione and also to sustain the status of protein in erythrocytes during the peroxyl radical [2,2-azobis (2-amidinopropane) dihydrochloride (AAPH)] induced oxidative damage in ex vivo model. The present results of the investigations demonstrated that protective nature of the C. asiaticum (L) and lycorine will be considered as a significant natural antioxidant source.     

DJ-1 protects against cell death following acute cardiac ischemia–reperfusion injury

Novel therapeutic targets are required to protect the heart against cell death from acute ischemia–reperfusion injury (IRI). Mutations in the DJ-1 (PARK7) gene in dopaminergic neurons induce mitochondrial dysfunction and a genetic form of Parkinson''s disease. Genetic ablation of DJ-1 renders the brain more susceptible to cell death following ischemia–reperfusion in a model of stroke. Although DJ-1 is present in the heart, its role there is currently unclear. We sought to investigate whether mitochondrial DJ-1 may protect the heart against cell death from acute IRI by preventing mitochondrial dysfunction. Overexpression of DJ-1 in HL-1 cardiac cells conferred the following beneficial effects: reduced cell death following simulated IRI (30.4±4.7% with DJ-1 versus 52.9±4.7% in control; n=5, P<0.05); delayed mitochondrial permeability transition pore (MPTP) opening (a critical mediator of cell death) (260±33 s with DJ-1 versus 121±12 s in control; n=6, P<0.05); and induction of mitochondrial elongation (81.3±2.5% with DJ-1 versus 62.0±2.8% in control; n=6 cells, P<0.05). These beneficial effects of DJ-1 were absent in cells expressing the non-functional DJ-1^L166P and DJ-1^Cys106A mutants. Adult mice devoid of DJ-1 (KO) were found to be more susceptible to cell death from in vivo IRI with larger myocardial infarct sizes (50.9±3.5% DJ-1 KO versus 41.1±2.5% in DJ-1 WT; n≥7, P<0.05) and resistant to cardioprotection by ischemic preconditioning. DJ-1 KO hearts showed increased mitochondrial fragmentation on electron microscopy, although there were no differences in calcium-induced MPTP opening, mitochondrial respiratory function or myocardial ATP levels. We demonstrate that loss of DJ-1 protects the heart from acute IRI cell death by preventing mitochondrial dysfunction. We propose that DJ-1 may represent a novel therapeutic target for cardioprotection.     

Temperature Effects on Heterorhabditis megidis and Steinernema carpocapsae Infectivity to Galleria mellonella

The effect of temperature on the infection of larvae of the greater wax moth, Galleria mellonella, by Heterorhabditis megidis H90 and Steinernema carpocapsae strain All, was determined. For both species, infection, reproduction, and development were fastest at 20 to 24 °C. Infection by both H. megidis and S. carpocapsae occurred between 8 and 16 °C; however, neither species reproduced at 8 °C. Among the nematodes used in experiments at 8 °C, no H. megidis and very few S. carpocapsae developed beyond the infective juvenile stage. Compared with H. megidis, S. carpocapsae invaded and killed G. mellonella larvae faster at 8 to 16 °C. By comparing invasion rates, differences in infectivity between the two nematode species were detected that could not be detected in conventional petri dish bioassays where mortality was measured after a specified period. Invasion of G. mellonella larvae by H. megidis was faster at 24 than at 16 °C.     

Damage Functions for Meloidogyne arenaria on Peanut

Microplot experiments were conducted in 1989 and 1990 to determine the relationship between yield of peanut (Arachis hypogaea) and inoculum density ofMeloidogyne arenaria race 1. Nine inoculum densities were used, ranging from 0-200 eggs/100 cm³ soil (1989) or from 0-100 eggs/100 cm³ (1990), and each density was replicated 10 times. In 1989, higher final densities (mean of 1,171 juveniles [J2]/100 cm³ soil) were obtained in plots inoculated with 0.5 to 50 eggs/100 cm³ soil than in plots inoculated with 100 to 200 eggs/100 cm³ (313 J2/100 cm³ soil). In 1990, final densities of M. arenaria reached high levels (≥ 1,111 J2/100 cm³ soil) in all inoculated plots. Pod yield and dry weight of foliage at harvest were negatively correlated (P ≤ 0.05) with inoculum density in both seasons. In 1989, the relationship between pod weight (y) and initial density (x) was described by Seinhorst''s equation, with y = 0.088 + 0.91(0.90)⁽x⁻¹⁾ and r² = 0.826. In 1990, the relationship was y = 0.22 + 0.78(0.97)⁽x⁻¹⁾ and r² = 0.794. These equations suggest tolerance limits of approximately 1 egg/100 cm³ soil, which may require specialized methods, such as bioassay, for detection.     

Expression analysis of heat shock protein genes during Aeromonas hydrophila infection in rohu,Labeo rohita,with special reference to molecular characterization of Grp78

Heat shock protein (Hsp) genes are stress-related genes that activate the host immune system during infection. Hsp genes expression in fish, studied during bacterial infections, is mostly confined to Hsp70 and Hsp90. The present study is an expression analysis of seven Hsp genes: Apg2, Hsp90, Hsp70, glucose-regulated protein 78 (Grp78), heat shock cognate 70 (Hsc70), Grp75, and Hsp30 during Aeromonas hydrophila infection in rohu, Labeo rohita. Forty-eight rohu juveniles were challenged with 3 × 10⁷ cfu bacteria per 20 g of body weight intraperitoneally. The expression of these genes was studied in infected liver, anterior kidney, and spleen tissues of rohu at different time periods: 0, 1, 3, 6, 12, 24, 48, 72 h, 7, and 15 days post-infection by qPCR. The Hsp gene modulation was greater in liver as compared to spleen and kidney tissues. Induced expression of Apg2, Hsp90, Grp78, Grp75, and Hsc70 was noticed during peak periods (3 to 24 h post-challenge) of bacterial infectivity. Hsp70 was found to be down-regulated during the process of infection. In contrast to the other six genes, Hsp30 showed a variable expression pattern in all three tissues. Grp78 was found to be the most highly (1,587-fold) expressed gene in liver at 12 h post-challenge. Further, molecular characterization of Grp78 revealed it to be a highly conserved Hsp gene, essential not only during infection but also during early developmental stages of rohu, and its expression was noticed in all organs studied except in gill tissues, which indicated its potential immune regulatory role during infection process.     

In vivo antipyretic,antiemetic, in vitro membrane stabilization,antimicrobial, and cytotoxic activities of different extracts from Spilanthes paniculata leaves

Background

The study was conducted to evaluate the in vitro antimicrobial activity, cytotoxic, and membrane stabilization activities, and in vivo antiemetic and antipyretic potentials of ethanolic extract, n-hexane and ethyl acetate soluble fractions of Spilanthes paniculata leaves for the first time widely used in the traditional treatments in Bangladesh.

Results

In antipyretic activity assay, a significant reduction (P < 0.05) was observed in the temperature in the mice tested. At dose 400 mg/kg-body weight, the n-hexane soluble fraction showed the effect (36.7 ± 0.63°C ) as like as the standard (dose 150 mg/kg-body weight) after 5 h of administration. Extracts showed significant (P < 0.001) potential when tested for the antiemetic activity compared to the standard, metoclopramide. At dose 50 mg/kg-body weight, the standard showed 67.23% inhibition, whereas n-hexane and ethyl acetate soluble fractions showed 37.53% and 24.93% inhibition of emesis respectively at dose 400 mg/kg-body weight. In antimicrobial activity assay, the n-hexane soluble fraction (400 μg/disc) showed salient activity against the tested organisms. It exerts highest activity against Salmonella typhi (16.9 mm zone of inhibition); besides, crude, and ethyl acetate extracts showed resistance to Bacillus cereus and Bacillus subtilis, and Vibrio cholera respectively. All the extracts were tested for lysis of the erythrocytes. At the concentration of 1mg/ml, ethanol extract, and n-hexane and ethyl acetate soluble fractions significantly inhibited hypotonic solution induced lysis of the human red blood cell (HRBC) (27.406 ± 3.57, 46.034 ± 3.251, and 30.72 ± 5.679% respectively); where standard drug acetylsalicylic acid (concentration 0.1 mg/ml) showed 77.276 ± 0.321% inhibition. In case of heat induced HRBC hemolysis, the plant extracts also showed significant activity (34.21 ± 4.72, 21.81 ± 3.08, and 27.62 ± 8.79% inhibition respectively). In the brine shrimp lethality bioassay, the n-hexane fraction showed potent (LC₅₀ value 48.978 μg/ml) activity, whereas ethyl acetate fraction showed mild (LC₅₀ value 216.77 μg/ml) cytotoxic activity.

Conclusions

Our results showed that the n-hexane extract has better effects than the other in all trials. In the context, it can be said that the leaves of S. paniculata possess remarkable pharmacological effects, and justify its folkloric use as antimicrobial, antipyretic, anti-inflammatory, and antiemetic agent. Therefore, further research may be suggested to find possible mode of action of the plant part.     

Thermal thresholds as predictors of seed dormancy release and germination timing: altitude-related risks from climate warming for the wild grapevine Vitis vinifera subsp. sylvestris

Background and Aims

The importance of thermal thresholds for predicting seed dormancy release and germination timing under the present climate conditions and simulated climate change scenarios was investigated. In particular, Vitis vinifera subsp. sylvestris was investigated in four Sardinian populations over the full altitudinal range of the species (from approx. 100 to 800 m a.s.l).

Methods

Dried and fresh seeds from each population were incubated in the light at a range of temperatures (10–25 and 25/10 °C), without any pre-treatment and after a warm (3 months at 25 °C) or a cold (3 months at 5 °C) stratification. A thermal time approach was then applied to the germination results for dried seeds and the seed responses were modelled according to the present climate conditions and two simulated scenarios of the Intergovernmental Panel on Climate Change (IPCC): B1 (+1·8 °C) and A2 (+3·4 °C).

Key Results

Cold stratification released physiological dormancy, while very few seeds germinated without treatments or after warm stratification. Fresh, cold-stratified seeds germinated significantly better (>80 %) at temperatures ≥20 °C than at lower temperatures. A base temperature for germination (T_b) of 9·0–11·3 °C and a thermal time requirement for 50 % of germination (θ₅₀) ranging from 33·6 °Cd to 68·6 °Cd were identified for non-dormant cold-stratified seeds, depending on the populations. This complex combination of thermal requirements for dormancy release and germination allowed prediction of field emergence from March to May under the present climatic conditions for the investigated populations.

Conclusions

The thermal thresholds for seed germination identified in this study (T_b and θ₅₀) explained the differences in seed germination detected among populations. Under the two simulated IPCC scenarios, an altitude-related risk from climate warming is identified, with lowland populations being more threatened due to a compromised seed dormancy release and a narrowed seed germination window.     

Comparative Response of Alfalfa to Pratylenchus penetrans Populations

Four populations of Pratylenchus penetrans did not differ (P > 0.05) in their virulence or reproductive capability on Lahontan alfalfa. There was a negative relationship (r = -0 .7 9 ) between plant survival and nematode inocula densities at 26 ± 3 C in the greenhouse. All plants survived at an inoculum level (Pi) of 1 nematode/cm³ soil, whereas survival rates were 50 to 55% at 20 nematodes/cm³ soil. Alfalfa shoot and root weights were negatively correlated (r = - 0.87; P < 0.05) with nematode inoculum densities. Plant shoot weight reductions ranged from 13 % at Pi 1 nematode/cm³ soil to 69% for Pi 20 nematodes/cm³ soil, whereas root weight reductions ranged from 17% for Pi 1 nematode/cm³ soil to 75% for Pi 20 nematodes/cm³ soil. Maximum and minimum nematode reproduction (Pf/Pi) for the P. penetrans populations were 26.7 and 6.2 for Pi 1 and 20 nematodes/cm³ soil, respectively. There were negative correlations between nematode inoculum densities and plant survival (r = 0.84), and soil temperature and plant survival (r = -0 .7 8 ). Nematode reproduction was positively correlated to root weight (r = 0.89).     

First Report of Korean Cyst Nematode,Heterodera koreana,Parasitic on Bamboo,Phyllostachys nigra,from Iran

Bamboo is grown sporadically in the north of Iran and is confined to very limited areas. The history of growing bamboo was to some extent simultaneous with the entrance, commencement, and growth of the tea industry in the north about a century ago. The bamboo was used for making baskets to transfer the harvested tea foliage from farm to the factory and other linked functions. A main area allocated for bamboo growing is located in Lahidjan Agricultural Research Station (LARS) in the north of Iran, where several species of bamboo were cultivated in an area of 5 ha. The species include five species of Phyllostachys (viz., P. aurea, P. bambusoides, P. decora, P. nigra, P. vivax) and one species of Arundinaria gigantean, Pleioblastus fortune, and Semiarundinaria fastuosa; however, only P. aurea and P. nigra have been precisely identified. A survey on plant parasitic nematodes associated with bamboo mainly on P. nigra in LARS revealed second-stage juveniles of cyst forming nematode in soil samples. Further analysis of root and soil samples led to recovery of a cyst nematode belonging to the genus Heterodera and the Afenestrata group. Cysts, vulval cone, and second-stage juveniles were studied for morphological and morphometric features. The classical identification was followed by amplification of the ribosomal RNA-ITS region and the D2-D3 expansion segments of 28S large-subunit rRNA gene; the amplified fragments were sequenced, edited, and compared with those of the corresponding published gene sequences. New D2-D3 and rRNA-ITS gene sequences were deposited in the GenBank database under the accession numbers {"type":"entrez-nucleotide","attrs":{"text":"KR818910","term_id":"924272655","term_text":"KR818910"}}KR818910 and {"type":"entrez-nucleotide","attrs":{"text":"KR818911","term_id":"924272662","term_text":"KR818911"}}KR818911, respectively. Based on the morphological and molecular data, the species of the cyst-forming nematode was identified as H. koreana (Vovlas et al., 1992; Mundo-Ocampo et al., 2008). The body contour of cysts was mainly subspherical, vey often with irregular shape (Fig. 1A), yellowish to light brown, thin cuticle with fine zigzag pattern, without fenestration, lacking bulla, and underbridge. Vulval lips protruded, cuticular pattern of vulval cone with a tuberculate area (Fig. 2B), and vagina embedded into vulval lips. The second-stage juveniles cylindrical and slender, hemispherical cephalic framework, with three lines in lateral field, well-developed rounded stylet knobs, tail conoid tapring to fine rounded terminus, phasmids posterior to anus. The cyst measurements were (n = 21) length 502 ± 70 (420 to 640) µm; width = 408 ± 60 (320 to 520) µm; length/width = 1.23 ± 0.09 (1.07 to 1.5) µm. The morphometric characters of vulval cone were measured (n = 7): fenestral length = 62.4 ± 6.5 (51 to 71) µm; fenestral width = 50.7 ± 3.2 (45 to 54) µm; vulval slit = 51.9 ± 4.3 (46 to 59) µm; distance from vulva to anus = 51.3 ± 4.4 (43 to 56) µm. Second-stage juveniles showed the following morphometric characters (n = 14): L = 455 ± 11.3 (437 to 472) µm; a = 29.9 ± 0.9 (28.3 to 31.5); b΄ = 2.7 ± 0.4 (2.2 to 3.5); c = 7.4 ± 0.9 (6 to 8.9); ć = 6.1 ± 0.4 (5.1 to 6.7); lip region height = 3 µm; lip region width = 7.5 ± 0.5 (7 to 8) µm; stylet length = 18.1 ± 0.5 (17 to 19) µm; anterior end to median bulb = 72.2 ± 1.7 (70 to 75) µm; anterior end to secretory-excretory pore = 99.7 ± 2.5 (96 to 103) µm; maximum body width = 15.2 ± 0.4 (15 to 16) µm; body width at anus = 10.1 ± 1 (8 to 11) µm; tail length = 62.0 ± 6.9 (51 to 74) µm; hyaline part of tail = 44.0 ± 1.8 (40 to 47) µm. The egg measurements for 11 individuals were length = 102.5 ± 7.9 (93 to 119) µm; width = 39.3 ± 4.2 (33 to 46) µm; length/width = 2.6 ± 0.3 (2.0 to 3.1). The morphology, morphometric characters and molecular data of the population of H. koreana isolated from bamboo in Iran are in agreement with those previously reported for this species (Vovlas et al., 1992; Mundo-Ocampo et al., 2008). At present, five species of Heterodera belonging to the Cyperi and Afenestrata groups were reported from bamboo, H. bamboosi (Kaushal and Swarup, 1988; Wouts and Baldwin, 1998) on Bambusa sp. from India; H. koreana on P. pubescence, P. aurea, and P. nigra from South Korea and the United States; and H. hainanensis (Zhuo et al., 2013), H. fengi (Wang et al., 2013), and H. guangdongensis (Zhuo et al., 2014) on P. pubescence from China; thus showing host suitability of bamboo for at least five species of cyst-forming nematodes. A greenhouse test performed by planting rice seed cv. Hashemi in soil containing H. koreana showed successful multiplication of Korean cyst nematode on rice seedlings after 2 mon. The exact date of the establishment of bamboo plantation in LARS is not precisely clear, but it indicates that the Korean cyst nematode was most likely brought with the imported bamboo seedlings from unknown origin several decades ago. According to our best knowledge, this is the first report of occurrence of H. koreana from Iran. So far the Korean cyst nematode was reported from South Korea, Thailand, and the United States, Florida (from nurseries); this study includes the distribution of this cyst-forming nematode in Iran and expands the information of the occurrence of H. koreana for the world.     

Effectiveness of a Hot Water Drench for the Control of Foliar Nematodes Aphelenchoides fragariae in Floriculture

Effectiveness of a hot water drench for the control of Aphelenchoides fragariae infesting hosta (Hosta sp.) and ferns (Matteuccia pensylvanica) was studied. Drenching with hot water at 70 °C and 90 °C in October reduced (P < 0.05) A. fragariae in the soil but not in the leaves relative to the control (25 °C) 300 days after treatment (DAT). Plants drenched with 90 °C water had lower numbers of nematode-infected leaves per plant than those treated with 25 °C and 70 °C water (P < 0.05). Hot water treatments had no adverse effect on the growth parameters of hosta. Boiling water (100 °C) applied once a month for 3 consecutive months (April, May, June) consistently reduced the number of infected leaves and the severity of infection relative to the control 150 DAT in hosta but not in ferns (P < 0.05). Boiling water (100 °C) caused a 67% reduction in A. fragariae population in hosta leaves, 50% in fern fronds, and 61% to 98% in the soil over the control 150 DAT. A boiling water drench had no effect on the fern growth but caused 49% and 22% reduction in the number and size of hosta leaves, respectively, over the control in 2002. We conclude that 90 °C water soil drench in the autumn or early spring could prove effective in managing foliar nematodes on hosta in nurseries and landscapes.     

Importance of Temperature in the Pathology of Meloidogyne hapla and M. chitwoodi on Legumes

Effects of temperatures on the host-parasite relationships were studied for three legume species and four populations of root-knot nematodes from the western United States. The nematode populations were Meloidogyne hapla from California (MHCA), Utah (MHUT), and Wyoming (MHWY), and a population of M. chitwoodi from Utah (MCUT). The legumes were milkvetch (Astragalus cicer), alfalfa (Medicago sativa), and yellow sweet clover (Melilotus officinalis). All milkvetch plants survived inoculation with all nematode populations, while alfalfa and yellow sweet clover were more susceptible. On yellow sweet clover, MHCA was most pathogenic at 30 °C based on suppression of shoot growth while MHUT, MHWY, and MCUT were most pathogenic at 25 °C. All nematode populations suppressed growth of yellow sweet clover more than growth of milkvetch and alfalfa. The reproductive factor (Rf = final nematode population/initial nematode population) of MHCA was positively correlated (r = 0.83) with temperature between 15 °C and 30 °C. The greatest Rf occurred on alfalfa inoculated with MHCA at 30 °C. The Rf of MHUT, MHWY, and MCUT were positively correlated (r= 0.76, r= 0.78, and r= 0.73, respectively) with temperature between 15 °C and 25 °C. The Rf values of MHUT and MHWY were similar on all species and exceeded the Rf of MCUT at all temperatures (P < 0.05).     

Against the odds: complete outcrossing in a monoecious clonal seagrass Posidonia australis (Posidoniaceae)

Background and Aims

Seagrasses are marine, flowering plants with a hydrophilous pollination strategy. In these plants, successful mating requires dispersal of filamentous pollen grains through the water column to receptive stigmas. Approximately 40 % of seagrass species are monoecious, and therefore little pollen movement is required if inbreeding is tolerated. Outcrossing in these species is further impacted by clonality, which is variable, but can be extensive in large, dense meadows. Despite this, little is known about the interaction between clonal structure, genetic diversity and mating systems in hydrophilous taxa.

Methods

Polymorphic microsatellite DNA markers were used to characterize genetic diversity, clonal structure, mating system and realized pollen dispersal in two meadows of the temperate, monoecious seagrass, Posidonia australis, in Cockburn Sound, Western Australia.

Key Results

Within the two sampled meadows, genetic diversity was moderate among the maternal shoots (R = 0·45 and 0·64) and extremely high in the embryos (R = 0·93–0·97). Both meadows exhibited a highly clumping (or phalanx) structure among clones, with spatial autocorrelation analysis showing significant genetic structure among shoots and embryos up to 10–15 m. Outcrossing rates were not significantly different from one. Pollen dispersal distances inferred from paternity assignment averaged 30·8 and 26·8 m, which was larger than the mean clone size (12·8 and 13·8 m).

Conclusions

These results suggest highly effective movement of pollen in the water column. Despite strong clonal structure and moderate genetic diversity within meadows, hydrophilous pollination is an effective vector for completely outcrossed offspring. The different localized water conditions at each site (highly exposed conditions vs. weak directional flow) appear to have little influence on the success and pattern of successful pollination in the two meadows.