Delayed Symptom Development Research Articles

Nervonic Acid Attenuates Accumulation of Very Long-Chain Fatty Acids and is a Potential Therapy for Adrenoleukodystrophy.

Adrenoleukodystrophy (ALD) is an X-linked inherited peroxisomal disorder due to mutations in theALD protein and characterized by accumulation of very long-chain fatty acids (VLCFA), specifically hexacosanoic acid (C26:0). This can trigger other pathological processes such as mitochondrial dysfunction, oxidative stress, and inflammation, which if involves the brain tissues can result in a lethal form of the disease called childhood cerebral ALD. With the recent addition of ALD to the Recommended Uniform Screening Panel, there is an increase in the number of individuals who are identified with ALD. However, currently, there is no approved treatment for pre-symptomatic individuals that can arrest or delay symptom development. Here, we report our observations investigating nervonic acid, a monounsaturated fatty acid as a potential therapy for ALD. Using ALD patient-derived fibroblasts, we examined whether nervonic acid can reverse VLCFA accumulation similar to erucic acid, the active ingredient in Lorenzo's oil, a dietary intervention believed to alter disease course. We have shown that nervonic acid can reverse total lipid C26:0 accumulation in a concentration-dependent manner in ALD cell lines. Further, we show that nervonic acid can protect ALD fibroblasts from oxidative insults, presumably by increasing intracellular ATP production. Thus, nervonic acid can be a potential therapeutic for individuals with ALD, which can alter cellular biochemistry and improve its function.

Transgenic tomato expressing an oxalate decarboxylase gene from Flammulina sp. shows increased survival to Moniliophthora perniciosa

Witches’ broom disease which affects cacao tree (Theobroma cacao L.) is caused by the hemibiotrophic fungus Moniliophthora perniciosa. Studies of the cacao-M. perniciosa interaction showed that the pathogenicity of M. perniciosa is associated to the presence of oxalic acid (OA). In some organisms, OA can be degraded into formate and CO2 by the oxalate decarboxylase (OXDC) enzyme. Here, we used the oxdc gene from Flammulina velutipes to generate transgenic tomato plants as a potential strategy to control M. perniciosa infection. Three transgenic T1 lines expressing the oxdc gene were obtained and two of them (P4 and P16) presented a significant delay in symptom development and higher survival percentage when inoculated with M. perniciosa in comparison to the non-transformed wild-type (WT) plants. Moreover, the P16 line test showed a decreased production of H2O2 in the presence of OA in comparison to the WT, as evidenced by the 3,3′-diaminobenzidine test. These results indicate that the P16 transgenic line is able to break down OA leading to normal plant development with few symptoms even when infected by M. perniciosa. Phenotypic and histological analysis showed differences between WT and transgenic plants. The amount of fungus hyphae was lower with thinner thickness in the transgenic plants. This study evidences of the reduction of witches’ broom disease progression by the presence of the oxdc gene leading to the plant survival.

Roles of two distinct alphasatellites modulating geminivirus pathogenesis

BackgroundAlphasatellites are small coding DNA satellites frequently associated with a begomovirus/betasatellite complex, where they are known to modulate virulence and symptom development. Two distinct alphasatellites, namely, Cotton leaf curl Multan alphasatellite (CLCuMuA), and Gossypium darwinii symptomless alphasatellite (GDarSLA) associated with Cotton leaf curl Multan virus-India (CLCuMuV-IN) and Ludwigia leaf distortion betasatellite (LuLDB) were found to be associated with yellow mosaic disease of hollyhock (Alcea rosea) plants. In this study, we show that alphasatellites CLCuMuA and GDarSLA attenuate and delay symptom development in Nicotiana benthamiana. The presence of either alphasatellites reduce the accumulation of the helper virus CLCuMuV-IN. However, the levels of the associated betasatellite, LuLDB, remains unchanged. These results suggest that the alphasatellites could contribute to the host defence and understanding their role in disease development is important for developing resistance strategies.MethodsTandem repeat constructs of two distinct alphasatellites, namely, CLCuMuA and GDarSLA associated with CLCuMuV-IN and LuLDB were generated. N. benthamiana plants were co-agroinoculated with CLCuMuV and its associated alphasatellites and betasatellite molecules and samples were collected at 7, 14 and 21 days post inoculation (dpi). The viral DNA molecules were quantified in N. benthamiana plants by qPCR. The sequences were analysed using the MEGA-X tool, and a phylogenetic tree was generated. Genetic diversity among the CLCuMuA and GDarSLA was analysed using the DnaSP tool.ResultsWe observed a reduction in symptom severity and accumulation of helper virus in the presence of two alphasatellites isolated from naturally infected hollyhock plants. However, no reduction in the accumulation of betasatellite was observed. The phylogenetic and genetic variability study revealed the evolutionary dynamics of these distinct alphasatellites , which could explain the role of hollyhock-associated alphasatellites in plants.ConclusionsThis study provides evidence that alphasatellites have a role in symptom modulation and suppress helper virus replication without any discernible effect on the replication of the associated betasatellite.

Exogenous Application of Elicitors Induces Biochemical Alterations and Develops Tolerance against Yellow Mosaic Disease in Mungbean

Mungbean (Vigna radiata) is seriously affected by mungbean yellow mosaic disease (MYMD) caused by Mungbean yellow mosaic India virus (MYMIV) in the Indian subcontinent. The present study was conducted to evaluate the effectiveness of salicylic acid (SA) and benzothiadiazole (BTH) for the management of MYMD and to find their role in inducing alteration in different biochemical parameters in susceptible mungbean genotype VC3061A. Exogenous application of the elicitors resulted in delayed symptom development and reduced disease severity (DS). The severity index (SI) was higher on positive control plants while the minimum was observed in post combined application of BTH+SA, followed by BTH and SA application. Total phenolic contents (TPC) and malondialdehyde (MDA) increased significantly in virus inoculated plants of all treatments as compared to their healthy controls. SOD activity was increased significantly in BTH+SA treated plants but decreased in disease control and BTH treated virus inoculated plants. A significant decrease in catalase (CAT) activity, while an increase in peroxidase (POD) was observed in BTH+SA, treated virus inoculated plants. Protease and esterase activity were significantly increased in SA treated virus inoculated plants. Plant pigments exhibited decreased concentration in virus inoculated plants compared to non-inoculated plants under all the treatments except SA treated plants. Enhanced or suppressed levels of antioxidants suggest an association between constitutive induced levels of these enzymes. In this study, we also report for the first time the protein profiling of mungbean genotype VC3061A after the exogenous application of different combinations of elicitors. Proteomic analyses revealed the expression of two proteins phosphatase 2C 16-like isoform and capsid protein after MYMIV inoculation in SA and BTH+SA treated plants which may trigger signal transduction pathway and consequently induces resistance against MYMIV in V. radiata by activating PR protein.

Relationship Between Tumor Response and Tumor-Related Symptoms in RAS Wild-Type Metastatic Colorectal Cancer: Retrospective Analyses From 3 Panitumumab Trials

BackgroundThere is no standardized assessment of symptomatic events in metastatic colorectal cancer (mCRC) despite disease symptoms that affect treatment decisions. Data from 3 first-line panitumumab in mCRC trials were retrospectively analyzed to assess whether early tumor shrinkage (ETS) and depth of response (DpR) were associated with time to occurrence of tumor-related symptoms. Patients and MethodsPatients with RAS wild-type mCRC from PRIME, PEAK, and Study 314 were included. ETS was defined as a reduction of ≥ 30% in the sum of the longest diameters of lesions at 8 weeks. DpR was calculated as maximum percentage change in tumor size from baseline to nadir. The proportion of patients who developed symptoms (including a composite symptomatic endpoint) during study treatment was calculated. This study was registered at ClinicalTrials.gov as PRIME (NCT00364013), PEAK (NCT00819780), and Study 314 (NCT00508404). ResultsOverall, data of 659 patients were analyzed. Onset of symptoms was delayed in patients with ETS ≥ 30% versus ETS < 30% and in patients with greater DpR. In patients with symptoms at baseline who experienced ETS ≥ 30%, overall survival was similar to that seen for patients without symptoms at baseline. ConclusionBoth ETS and DpR were associated with delayed onset of symptoms in RAS wild-type mCRC patients. Treatments with high cytoreductive potential may delay symptom development.

The Effect of Silica (SiO2) to the Severity of Yellow Leaf Curl Disease on Chili Pepper

Yellow leaf curl disease of chili pepper caused by Pepper yellow leaf curl virus (PYLCV) has been reported as an important disease in Java and Bali. Disease severity reached 80−100% and it may cause significant yield losses. In order to reduce the negative impact of synthetic insecticides, silica application was evaluated for its potency to suppress the disease. A greenhouse experiment was conducted using randomly block design with 2 factors: PYLCV isolate (Java and Bali) and silica (SiO2) treatment (with and without). Parameters observed were disease symptoms, incubation period, disease incidence and severity, and total silica level. The symptoms of virus infection in Pelita 8 and Seret cultivars were yellow mosaic, leaf curl, green mosaic, dwarf, and cupping upward or downward. A Specific DNA fragment of 912 bp was successfully amplified from 4 samples. Four sequences were obtained and further analysis showed their highest homology, i.e. 96% and 97% with Pepper yellow leaf curl Indonesia virus-Java (PYLCIV-Java) (JX416180) and PYLCIV-KrthAl (LC381274), respectively. Infection by different virus isolates did not affect disease severity significantly. The application of silica was able to delay symptom development and to suppress the severity of the disease in the range of 16.67−30.33%. Silica application on the soil increased the total content of silica in the plants. However, a further experiment is required to understand the mode of action of silica in inducing plant resistance to the pathogen.

Retraction: Detection and Functional Characterization of a 215 Amino Acid N-Terminal Extension in the Xanthomonas Type III Effector XopD.

During evolution, pathogens have developed a variety of strategies to suppress plant-triggered immunity and promote successful infection. In Gram-negative phytopathogenic bacteria, the so-called type III protein secretion system works as a molecular syringe to inject type III effectors (T3Es) into plant cells. The XopD T3E from the strain 85-10 of Xanthomonas campestris pathovar vesicatoria (Xcv) delays the onset of symptom development and alters basal defence responses to promote pathogen growth in infected tomato leaves. XopD was previously described as a modular protein that contains (i) an N-terminal DNA-binding domain (DBD), (ii) two tandemly repeated EAR (ERF-associated amphiphillic repression) motifs involved in transcriptional repression, and (iii) a C-terminal cysteine protease domain, involved in release of SUMO (small ubiquitin-like modifier) from SUMO-modified proteins. Here, we show that the XopD protein that is produced and secreted by Xcv presents an additional N-terminal extension of 215 amino acids. Closer analysis of this newly identified N-terminal domain shows a low complexity region rich in lysine, alanine and glutamic acid residues (KAE-rich) with high propensity to form coiled-coil structures that confers to XopD the ability to form dimers when expressed in E. coli. The full length XopD protein identified in this study (XopD1-760) displays stronger repression of the XopD plant target promoter PR1, as compared to the XopD version annotated in the public databases (XopD216-760). Furthermore, the N-terminal extension of XopD, which is absent in XopD216-760, is essential for XopD type III-dependent secretion and, therefore, for complementation of an Xcv mutant strain deleted from XopD in its ability to delay symptom development in tomato susceptible cultivars. The identification of the complete sequence of XopD opens new perspectives for future studies on the XopD protein and its virulence-associated functions in planta.

Atypical presentations of MERS-CoV infection in immunocompromised hosts

During the 2015 Korean MERS outbreak, we experienced atypical presentations of MERS-CoV infections in three immunocompromised hosts that warranted exceptional management. Case 1 showed delayed symptom development after a four-day asymptomatic period, Case 2 experienced a 20-day incubation period, and Case 3 exhibited persistent viral shedding without clinical deterioration. Recognizing these exceptions is extremely important in the management of MERS-CoV-exposed or -infected patients and for control of potential MERS outbreaks.

The Xanthomonas campestris pv. vesicatoria Type-3 Effector XopB Inhibits Plant Defence Responses by Interfering with ROS Production.

The bacterial pathogen Xanthomonas campestris pv. vesicatoria 85–10 (Xcv) translocates about 30 type-3 effector proteins (T3Es) into pepper plants (Capsicum annuum) to suppress plant immune responses. Among them is XopB which interferes with PTI, ETI and sugar-mediated defence responses, but the underlying molecular mechanisms and direct targets are unknown so far. Here, we examined the XopB-mediated suppression of plant defence responses in more detail. Infection of susceptible pepper plants with Xcv lacking xopB resulted in delayed symptom development compared to Xcv wild type infection concomitant with an increased formation of salicylic acid (SA) and expression of pathogenesis-related (PR) genes. Expression of xopB in Arabidopsis thaliana promoted the growth of the virulent Pseudomonas syringae pv. tomato (Pst) DC3000 strain. This was paralleled by a decreased SA-pool and a lower induction of SA-dependent PR gene expression. The expression pattern of early flg22-responsive marker genes indicated that MAPK signalling was not altered in the presence of XopB. However, XopB inhibited the flg22-triggered burst of reactive oxygen species (ROS). Consequently, the transcript accumulation of AtOXI1, a ROS-dependent marker gene, was reduced in xopB-expressing Arabidopsis plants as well as callose deposition. The lower ROS production correlated with a low level of basal and flg22-triggered expression of apoplastic peroxidases and the NADPH oxidase RBOHD. Conversely, deletion of xopB in Xcv caused a higher production of ROS in leaves of susceptible pepper plants. Together our results demonstrate that XopB modulates ROS responses and might thereby compromise plant defence.

Breast cancer method of detection, stage at diagnosis, and delay in treatment in La Libertad province, Peru.

15 Background: The majority of breast cancer deaths occur in low- and middle-income countries, as a result of late stage disease presentation and inadequate access to diagnosis and treatment. Delay from development of symptomatology to initiation of treatment is associated with more advanced breast cancer, and delays greater than three months have been associated with reduced survival. We investigated method of detection, disease stage, and time to diagnosis and treatment in breast cancer patients in Peru. Methods: This investigation was conducted at the Instituto Regional de Enfermedades Neoplasicas del Norte, in Trujillo, Peru. All women with a pathologic or clinical diagnosis of breast cancer who visited a breast surgeon from February-May 2015 were eligible to participate. Trained personnel conducted individual patient interviews in Spanish, utilizing a validated breast cancer delays questionnaire. Results: Of the 159 women who qualified for inclusion, 113 (71%) agreed to participate in the study. Mean age was 54 years (range 30-85). Patients lived an average of 3 hours from the oncology institute (range 0-36). Most households earned less than minimum wage, and most (66%) were covered by Seguro Integral de Salud, the government-funded medical insurance for citizens with limited financial resources. One hundred and five (93%) participants reported initially detecting their breast cancer as a result of symptoms. One cancer (1%) was detected during screening clinical breast examination, and 7 (6%) by screening mammography. Ninety-three patients had available stage at time of diagnosis, with the following distribution: stage 0- 2%, stage 1-3%, stage 2-44%, stage 3-48%, and stage 4-3%. Based on patient report, mean patient delay (symptom development to first medical visit at any facility) was 211 days. Mean provider delay (first medical visit until treatment initiation) was 241 days. Mean total delay (symptom development to treatment initiation) was 407 days. Conclusions: Almost all study participants initially detected their breast cancer as a result of symptoms. More than half presented with stage 3 or 4 disease. Average delay from symptom onset to start of treatment was greater than one year.

Asian Foxtail (Uraria crinita), a New Host for Sclerotium rolfsii from Taiwan.

Asian foxtail (Uraria crinita (L.) Desv. ex DC.) is an herb cultivated for the use of roots and stems in Taiwanese cuisine. In September 2013, symptoms of leaf blight and basal rot were observed on U. crinita in a commercial field in Longjing District, Taichung, Taiwan, at an incidence of approximately 20%. White mycelia and brown sclerotia formed on the surfaces of the basal stems. The infected plant gradually wilted and eventually died. Diseased lower stem tissues were surface sterilized in 0.6% NaOCl, rinsed with sterile distilled water, and transferred to potato dextrose agar plates. The cultures were incubated at 25°C in the dark. The radial mycelial growth was 9.0 mm/day during the first 4 days, and the diameter of mature sclerotia was 1.76 mm following 3 weeks of incubation. The internal transcribed spacer (ITS) sequence of the isolate was amplified by PCR using the primers ITS5 and ITS4 (2). The amplicon was cloned, sequenced, and deposited in GenBank (Accession No. KJ677121). The sequence similarity was 99% compared with that of Sclerotium rolfsii Sacc. from Spain (GU080230) (1). Based on the characteristics, the fungus was identified as S. rolfsii. The fungal isolate (BCRC FU30230) was deposited in the Bioresource Collection and Research Center, Hsinchu, Taiwan. Pathogenicity tests were conducted on six 2-month-old potted U. crinita plants in a greenhouse. Prior to infesting the plant, fungal inoculum of S. rolfsii BCRC FU30230 was prepared by inoculating the isolate on autoclaved rice (rice/water/dextrose = 50:50:1) in a flask. After 20 days incubation at room temperature, rice colonized by S. rolfsii was placed near the base of the plants (approximately 30 g/plant) in the greenhouse. Sterile rice applied to an equal number of plants served as negative controls. All inoculated plants developed blight symptoms with mycelia and sclerotia produced near the bases of each seedling 1 week after inoculation at an average temperature of 26°C. The control plants remained healthy. The pathogen re-isolated from the inoculated plants was morphologically identical to the original isolate. The pathogenicity test was repeated by inoculated healthy plants with reduced inoculum (five granules/plant). A delay of symptom development was observed and similar results were obtained. To our knowledge, this is the first report of Sclerotium rot on U. crinita in Taiwan, and the first report on U. crinita as a host for S. rolfsii.

Genotypes of Fraxinus excelsior with different susceptibility to the ash dieback pathogen Hymenoscyphus pseudoalbidus and their response to the phytotoxin viridiol – A metabolomic and microscopic study

Eight European ash (Fraxinus excelsior) genotypes with different known susceptibility to Hymenoscyphus pseudoalbidus were tested against the phytotoxin viridiol and their response described at the microscopic and metabolomic level. All ash genotypes were sensitive to the toxin and necrosis was detectable after 24h. Among the three viridiol concentrations used in the experiment, the lowest concentration (14.7μM) yielded markedly lower mean damage scores compared to those resulting from seedlings tested at higher dosages. The highest damage scores were associated with the susceptible ash clones S-101, S-106 and S-125, but also with resistant clone R-104. Three resistant clones (R-131, R-121, and R-118) had lower mean damage scores compared to susceptible clones. Wilting of leaves was more common 48h after treatment and more pronounced on seedlings with high damage scores. The resulting lesions generally lacked browning of tissue and displayed only surface disruption of cells in direct contact with the toxin. A delay in symptom development was evident on all five resistant clones tested with the two higher concentrations of viridiol. LC-HRMS and MS/MS analyses of ash seedling extracts suggest several secoiridoid compounds as well as compounds related to abscisic acid (ABA) to be produced in response to viridiol. ABA-cysteine and xanthoxin were found at significantly higher concentrations in susceptible clones compared to resistant clones after treatment with viridiol, suggesting a primary role of ABA in response to stress. The results observed in this study suggest that genetic resistance to H. pseudoalbidus among ash genotypes may be explained, in part, by the varied response to phytotoxins produced by the fungus.

Modified primers for the identification of nonpathogenic Fusarium oxysporum isolates that have biological control potential against Fusarium wilt of cucumber in Taiwan.

Previous investigations demonstrated that Fusarium oxysporum (Fo), which is not pathogenic to cucumbers, could serve as a biological control agent for managing Fusarium wilt of cucumber caused by Fo f. sp. cucumerinum (Foc) in Taiwan. However, thus far it has not been possible to separate the populations of pathogenic Fo from the nonpathogenic isolates that have biological control potential through their morphological characteristics. Although these two populations can be distinguished from one another using a bioassay, the work is laborious and time-consuming. In this study, a fragment of the intergenic spacer (IGS) region of ribosomal DNA from an Fo biological control agent, Fo366, was PCR-amplified with published general primers, FIGS11/FIGS12 and sequenced. A new primer, NPIGS-R, which was designed based on the IGS sequence, was paired with the FIGS11 primer. These primers were then evaluated for their specificity to amplify DNA from nonpathogenic Fo isolates that have biological control potential. The results showed that the modified primer pair, FIGS11/NPIGS-R, amplified a 500-bp DNA fragment from five of seven nonpathogenic Fo isolates. These five Fo isolates delayed symptom development of cucumber Fusarium wilt in greenhouse bioassay tests. Seventy-seven Fo isolates were obtained from the soil and plant tissues and then subjected to amplification using the modified primer pair; six samples showed positive amplification. These six isolates did not cause symptoms on cucumber seedlings when grown in peat moss infested with the isolates and delayed disease development when the same plants were subsequently inoculated with a virulent isolate of Foc. Therefore, the modified primer pair may prove useful for the identification of Fo isolates that are nonpathogenic to cucumber which can potentially act as biocontrol agents for Fusarium wilt of cucumber.

First Report of Black Spots on Avocado Fruit Caused by Neofusicoccum parvum in Mexico.

Avocado (Persea americana L.) production for export markets has increased in Mexico during the past 10 years. The production system, however, is affected by several sanitation factors, including diseases. During the spring of 2009, smooth, black, circular spots were noted on the surface of avocado fruit. A study was conducted during the winter of 2010 to ascertain the etiology and identify the fungus associated with black spot symptoms on avocado fruit in orchards of Nuevo Parangaricutiro County (19°25'00″ and 102°07'43″) in Michoacan, Mexico. Several fungal isolates were obtained on potato dextrose agar (PDA) from the margin of lesions on immature fruit. The internal transcribed spacer region (ITS) of the rDNA from representative isolates was sequenced with universal primers ITS5 and ITS4 (2). BLAST searches in GenBank showed 100% similarity of the nucleotide sequences with Neofusicoccum parvum (Pennycook & Samuels) Crous, Slippers & A.J.L. Phillips, GenBank Accession Nos. GU188001 to GU188007 and GU187985 to GU187987. A representative nucleotide sequence of this region was deposited in GenBank under the Accession No. JN203129. Strains of N. parvum produced aerial and compact mycelium on acidified PDA, the anamorph state of Botryosphaeria parva. Mycelium was initially white, turning gradually gray to black. Conidia were one celled, hyaline, ellipsoidal to fusiform, externally smooth, thin walled, nonseptate, with one or two septa with age, and an average length and width of 14.5 (9.5 to 19) × 5.8 (4.0 to 7.2) μm (n = 100). Pathogenicity tests were conducted with six avocado fruit cv. Hass. Fruit were inoculated at three evenly spaced locations on the fruit surface, either by wounding the tissue with a needle that had been dipped in a conidial mass from an 8-day-old monoconidial culture of N. parvum strain CIAD-021-11 or by placing 5 μl of 1 × 106 conidia ml-1 suspension on each inoculation site. Inoculated fruit were maintained in a moist chamber at 25°C for 2 weeks. Black lesions appeared on all wounded sites 2 days postinoculation (dpi) and on unwounded sites 4 dpi. The delay of symptom development was likely due to penetration through the lenticels, which took longer to initiate infection. No symptoms were observed in the control fruit. The pathogen was reisolated from the lesions of all inoculated fruit, thus fulfilling Koch's postulates. The results confirmed the pathogenic potential of this fungus and indicated its possible involvement in the etiology of black spot on avocado fruit. N. parvum is a cosmopolitan, plurivorous pathogen causing disease in several hosts of economic importance, such as grapes and kiwi, as well as causing stem-end rot of avocado fruit in New Zealand (1) and avocado twigs in Spain (3). To our knowledge, this is the first report of N. parvum causing black spots on avocado fruit in Mexico.

Scabies: A Review of Diagnosis and Management Based on Mite Biology

Scabies is a contagious parasitic dermatitis that is a significant cause of morbidity, especially outside of the United States. Scabies is diagnosed most often by correlating clinical suspicion with the identification of a burrow. Although scabies should be on the differential for any patient who presents with a pruritic dermatosis, clinicians must consider a wide range of diagnostic possibilities. This approach will help make scabies simultaneously less over- and underdiagnosed by clinicians in the community. Atypical or otherwise complex presentations may necessitate the use of more definitive diagnostic modalities, such as microscopic examination of KOH prepared skin scrapings, high-resolution digital photography, dermoscopy, or biopsy. Scabies therapy involves making the correct diagnosis, recognizing the correct clinical context to guide treatment of contacts and fomites, choosing the most effective medication, understanding how to use the agent properly, and following a rational basis for when to use and reuse that agent. Although the development of new therapeutic agents is always welcome, tried and true treatments are still effective today. Permethrin is the gold standard therapy, with malathion being an excellent topical alternative. Ivermectin is an effective oral alternative that is especially useful in crusted scabies, patients who are bed ridden, and in institutional outbreaks. Despite the availability of effective therapeutics, treatment failures still occur, mostly secondary to application error (ie, failure to treat the face and scalp or close contacts, failure to reapply medication) or failure to decontaminate fomites. Because increasing resistance to scabies treatments may be on the horizon, we propose that standard of care for scabies treatment should involve routine treatment of the scalp and face and re-treating patients at day 4 on the basis of the scabies life cycle to ensure more efficient mite eradication. Practitioners should attempt to treat all close contacts simultaneously with the source patient. To eradicate mites, all fomites should be placed in a dryer for 10 minutes on a high setting, furniture and carpets vacuumed, and nonlaunderables isolated for a minimum of 2 days, or, for those who wish to be rigorous, 3 weeks.

Detection and Functional Characterization of a 215 Amino Acid N-Terminal Extension in the Xanthomonas Type III Effector XopD

During evolution, pathogens have developed a variety of strategies to suppress plant-triggered immunity and promote successful infection. In Gram-negative phytopathogenic bacteria, the so-called type III protein secretion system works as a molecular syringe to inject type III effectors (T3Es) into plant cells. The XopD T3E from the strain 85-10 of Xanthomonas campestris pathovar vesicatoria (Xcv) delays the onset of symptom development and alters basal defence responses to promote pathogen growth in infected tomato leaves. XopD was previously described as a modular protein that contains (i) an N-terminal DNA-binding domain (DBD), (ii) two tandemly repeated EAR (ERF-associated amphiphillic repression) motifs involved in transcriptional repression, and (iii) a C-terminal cysteine protease domain, involved in release of SUMO (small ubiquitin-like modifier) from SUMO-modified proteins. Here, we show that the XopD protein that is produced and secreted by Xcv presents an additional N-terminal extension of 215 amino acids. Closer analysis of this newly identified N-terminal domain shows a low complexity region rich in lysine, alanine and glutamic acid residues (KAE-rich) with high propensity to form coiled-coil structures that confers to XopD the ability to form dimers when expressed in E. coli. The full length XopD protein identified in this study (XopD1-760) displays stronger repression of the XopD plant target promoter PR1, as compared to the XopD version annotated in the public databases (XopD216-760). Furthermore, the N-terminal extension of XopD, which is absent in XopD216-760, is essential for XopD type III-dependent secretion and, therefore, for complementation of an Xcv mutant strain deleted from XopD in its ability to delay symptom development in tomato susceptible cultivars. The identification of the complete sequence of XopD opens new perspectives for future studies on the XopD protein and its virulence-associated functions in planta.

Enhanced Glutathione Metabolism Is Correlated with Sulfur-Induced Resistance in Tobacco mosaic virus–Infected Genetically Susceptible Nicotiana tabacum Plants

Sulfur-induced resistance, also known as sulfur-enhanced defense (SIR/SED) was investigated in Nicotiana tabacum cv. Samsun nn during compatible interaction with Tobacco mosaic virus (TMV) in correlation with glutathione metabolism. To evaluate the influence of sulfur nutritional status on virus infection, tobacco plants were treated with nutrient solutions containing either sufficient sulfate (+S) or no sulfate (-S). Sufficient sulfate supply resulted in a suppressed and delayed symptom development and diminished virus accumulation over a period of 14 days after inoculation as compared with -S conditions. Expression of the defense marker gene PR-1a was markedly upregulated in sulfate-treated plants during the first day after TMV inoculation. The occurrence of SIR/SED correlated with a higher level of activity of sulfate assimilation, cysteine, and glutathione metabolism in plants treated with sulfate. Additionally, two key genes involved in cysteine and glutathione biosynthesis (encoding adenosine 5'-phosphosulfate reductase and γ-glutamylcysteine synthetase, respectively) were upregulated within the first day after TMV inoculation under +S conditions. Sulfate withdrawal from the soil was accelerated at the beginning of the infection, whereas it declined in the long term, leading to an accumulation of sulfur in the soil of plants grown with sulfate. This observation could be correlated with a decrease in sulfur contents in TMV-infected leaves in the long term. In summary, this is the first study that demonstrates a link between the activation of cysteine and glutathione metabolism and the induction of SIR/SED during a compatible plant-virus interaction in tobacco plants, indicating a general mechanism behind SIR/SED.

High resistance to Sclerotinia sclerotiorum in transgenic soybean plants transformed to express an oxalate decarboxylase gene

Pathogenesis of Sclerotinia sclerotiorum (white mould) has been associated with fungal secretion of oxalic acid (OA). Enzymes capable of degrading OA have been utilized to produce transgenic resistant plants. Transgenic soybean lines containing the decarboxylase gene (oxdc) isolated from a Flammulina sp. were produced by the biolistic process. Molecular analysis revealed successful incorporation of the gene into the plant genome and showed that the oxdc gene was transferred to the progeny plants. Sixteen T2 transgenic events were screened for S. sclerotiorum resistance using a detached leaf assay. The white mould disease progress curve displayed a significant delay in symptom development in all oxdc events compared with the nontransgenic genotype. Area under the disease progress curve (audpc) showed reduction in severity ranging from 61% to 96% comparing the oxdc events with the nontransgenic control. One event (OXDC.9.21) presented some plants that did not show any symptoms after 92 h. RT‐PCR analysis for detection of oxdc gene transcripts suggested that expression of the oxdc gene is associated with resistance to S. sclerotiorum.

Tobacco Mosaic Virus Infection Results in an Increase in Recombination Frequency and Resistance to Viral, Bacterial, and Fungal Pathogens in the Progeny of Infected Tobacco Plants

Our previous experiments showed that infection of tobacco (Nicotiana tabacum) plants with Tobacco mosaic virus (TMV) leads to an increase in homologous recombination frequency (HRF). The progeny of infected plants also had an increased rate of rearrangements in resistance gene-like loci. Here, we report that tobacco plants infected with TMV exhibited an increase in HRF in two consecutive generations. Analysis of global genome methylation showed the hypermethylated genome in both generations of plants, whereas analysis of methylation via 5-methyl cytosine antibodies demonstrated both hypomethylation and hypermethylation. Analysis of the response of the progeny of infected plants to TMV, Pseudomonas syringae, or Phytophthora nicotianae revealed a significant delay in symptom development. Infection of these plants with TMV or P. syringae showed higher levels of induction of PATHOGENESIS-RELATED GENE1 gene expression and higher levels of callose deposition. Our experiments suggest that viral infection triggers specific changes in progeny that promote higher levels of HRF at the transgene and higher resistance to stress as compared with the progeny of unstressed plants. However, data reported in these studies do not establish evidence of a link between recombination frequency and stress resistance.

Activity of benzothiadiazole on chrysanthemum yellows phytoplasma (‘ Candidatus Phytoplasma asteris’) infection in daisy plants

A commercial preparation of the plant resistance elicitor benzothiadiazole (BTH) (Bion, Syngenta Crop Protection) was tested for its capacity to induce systemic resistance against chrysanthemum yellow phytoplasma (CYP) infection in the Chrysanthemum carinatum plant. Following one 2.4 mM BTH application, plants were exposed to CYP-infective Macrosteles quadripunctulatus leafhoppers. Symptom development and phytoplasma multiplication in the test plants were measured over time. BTH application delayed symptom development and phytoplasma multiplication in treated plants compared with the control ones. CYP titre and symptom severity were significantly lower for the first two weeks post-inoculation in treated plants compared with the control ones, suggesting that systemic acquired resistance (SAR) induced by BTH in C. carinatum is temporary. Higher concentrations of BTH resulted in phytotoxic effects involving the whitening of apical leaves. BTH application was ineffective in reducing the transmission efficiency of CYP by its leafhopper vector. Actually, in both single and group transmission tests, the proportion of infected plants was similar among BTH-treated and untreated plants. The survival of M. quadripunctulatus was unaffected by feeding on BTH-treated daisy plants. Moreover, when leafhoppers were allowed to choose between treated and untreated plants, they showed no preference. We conclude that SAR induced in daisy plants by BTH has no detrimental effects on the vector leafhopper. If the activity of BTH against phytoplasmas is confirmed also on other phytoplasma/host–plant associations, BTH applications might be included in new, more environmentally friendly, integrated management strategies of phytoplasmoses.