Relationships between free carbohydrate levels and resistance or susceptibility of Capsicum annuum to Phytophthora capsici

1984 ◽  
Vol 62 (5) ◽  
pp. 1036-1043 ◽  
Author(s):  
Michel Bounias ◽  
Claude Coulomb ◽  
Philippe J. Coulomb
Keyword(s):  
Molecular Mechanisms ◽  
Phytophthora Capsici ◽  
Susceptible Variety ◽  
Resistant Variety ◽  
Resistant Varieties ◽  
Resistant Strains ◽  
Resistance To Infection ◽  
Cellular Pathways ◽  
Carbohydrate Levels ◽  
Free Carbohydrates

The chromatographic analysis of the free carbohydrate content of leaves and stems of pepper showed 19 major fractions which were gathered in 8 structural classes. A number of correlations were found between the respective carbohydrate levels of two varieties of pepper, one susceptible and the other resistant to downy mildew, and also between those of healthy and inoculated tissues. Some cases of departures from the established correlations were observed and discussed with respect to their hypothetical involvement in the character of resistance and susceptibility to the infection. The concentrations of free carbohydrates of the dideoxyhexose group are increased in inoculated leaves of both susceptible and resistant varieties and those of the rhamnose group are depressed in inoculated leaves of the sole susceptible variety. Sucrose strongly increases in inoculated stems but decreases in the inoculated leaves of the sole resistant variety; concomitantly glucose and fructose also increase in inoculated stems, whereas they decrease in inoculated leaves of both susceptible and resistant strains. The results suggest a number of hypotheses concerning the molecular mechanisms of the host resistance to infection in relation to the cellular pathways of sugar translocation.

Transcriptome analysis of scions grafted to potato rootstock for improving late blight resistance

2020 ◽  
Author(s):  
Yuexin Li ◽  
Degang Zhao
Keyword(s):  
Disease Resistance ◽  
Late Blight ◽  
Protein Kinases ◽  
Molecular Mechanisms ◽  
Late Blight Resistance ◽  
Potato Late Blight ◽  
Susceptible Variety ◽  
Resistant Variety ◽  
Blight Resistance ◽  
Expression Levels

Abstract Background: Late blight seriously threatens potato cultivation worldwide. The severe and widespread damage caused by the fungal pathogen can lead to drastic decreases in potato yield. Although grafting technology has been widely used to improve crop resistance, the effects of grafting on potato late blight resistance as well as the associated molecular mechanisms remain unclear. Therefore, we performed RNA transcriptome sequencing analysis and the late blight resistance testing of the scion when the potato late blight-resistant variety Qingshu 9 and the susceptible variety Favorita were used as the rootstock and scion, respectively, and vice versa. The objective of this study was to evaluate the influence of the rootstock on scion disease resistance and to clarify the related molecular mechanisms.Results: A Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis revealed that the expression levels of genes related to plant–pathogen interactions, plant mitogen-activated protein kinase (MAPK) signaling pathways, and plant hormone signal transduction pathways were significantly up-regulated in the scion when Qingshu 9 was used as the rootstock. These genes included late blight response genes encoding calcium-dependent protein kinases (CDPKs), chitin elicitor receptor kinases (CERKs), LRR receptor serine/threonine protein kinases (LRR-LRKs), NPR family proteins in the salicylic acid synthesis pathway, and MAPKs. When Favorita was used as the rootstock, the expression levels of the late blight response genes were not up-regulated in the Qingshu 9 scion, but the expression levels of the genes related to proline metabolism, fatty acid chain elongation, and diterpenoid biosynthesis pathways were down-regulated. Resistance results showed that self-grafting of the susceptible variety and grafting with the resistant variety as the rootstock increased the resistance of the susceptible scion to late blight. However, the resistance was stronger after grafting with the resistant variety as the rootstock. Using the susceptible variety as the rootstock decreased the late blight resistance of the resistant scion.Conclusions: Our results showed that changes to the expression of disease resistance genes in the scion after grafting are associated with late blight resistance. The results provide the basis for exploring the molecular mechanism underlying the effects of rootstocks on scion disease resistance.

scholarly journals Transcriptome analysis of resistant and susceptible pepper (Capsicum annuum L.) in response to Xanthomonas campestris pv. Vesicatoria

2020 ◽  
Author(s):  
Shenghua Gao ◽  
Fei Wang ◽  
Juntawong Niran ◽  
Ning Li ◽  
Yanxu Yin ◽  
...  
Keyword(s):  
Transcriptome Analysis ◽  
Xanthomonas Campestris ◽  
Molecular Mechanisms ◽  
Sugar Metabolism ◽  
Amino Sugar ◽  
Mapk Signaling ◽  
Susceptible Variety ◽  
Differentially Expressed ◽  
Resistant Variety ◽  
Sequencing Platform

AbstractBacterial spot (BS) disease of pepper, incited by Xanthomonas campestris pv. Vesicatoria (Xcv), is one of the most serious diseases. For a comparative analysis of defense response to Xcv infection, we performed a transcriptome analysis of BS -susceptible cultivar ECW and -resistant cultivar VI037601 using the HiSeq™ 2500 sequencing platform. Approximately 140.15 G clean data were generated from eighteen libraries. From the libraries generated, we identified 52,041 genes including 35,336 reference genes, 16,705 novel transcripts, and 4,794 differentially expressed genes (DEGs). There were 1,291, 2,956, 1,795 and 2,448 DEGs in ECW-24h-vs-ECW-0h, ECW-48h-vs-ECW-0h, VI037601-24h-vs-VI037601-0h and VI037601-48h-vs-VI037601-0h groups, respectively. Interestingly, DEGs involved in disease response in the resistant variety were induced at an earlier stage and at higher levels compared with the susceptible variety. Key enriched categories included amino sugar and nucleotide sugar metabolism, sesquiterpenoid and triterpenoid biosynthesis and MAPK signaling pathway. Moreover, 273 DEGs only differentially expressed in VI037601 and 436 overlapping DEGs in ECW and VI037601 post Xcv inoculation, including NBS-LRR genes, oxidoreductase gene, WRKY and NAC transcription factors were identified, which were mainly involved in metabolic process, response to stimulus and biological regulation pathways. Quantitative RT-PCR of sixteen selected DEGs further validated the RNA-seq differential gene expression analysis. Our results will provide a valuable resource for understanding the molecular mechanisms of pepper resistance to Xcv infection and improving pepper resistance cultivars against Xcv.

scholarly journals Reducing Pesticide Costs Using Tungro Resistant Varieties

2003 ◽  
Vol 3 (1) ◽  
pp. 28-39
Author(s):  
Aniceto Villar ◽  
◽  
Lorenza de Pedro
Keyword(s):  
Rice Variety ◽  
Susceptible Variety ◽  
Dry Season ◽  
Resistant Variety ◽  
Poor Growth ◽  
Resistant Varieties ◽  
Rice Tungro Disease ◽  
Net Profit

Insecticide-sprayed and unsprayed IR64, rice variety susceptible to tungro virus had very poor growth and very low yield compared to the intermediate and resistant varieties. As a result, higher net profit was observed on PSB Rc18 (resistant variety) during the dry season, while a negative profit per cropping was obtained on the sprayed and unsprayed susceptible variety. The study implied that cypermethrin is not effective in controlling rice tungro disease, thus the use of resistant varieties is more effective and profitable.

Aphids do not avoid resistance in Australian lupin (Lupinus angustifolius, L. luteus) varieties

2003 ◽  
Vol 93 (5) ◽  
pp. 403-411 ◽  
Author(s):  
O.R. Edwards ◽  
T.J. Ridsdill-Smith ◽  
F.A. Berlandier
Keyword(s):  
Field Trials ◽  
Resistance Mechanisms ◽  
Aphid Species ◽  
Susceptible Variety ◽  
Lupinus Angustifolius ◽  
Resistant Variety ◽  
Growth And Survival ◽  
Resistant Varieties ◽  
Late Instar ◽  
Selection Of

AbstractLaboratory bioassays and field trials were used to characterize resistance to three aphid species (Myzus persicae (Sulzer), Acyrthosiphon kondoi Shinji, Aphis craccivora (Koch) in two aphid-resistant varieties (Kalya, Tanjil) and one susceptible variety (Tallerack) of Lupinus angustifolius L., and in one resistant variety (Teo) and one susceptible variety (Wodjil) of L. luteus L. Host selection tests in the glasshouse showed that alates of all three species preferred L. luteus to L. angustifolius, but provided no evidence that alates selected susceptible varieties over resistant. These results were supported by a field trial, which showed no difference in the number of colonizing A. kondoi alates collected from the resistant and susceptible lines of each lupin species, but there were significantly more late-instar nymphs and apterous adults on the susceptible lines. In laboratory host suitability experiments, there was much greater suppression of aphid growth and survival on Teo than on Kalya and Tanjil. In field trials, the numbers of aphids were generally lower on resistant compared to susceptible lines of both lupin species with one notable exception: M. persicae numbers were not lower on the resistant variety Tanjil compared to the susceptible variety Tallerack (L. angustifolius). These results suggest that the resistance mechanisms in both lupin species do not affect the selection of hosts by colonizing aphids, but rather are affecting the growth, survival and possibly reproduction of aphids after settling.

Transcriptome Analysis of Grafted Potato Rootstock for Improvement of Scion Late-Blight Resistance

2020 ◽  
Author(s):  
Yuexin Li ◽  
Degang Zhao
Keyword(s):  
Late Blight ◽  
Molecular Mechanisms ◽  
Enrichment Analysis ◽  
Late Blight Resistance ◽  
Potato Late Blight ◽  
Mapk Signaling ◽  
Susceptible Variety ◽  
Resistant Variety ◽  
Blight Resistance

Abstract Late blight seriously threatens potato cultivation worldwide. Damage caused by the fungus, which is severe and widespread, can lead to drastic reductions in potato yield and even total loss. Although grafting technology has been widely used to improve crop resistance, the effects and associated molecular mechanisms of grafting on resistance to potato late blight are unclear. In this study, we therefore performed RNA transcriptome sequencing of the scion when potato late blight-resistant variety Qingshu 9 and susceptible variety Favorita were used as the rootstock and scion, respectively, and vice versa. Using the sequencing results, we analyzed the influence of the rootstock on scion resistance and related molecular mechanisms. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis revealed that plant–pathogen interactions, the plant MAPK signaling pathway, and genes on the SA pathway were significantly up-regulated in the scion when Qingshu 9 was used as the rootstock. When Favorita was used as the rootstock, β-ketoacyl-CoA synthase-related genes in the scion, Qingshu 9, were significantly down-regulated. Resistance to late blight on scion leaves were also tested in vitro, which results consistent with those obtained by sequencing. All the generated evidence indicates that the use of resistant and susceptible varieties as rootstocks can respectively increase and reduce resistance to late blight. Our sequencing results further elucidate the molecular mechanism underlying the post-grafting effects of rootstocks on late blight resistance and provide a theoretical basis for the transfer of resistance genes between scions and rootstocks after grafting.

scholarly journals Transcriptome analysis of scions grafted to potato rootstock for improving late blight resistance

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Yuexin Li ◽  
Degang Zhao
Keyword(s):  
Disease Resistance ◽  
Late Blight ◽  
Protein Kinases ◽  
Molecular Mechanisms ◽  
Late Blight Resistance ◽  
Potato Late Blight ◽  
Lesion Size ◽  
Susceptible Variety ◽  
Resistant Variety ◽  
Blight Resistance

Abstract Background Late blight seriously threatens potato cultivation worldwide. The severe and widespread damage caused by the fungal pathogen can lead to drastic decreases in potato yield. Although grafting technology has been widely used to improve crop resistance, the effects of grafting on potato late blight resistance as well as the associated molecular mechanisms remain unclear. Therefore, we performed RNA transcriptome sequencing analysis and the late blight resistance testing of the scion when the potato late blight-resistant variety Qingshu 9 and the susceptible variety Favorita were used as the rootstock and scion, respectively, and vice versa. The objective of this study was to evaluate the influence of the rootstock on scion disease resistance and to clarify the related molecular mechanisms. Results A Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis revealed that the expression levels of genes related to plant–pathogen interactions, plant mitogen-activated protein kinase (MAPK) signaling pathways, and plant hormone signal transduction pathways were significantly up-regulated in the scion when Qingshu 9 was used as the rootstock. Some of these genes encoded calcium-dependent protein kinases (CDPKs), chitin elicitor receptor kinases (CERKs), LRR receptor serine/threonine protein kinases (LRR-LRKs), NPR family proteins in the salicylic acid synthesis pathway, and MAPKs which were potato late blight response proteins. When Favorita was used as the rootstock, only a few genes of late blight response genes were upregulated in the scion of Qingshu 9. Grafted plants using resistant variety as rootstocks inoculated with P. infestans spores showed significant reductions in lesion size while no significant difference in lesion size was observed when susceptible variety was used as the rootstock. We also showed that this induction of disease resistance in scions, especially scions derived from susceptible potato varieties was mediated by the up-regulation of expression of genes involved in plant disease resistance in scions. Conclusions Our results showed that potato grafting using late blight resistant varieties as rootstocks could render or enhance resistance to late blight in scions derived from susceptible varieties via up-regulating the expression of disease resistant genes in scions. The results provide the basis for exploring the molecular mechanism underlying the effects of rootstocks on scion disease resistance.

scholarly journals 1456. Resistance Mechanisms of Tigecycline in Enterococcus faecalis

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S730-S731
Author(s):  
Bing Bai ◽  
Zewen Wen ◽  
Zhiwei Lin ◽  
Tam Vincent H ◽  
Zhijian Yu
Keyword(s):  
Enterococcus Faecalis ◽  
Molecular Mechanisms ◽  
Genetic Mutations ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Whole Genome ◽  
Synonymous Mutations ◽  
Target Sites ◽  
Parental Isolate ◽  
Resistant Strains

Abstract Background Enterococcus faecalis have been regarded as one of the leading causes of the nosocomial infections worldwide. Tigecycline (TGC) is considered as a choice of last resort for the treatment of infections caused by multidrug-resistant E. faecalis, however, the emergence of TGC non-susceptibility has posted the therapeutic challenge. Non-susceptibility in clinical strains could be due to resistance (MIC >0.5 mg/l) or heteroresistance. Therefore, this study aimed to understand the underlying molecular mechanisms of TGC resistance and heteroresistance in E. faecalis. Methods In vitro induction experiments were carried out under TGC pressure with two TGC- sensitive E. faecalis strains. Heteroresistance was evaluated by population analysis profiling (PAP) in 270 clinical TGC- sensitive E. faecalis strains. TGC susceptibility was determined by the agar dilution method. Resistance and heteroresistance mechanisms were investigated by identifying genetic mutations in tetracycline (Tet) target sites and susceptibility testing in the presence of the efflux protein inhibitors phenylalanine-arginine-β-naphthylamide (PaβN) and carbonyl cyanide m chlorophenylhydrazine (CCCP). Comparison of single nucleotide polymorphism in the whole genome between the parental isolate and two TGC-resistant strains were investigated by next-generation sequencing. Results No mutations in Tet target sites in seven TGC heteroresistant strains were present, whereas the mutations in Tet target sites of seven TGC-resistant E. faecalis were frequently found (Table 1). TGC MICs in heteroresistant strains were reduced by CCCP (Table 2). Whole genome sequencing revealed the same non-synonymous mutations and transcoding deletions in the exons of several genes encoding for various enzymes or transfer systems (Table 3). Table 1. The characteristics of the antimicrobial susceptibility, resistance mechanism of TGC-induced resistant isolates Table 2. Characteristics of clinical heteroresistant mother E. faecalis strains and heteroresistance-derived E. faecalis clones Table 3. List of mutation-related genes, amino acids and proteins by comparison of whole genome between the parental isolate and the TGC-induced resistant strains Conclusion Our data indicated that the main mechanism of TGC heteroresistance in E. faecalis might be associated with the efflux pumps. TGC resistance in E. faecalis was associated with mutations in the 16SrRNA site or 30S ribosome protein S10. The genetic mutations in several enzymes and transfer systems might also participate in the resistance development to TGC in E. faecalis. Disclosures All Authors: No reported disclosures

scholarly journals Pathophysiology of Atherosclerotic Plaque Development-Contemporary Experience and New Directions in Research

2021 ◽  
Vol 22 (7) ◽  
pp. 3513
Author(s):  
Michal Kowara ◽  
Agnieszka Cudnoch-Jedrzejewska
Keyword(s):  
Atherosclerotic Plaque ◽  
Molecular Mechanisms ◽  
Cellular Heterogeneity ◽  
Ldl Oxidation ◽  
Plaque Development ◽  
New Directions ◽  
Life Threatening ◽  
Non Coding Rnas ◽  
Cellular Pathways ◽  
Key Aspects

Atherosclerotic plaque is the pathophysiological basis of important and life-threatening diseases such as myocardial infarction. Although key aspects of the process of atherosclerotic plaque development and progression such as local inflammation, LDL oxidation, macrophage activation, and necrotic core formation have already been discovered, many molecular mechanisms affecting this process are still to be revealed. This minireview aims to describe the current directions in research on atherogenesis and to summarize selected studies published in recent years—in particular, studies on novel cellular pathways, epigenetic regulations, the influence of hemodynamic parameters, as well as tissue and microorganism (microbiome) influence on atherosclerotic plaque development. Finally, some new and interesting ideas are proposed (immune cellular heterogeneity, non-coding RNAs, and immunometabolism) which will hopefully bring new discoveries in this area of investigation.

scholarly journals Molecular Basis of Macrolide Resistance inCampylobacterStrains Isolated from Poultry in South Korea

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Bai Wei ◽  
Min Kang
Keyword(s):  
Molecular Mechanisms ◽  
Macrolide Resistance ◽  
23S Rrna ◽  
Rrna Gene ◽  
Campylobacter Coli ◽  
Erythromycin Resistance ◽  
23S Rrna Gene ◽  
Ribosomal Protein L22 ◽  
Resistant Strains ◽  
Azithromycin Resistance

We investigated the molecular mechanisms underlying macrolide resistance in 38 strains ofCampylobacterisolated from poultry. Twenty-seven strains were resistant to azithromycin and erythromycin, five showed intermediate azithromycin resistance and erythromycin susceptibility, and six showed azithromycin resistance and erythromycin susceptibility. FourCampylobacter jejuniand sixCampylobacter colistrains had azithromycin MICs which were 8–16 and 2–8-fold greater than those of erythromycin, respectively. The A2075G mutation in the 23S rRNA gene was detected in 11 resistant strains with MICs ranging from 64 to ≥ 512μg/mL. Mutations including V137A, V137S, and a six-amino acid insertion (114-VAKKAP-115) in ribosomal protein L22 were detected in theC. jejunistrains. Erythromycin ribosome methylase B-erm(B) was not detected in any strain. All strains except three showed increased susceptibility to erythromycin with twofold to 256-fold MIC change in the presence of phenylalanine arginine ß-naphthylamide (PAßN); the effects of PAßN on azithromycin MICs were limited in comparison to those on erythromycin MICs, and 13 strains showed no azithromycin MIC change in the presence of PAßN. Differences between azithromycin and erythromycin resistance and macrolide resistance phenotypes and genotypes were observed even in highly resistant strains. Further studies are required to better understand macrolide resistance inCampylobacter.

scholarly journals Resistance Response of Maize Germplasm to Downy Mildew [Peronosclerospora philipinensis]

2018 ◽  
Vol 24 (1) ◽  
pp. 43
Author(s):  
Syahrir Pakki ◽  
Mappaganggang Mappaganggang
Keyword(s):  
Downy Mildew ◽  
Block Design ◽  
Susceptible Variety ◽  
Resistant Variety ◽  
Average Intensity ◽  
Standard Score ◽  
Resistance Response ◽  
Maize Germplasm ◽  
Randomized Block Design ◽  
Moderately Resistant

<p>Two experiments to study responses of resistance of maize germplasm to downy mildew (Peronosclerospora philipinensis) have been conducted. Both experiments were arranged in randomized block design with two replication. The treatments in each experiment (2014 and 2016) were 70 maize accessions. The accessions were planted in planting distant of 75 cm × 20 cm, in 5 m rows, resulting in 20 plants per row. In every 10 rows, two check varieties were planted, i.e. one susceptible and one resistant variety. Ten days prior to planting, the soil was fertilized with mixed fertilizers consisted of urea, ZA, SP36, and KCl at a dose of 100, 100, 100, and 100 kg/ha, respectively. Fertilization II and III was given at 30 days after planting, and 45 days after planting with a dose of 100 kg urea/ha. As a source of inoculum downy mildew, around the repeated plot was planted with varieties Anoman variety (susceptible variety) that was inoculated with a suspension of downy mildew pathogen. Observation was conducted at 25, 35, and 55 days after planting, with the standard score of resistant to downy mildew, followed: 0–10% = resistant, 11–25% = moderately resistant, 26–50% = moderately susceptible, &gt;50% = susceptible. The result of the experiments showed that there were 5 accessions resistant to downy mildew (P. philipinensis), i.e. CML 440×MR4-9-30-3, 664, 60, 572, and 554 with the intensity of downy mildew infection ranged from 5 to 10%. Twelve other accessions were classified as moderately resistant, i.e. CML 440×MR4-9-98-2, 440×MR4-9-98-4 CML, CML 440×MR4-9-124-1, 66, 71, 319, 108, 73, 48, 105, 554, and 682 with intensity of infection ranged from 13 to 25%. At the same experiments, the average intensity of downy mildew infection on susceptible check varieties reached 100 percent.</p>

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