Selection of cocoa clones for resistance to Phytophthora palmivora by artificial inoculation and natural infection in the field

2021 ◽  
Author(s):  
Vanusa Rodrigues de Souza ◽  
Edna Dora Martins Newman Luz ◽  
José Luis Pires ◽  
Marcos Vinicius Oliveira dos Santos ◽  
Elisângela dos Santos ◽  
...  
Keyword(s):  
Natural Infection ◽  
Artificial Inoculation ◽  
Phytophthora Palmivora ◽  
Selection Of

scholarly journals Selection of Conserved Epitopes from Hepatitis C Virus for Pan-Populational Stimulation of T-Cell Responses

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Magdalena Molero-Abraham ◽  
Esther M. Lafuente ◽  
Darren R. Flower ◽  
Pedro A. Reche
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
T Cell ◽  
Natural Infection ◽  
Effective Means ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
T Cell Response ◽  
Cell Responses ◽  
Selection Of

The hepatitis C virus (HCV) is able to persist as a chronic infection, which can lead to cirrhosis and liver cancer. There is evidence that clearance of HCV is linked to strong responses by CD8 cytotoxic T lymphocytes (CTLs), suggesting that eliciting CTL responses against HCV through an epitope-based vaccine could prove an effective means of immunization. However, HCV genomic plasticity as well as the polymorphisms of HLA I molecules restricting CD8 T-cell responses challenges the selection of epitopes for a widely protective vaccine. Here, we devised an approach to overcome these limitations. From available databases, we first collected a set of 245 HCV-specific CD8 T-cell epitopes, all known to be targeted in the course of a natural infection in humans. After a sequence variability analysis, we next identified 17 highly invariant epitopes. Subsequently, we predicted the epitope HLA I binding profiles that determine their potential presentation and recognition. Finally, using the relevant HLA I-genetic frequencies, we identified various epitope subsets encompassing 6 conserved HCV-specific CTL epitopes each predicted to elicit an effective T-cell response in any individual regardless of their HLA I background. We implemented this epitope selection approach for free public use at the EPISOPT web server.

scholarly journals Response of Barley Genotypes to Fusarium Head Blight under Natural Infection and Artificial Inoculation Conditions

2021 ◽  
Vol 37 (5) ◽  
pp. 455-464
Author(s):  
Raja Khanal ◽  
Thin Meiw Choo ◽  
Allen G. Xue ◽  
Bernard Vigier ◽  
Marc E. Savard ◽  
...  
Keyword(s):  
Fusarium Head Blight ◽  
Prince Edward Island ◽  
Natural Infection ◽  
Spring Barley ◽  
Artificial Inoculation ◽  
High Yield ◽  
Conidial Suspension ◽  
Head Blight ◽  
One Year ◽  
Barley Genotypes

Forty-eight spring barley genotypes were evaluated for deoxynivalenol (DON) concentration under natural infection across 5 years at Harrington, Prince Edward Island. These genotypes were also evaluated for Fusarium head blight (FHB) severity and DON concentration under field nurseries with artificial inoculation of <i>Fusarium graminearum</i> by the grain spawn method across 2 years at Ottawa, Ontario, and one year at Hangzhou, China. Additionally, these genotypes were also evaluated for FHB severity under greenhouse conditions with artificial inoculation of <i>F. graminearum</i> by conidial suspension spray method across 3 years at Ottawa, Ontario. The objective of the study was to investigate if reactions of barley genotypes to artificial FHB inoculation correlate with reactions to natural FHB infection. DON concentration under natural infection was positively correlated with DON concentration (<i>r</i> = 0.47, <i>P</i> < 0.01) and FHB incidence (<i>r</i> = 0.56, <i>P</i> < 0.01) in the artificially inoculated nursery with grain spawn method. Therefore, the grain spawn method can be used to effectively screen for low DON. FHB severity, generated from greenhouse spray, however, was not correlated with DON concentration (<i>r</i> = 0.12, <i>P</i> > 0.05) under natural infection and it was not correlated with DON concentration (<i>r</i> = -0.23, <i>P</i> > 0.05) and FHB incidence (<i>r</i> = 0.19, <i>P</i> > 0.05) in the artificially inoculated nursery with grain spawn method. FHB severity, DON concentration, and yield were affected by year, genotype, and the genotype × year interaction. The effectiveness of greenhouse spray inoculation for indirect selection for low DON concentration requires further studies. Nine of the 48 genotypes were found to contain low DON under natural infection. Island barley had low DON and also had high yield.

Correlation between maize genotypes and the stalk rot caused by maize Fusarium

2007 ◽  
Vol 55 (4) ◽  
pp. 447-452 ◽  
Author(s):  
C. Szőke ◽  
T. Árendás ◽  
F. Rácz ◽  
J. Pintér ◽  
E. Nagy ◽  
...  
Keyword(s):  
Natural Infection ◽  
Female Parent ◽  
Weather Conditions ◽  
Artificial Inoculation ◽  
Resistance Level ◽  
Stalk Rot ◽  
Maize Genotypes ◽  
Female Component ◽  
Different Levels ◽  
Single Cross Hybrids

Six single-cross hybrids and their parental lines were inoculated with the FG36 Fusarium graminearum isolate in 2005 and 2006. In both years the degree of infection increased after artificial inoculation for both the hybrids and the inbred lines compared with the level of natural infection. The more severe stalk infection recorded in 2005 than in 2006 could be attributed to the weather conditions during flowering and harvesting.The 18 genotypes examined exhibited different levels of resistance to fusarium stalk rot. It could be concluded from the results that the resistance level of the female parent was decisive in the inheritance of the response to fusarium stalk rot (female component-hybrid r = 0.88, male component-hybrid r = 0.39).Some genotypes may be severely affected in epidemic years, while exhibiting a lower rate of infection in years with lower pathogen pressure. This suggests that successful breeding for resistance can only be carried out efficiently by means of artificial inoculation.

Genetic mapping of resistance factors to Phytophthora palmivora in cocoa

Genome ◽  
2001 ◽  
Vol 44 (1) ◽  
pp. 79-85 ◽  
Author(s):  
M -H Flament ◽  
I Kebe ◽  
D Clément ◽  
I Pieretti ◽  
A -M Risterucci ◽  
...  
Keyword(s):  
Quantitative Trait ◽  
Natural Infection ◽  
Genetic Maps ◽  
Aflp Markers ◽  
Phytophthora Palmivora ◽  
Good Prediction ◽  
Linkage Groups ◽  
Genetic Determination ◽  
Total Length ◽  
Adult Trees

Phytophthora palmivora causes pod rot, a serious disease on cocoa widespread throughout the producing regions. In order to ascertain the genetic determination of cocoa resistance to P. palmivora, a study was carried out on two progenies derived from crosses between a heterozygous, moderately resistant Forastero clone, T60/887, and two closely related and highly susceptible Forastero clones, one completely homozygous, IFC2, and one partially heterozygous, IFC5. The cumulative size of both progenies was 112 individuals. Plants were subjected to natural and artificial inoculation of P. palmivora in Côte d'Ivoire. The genetic maps of T60/887 and of IFC5 were constructed using amplified fragment length polymorphism (AFLP) markers and microsatellites. The map of T60/887 comprised 198 markers assembled in 11 linkage groups and representing a total length of 793 cM. The map of IFC5 comprised 55 AFLP markers that were assembled into six linkage groups for a total length of 244 cM. Ratio of rotten over total number of fruit under natural infection was measured for each tree over two harvests. Artificial inoculations were performed on leaves and pods. These tests were weakly correlated with the pod rot rate in the field. Five quantitative trait loci (QTLs) of resistance were detected for T60/887 but none were common between the three traits measured. Stability and reliability of the experimental procedures are discussed and revealed the difficult use of these artificial tests on adult trees for a good prediction of field resistance.Key words: Theobroma cacao, Phytophthora palmivora, cocoa black pod disease, genetic map, quantitative trait locus (QTL).

scholarly journals Variation Within and Among Vitis spp. for Foliar Resistance to the Powdery Mildew Pathogen Erysiphe necator

Plant Disease ◽  
2011 ◽  
Vol 95 (2) ◽  
pp. 202-211 ◽  
Author(s):  
Lance Cadle-Davidson ◽  
David R. Chicoine ◽  
Nancy H. Consolie
Keyword(s):  
Powdery Mildew ◽  
Control Strategies ◽  
Natural Infection ◽  
Durable Resistance ◽  
Erysiphe Necator ◽  
Detached Leaves ◽  
Cold Hardy ◽  
Powdery Mildew Pathogen ◽  
Vitis Spp ◽  
Selection Of

To complement existing control strategies, grape growers desire cultivars with resistance to powdery mildew caused by Erysiphe necator. Numerous disease resistance screens of diverse Vitis germplasm have been conducted previously to identify powdery mildew resistance but ratings of named cultivars were inconsistent and identities of resistant individuals in wild species were not typically provided. In the current study, controlled inoculations of a single isolate were made onto detached leaves from 1,025 Vitis accessions. The results were compared with natural epidemics in two vineyards: the cold-hardy Vitis spp. repository in Geneva, NY, in 2007–08, and a replicated vineyard of 89 Vitis accessions in Fredonia, NY in 2006–08. Of the genotypes screened using both natural infection and single-isolate inoculation, 33% were resistant to a single isolate but susceptible to diverse isolates in either or both vineyards, possibly due to race-specific resistance. This was exemplified by selection of E. necator genotypes virulent to Vitis labrusca in the Fredonia, NY vineyard, which is surrounded by production of the interspecific labrusca hybrids Concord and Niagara. Otherwise, there was good correlation of ratings between the vineyard and single-isolate ratings (r = 0.55 to 0.56) and between Geneva and Fredonia vineyard ratings (r = 0.75). No accession rated in all three screens was immune from infection. Although individual accessions of V. aestivalis, V. palmata, Vitis × doaniana, and Ampelopsis brevipedunculata were resistant in Geneva and Fredonia, each well-represented species had notable intraspecific variation in resistance. For 129 interspecific hybrids in this and previous studies, ratings infrequently corresponded among previous studies (39%) and between the current and previous studies (17 to 46%). However, three cultivars (Cayuga White, Diana, and Mars) were consistently rated as resistant across four independent studies. The results underscore the importance of uniform testing in multiple environments and the need for strategies for the development of cultivars with durable resistance.

scholarly journals Mapping and validation of the genes for resistance to Pyrenophora teres f. teres in barley (Hordeum vulgare L.)

2003 ◽  
Vol 54 (12) ◽  
pp. 1369 ◽  
Author(s):  
M. Cakir ◽  
S. Gupta ◽  
G. J. Platz ◽  
G. A. Ablett ◽  
R. Loughman ◽  
...  
Keyword(s):  
Natural Infection ◽  
Adult Plant ◽  
Research Station ◽  
Pyrenophora Teres ◽  
Net Blotch ◽  
Hordeum Vulgare L ◽  
Breeding Programs ◽  
Barley Breeding ◽  
Software Packages ◽  
Selection Of

Identification and deployment of disease resistance genes are key objectives of Australian barley breeding programs. Two doubled haploid (DH) populations derived from Tallon × Kaputar (TK) and VB9524 × ND11231 (VN) crosses were used to identify markers for net type net blotch (NTNB) (Pyrenophora teres f. teres). The maps included 263 and 250 markers for TK and VN populations, respectively. The TK population was screened with 5 pathotypes and the VN population with 1 pathotype of NTNB as seedlings in the glasshouse. In addition, the TK population was subjected to natural infection in the field at Hermitage Research Station, Qld. Analyses of the markers were performed using the software packages MapManager and Qgene. One region on chromosome 6H was strongly associated with resistance to NTNB in both populations (R2 = 83% for TK and 66% for VN). In the TK population, 2 more quantitative trait loci (QTLs) were identified on chromosomes 2H and 3H, with R2 values of 30% and 31%, respectively. These associations were consistent over all pathotypes studied during the seedling stage. The same QTL on chromosome 6H was also found to be highly significantly associated (R2 = 65%) with the adult plant (field) response in the TK population. There are several very closely linked markers showing strong associations in these regions. Association of the 4 markers on chromosome 6H QTL with resistance to the NTNB has been validated in 2 other DH populations derived from barley crosses Pompadour × Stirling and WPG8412 × Stirling. These markers present an opportunity for marker assisted selection of lines resistant to NTNB in barley breeding programs.

scholarly journals Evaluation of Maize Inbred Lines for Resistance to Fusarium Ear Rot and Fumonisin Accumulation in Grain in Tropical Africa

Plant Disease ◽  
2007 ◽  
Vol 91 (3) ◽  
pp. 279-286 ◽  
Author(s):  
C. G. Afolabi ◽  
P. S. Ojiambo ◽  
E. J. A. Ekpo ◽  
A. Menkir ◽  
R. Bandyopadhyay
Keyword(s):  
Disease Severity ◽  
Natural Infection ◽  
Fusarium Verticillioides ◽  
Field Trials ◽  
Inbred Lines ◽  
Artificial Inoculation ◽  
Fusarium Ear Rot ◽  
Ear Rot ◽  
Maize Inbred Lines ◽  
Resistant Lines

Fusarium ear rot and fumonisin contamination is a major problem facing maize growers worldwide, and host resistance is the most effective strategy to control the disease, but resistant genotypes have not been identified. In 2003, a total of 103 maize inbred lines were evaluated for Fusarium ear rot caused by Fusarium verticillioides in field trials in Ikenne and Ibadan, Nigeria. Disease was initiated from natural infection in the Ikenne trial and from artificial inoculation in the Ibadan trial. Ear rot severity ranged from 1.0 to 6.0 in both locations in 2003. Fifty-two inbred lines with disease severity ≤3 (i.e., ≤ 10% visible symptoms on ears) were selected and reevaluated in 2004 for ear rot resistance, incidence of discolored kernels, and fumonisin contamination in grain. At both locations, ear rot severity on the selected lines was significantly (P < 0.0020) higher in 2004 than in 2003. The effects of selected inbred lines on disease severity were highly significant at Ikenne (P = 0.0072) and Ibadan (P < 0.0001) in 2004. Inbred lines did not affect incidence of discolored kernels at both locations and across years except at Ikenne (P = 0.0002) in 2004. Similarly, significant effects of inbred lines on fumonisin concentration were observed only at Ikenne (P = 0.0201) in 2004. However, inbred lines 02C14585, 02C14593, 02C14603, 02C14606, 02C14624, and 02C14683 had consistently low disease severity across years and locations. Fumonisin concentration was significantly correlated with ear rot only at Ikenne (R = 0.42, P < 0.0001). Correlation between fumonisin concentration and incidence of discolored kernels was also significant at Ikenne (R = 0.39, P < 0.0001) and Ibadan (R = 0.35, P = 0.0007). At both locations, no significant inbred × year interaction was observed for fumonisin concentration. Five inbred lines, namely 02C14585, 02C14603, 02C14606, 02C14624, and 02C14683, consistently had the lowest fumonisin concentration in both trials. Two of these inbred lines, 02C14624 and 02C14585, had fumonisin levels <5.0 μg/g across years in trials where disease was initiated from both natural infection and artificial inoculation. These lines that had consistently low disease severity are useful for breeding programs to develop fumonisin resistant lines.

scholarly journals Screening of anti-mycobacterial compounds in a naturally infected zebrafish embryo model

2016 ◽  
Author(s):  
James P Dalton ◽  
Benedict Uy ◽  
Kazuhide Okuda ◽  
Christopher J Hall ◽  
William A Denny ◽  
...  
Keyword(s):  
Zebrafish Embryo ◽  
Natural Infection ◽  
Rapid Screening ◽  
Infection Model ◽  
Zebrafish Embryos ◽  
Drug Trials ◽  
Bioluminescent Signal ◽  
High Level ◽  
Selection Of

Mycobacterium tuberculosisis a deadly human pathogen that latently infects a third of the worlds population, resulting in approximately 1.5 million deaths per year. Due to the difficulties and expense of carrying out animal drug trials using M. tuberculosis and rodents, infections of the zebrafishDanio reriowithM. marinumhave been used as a surrogate. However the methods so far described require specialised equipment and a high level of operator expertise. We investigated a natural infection model where zebrafish embryos are infected through incubation in media containingM. marinum. Using bioluminescently labelledM. marinum, we have characterised the nature of infection and established a model for interventional drug therapy. We have used a selection of traditional and experimental compounds to validate this model for anti-mycobacterial drug discovery. We observed that only three of the six treatments tested (Delamonid, SN30527 and rifampicin) retarded the growth ofM. marinumin vitro. In contrast, five of the six treatments (Pretomanid, Delamanid, SN30488, SN30527 and rifampicin) retarded the growth ofM. tuberculosisin vitro. Importantly, these same five treatments significantly reduced the bioluminescent signal from naturally infected zebrafish embryos. Overall this study has demonstrated that zebrafish embryos naturally infected with bioluminescentM. marinumM can be used for the rapid screening of anti-mycobacterial compounds with readily available equipment and limited expertise. The result is an assay that can be carried out by a wide variety of laboratories for minimal cost and without high levels of zebrafish expertise.

scholarly journals Mono-Locus and Pyramided Resistant Grapevine Cultivars Reveal Early Putative Biomarkers Upon Artificial Inoculation With Plasmopara viticola

2021 ◽  
Vol 12 ◽  
Author(s):  
Ramona Mihaela Ciubotaru ◽  
Pietro Franceschi ◽  
Luca Zulini ◽  
Marco Stefanini ◽  
Domen Škrab ◽  
...  
Keyword(s):  
Plasmopara Viticola ◽  
Pinot Noir ◽  
Artificial Inoculation ◽  
Sources Of Resistance ◽  
Volatile Organic ◽  
Primary Compounds ◽  
Plant Metabolite ◽  
Different Sources ◽  
Resistant Genotypes ◽  
Selection Of

One of the most economically important grapevine diseases is Downy mildew (DM) caused by the oomycete Plasmopara viticola. A strategy to reduce the use of fungicides to compensate for the high susceptibility of V. vinifera is the selection of grapevine varieties showing pathogen-specific resistance. We applied a metabolomics approach to evaluate the metabolic modulation in mono-locus resistant genotypes carrying one locus associated with P. viticola resistance (Rpv) (BC4- Rpv1, Bianca- Rpv3-1, F12P160- Rpv12, Solaris- Rpv10), as well as in pyramided resistant genotypes carrying more than one Rpv (F12P60- Rpv3-1; Rpv12 and F12P127- Rpv3-1, Rpv3-3; Rpv10) taking as a reference the susceptible genotype Pinot Noir. In order to understand if different sources of resistance are associated with different degrees of resistance and, implicitly, with different responses to the pathogen, we considered the most important classes of plant metabolite primary compounds, lipids, phenols and volatile organic compounds at 0, 12, 48, and 96 h post-artificial inoculation (hpi). We identified 264 modulated compounds; among these, 22 metabolites were found accumulated in significant quantities in the resistant cultivars compared to Pinot Noir. In mono-locus genotypes, the highest modulation of the metabolites was noticed at 48 and 96 hpi, except for Solaris, that showed a behavior similar to the pyramided genotypes in which the changes started to occur as early as 12 hpi. Bianca, Solaris and F12P60 showed the highest number of interesting compounds accumulated after the artificial infection and with a putative effect against the pathogen. In contrast, Pinot Noir showed a less effective defense response in containing DM growth.

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