scholarly journals Changing Host Photosynthetic, Carbohydrate, and Energy Metabolisms Play Important Roles in Phytoplasma Infection

2018 ◽  
Vol 108 (9) ◽  
pp. 1067-1077 ◽  
Author(s):  
Chaoling Xue ◽  
Zhiguo Liu ◽  
Li Dai ◽  
Jiaodi Bu ◽  
Mengjun Liu ◽  
...  
Keyword(s):  
High Performance ◽  
Plant Diseases ◽  
Phloem Tissue ◽  
Disease Symptoms ◽  
Transmission Electron ◽  
Stroma Lamellae ◽  
Glucose Synthesis ◽  
Broom Disease ◽  
Phytoplasma Infection ◽  
Ziziphus Jujuba

Phytoplasmas parasitize plant phloem tissue and cause many economically important plant diseases. Jujube witches’-broom disease is a destructive phytoplasma disease of Chinese jujube (Ziziphus jujuba). To elucidate the influence of phytoplasma on host photosynthetic, carbohydrate and energy metabolisms, four types of jujube tissues showing disease symptoms with different severity were investigated at the structural, physiological, and molecular levels. Quantitative real-time PCR and high-performance liquid chromatography results showed that the down-regulation of genes related to photosynthesis and the lower contents of chlorophyll in diseased leaves. This clearly inhibited the light-harvesting and photosystem II activity of photosynthesis; however, overexpression of genes related to starch, sucrose and glucose synthesis led to higher contents of these carbohydrates. Meanwhile, transmission electron microscopy images revealed that dense amounts of phytoplasmas accumulated in the sieve elements of diseased petiole phloem, and the structure of the grana and stroma lamellae of chloroplasts in the diseased leaves was destroyed. Phytoplasma infection inhibited photosynthesis and led to abnormal carbohydrate accumulation in the diseased leaves. Furthermore, comparative metabolite analysis indicated that phytoplasma infection also stimulated amino acids and energy metabolisms of the diseased leaves. Continually inhibiting the photosynthetic process and stimulating carbohydrate and energy metabolisms of diseased trees may exhaust their nutrients. Our results highlight the importance of changing host metabolisms during the pathogenic process.

Detection, Identification and Molecular Characterization of a 16SrII-V subgroup Phytoplasma Associated with Nicotiana plumbaginifolia Viviani

Plant Disease ◽  
2021 ◽  
Author(s):  
Pei-Qing Liao ◽  
Yuh-Kun Chen ◽  
Helen Mae Mejia ◽  
Yuanyu Chien ◽  
Ya-Chien Lee ◽  
...  
Keyword(s):  
Agricultural Sector ◽  
Nicotiana Plumbaginifolia ◽  
Herbaceous Plant ◽  
Disease Symptoms ◽  
Transmission Electron ◽  
Rapid Spread ◽  
Phytoplasma Infection ◽  
Sieve Tubes ◽  
Virtual Rflp ◽  
Solanaceae Family

Nicotiana plumbaginifolia Viviani or commonly known as curl-leaved tobacco is an annual herbaceous plant belonging to Solanaceae family. This plant is native to Mexico, South America, and parts of the Caribbean and has been reported to be present in Taiwan since 2006. In March 2021, N. plumbaginifolia Viviani found in Yunlin County, Taiwan was observed to have phyllody, virescence, and witches’-broom which is consistent with the disease symptoms caused by phytoplasma infection. Samples of the healthy and symptomatic plants were collected for analysis of the causal agent associated with the diseased N. plumbaginifolia Viviani. Under transmission electron microscopy, the phytoplasma-like pleomorphic bodies were found in the sieve tubes of the diseased plants. The 16S rRNA-based phylogenetic analysis and the iPhyClassifier-based virtual RFLP study demonstrated that the phytoplasma identified in this study can be classified into the 16SrII-V subgroup, which is similar to the peanut witches’-broom phytoplasma, a ‘Candidatus phytoplasma aurantifolia’-related strain. Further identification of SAP54/PHYL1 and SAP11 homologues in the phytoplasma explain the disease symptoms of phyllody, virescence, and witches’-broom observed in diseased N. plumbaginifolia Viviani. The discovery of new phytoplasma plant hosts has gained scientific importance in light of the attempt to unravel an efficient strategy to fight the rapid spread of this disease which poses threat to the agricultural sector and food security in Taiwan.

scholarly journals Three Main Genes in the MAPK Cascade Involved in the Chinese Jujube-Phytoplasma Interaction

Forests ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 392 ◽  
Author(s):  
Zhiguo Liu ◽  
Zhihui Zhao ◽  
Chaoling Xue ◽  
Lixin Wang ◽  
Lili Wang ◽  
...  
Keyword(s):  
Expression Profiles ◽  
Plant Diseases ◽  
Mitogen Activated Protein Kinase ◽  
Chinese Jujube ◽  
Mapk Cascades ◽  
Significant Difference ◽  
Mitogen Activated Protein ◽  
Plant Pathogen Interaction ◽  
Broom Disease ◽  
Phytoplasma Infection

Chinese jujube (Ziziphus jujuba Mill.) is an important economic forest species and multipurpose fruit tree in the family of Rhamnaceae. Phytoplasmas are significant prokaryotic pathogens, associated with more than 1000 plant diseases. Jujube witches’ broom disease (JWB) is a typical phytoplasma disease, caused by ‘Candidatus Phytoplasma ziziphi’. Mitogen-activated protein kinase (MAPK) cascades are highly universal signal transduction modules and play crucial roles in regulating innate immune responses in plants. Thus, in the current study, systematical expression profiles of 10 ZjMPK and 4 ZjMPKK genes were conducted in plantlets with JWB disease, plantlets recovered from JWB disease, the tissues showing different disease symptoms, and resistant/susceptible cultivars infected by JWB phytoplasma. We found that most ZjMPK and ZjMKK genes exhibited significant up- or down-regulation expression under phytoplasma infection, but the top three differentially expressed genes (DEGs) were ZjMPK2, ZjMKK2 and ZjMKK4, which showed the biggest times of gene’s significant difference expression in all materials. Based on STRING database analysis, ZjMKK2 and ZjMPK2 were involved in the same plant-pathogen interaction pathway, and Yeast two-hybrid screening showed that ZjMKK2 could interact with ZjMPK2. Finally, we deduced a pathway of jujube MAPK cascades which response to ‘Candidatus Phytoplasma ziziphi’ infection. Our study presents the first gene-family-wide investigation on the systematical expression analysis of MAPK and MAPKK genes in Chinese jujube under phytoplasma infection. These results provide valuable information for the further research on the signaling pathway of phytoplasma infection in Chinese jujube.

Identification of 16SrII-V Phytoplasma Associated with Mungbean Phyllody Disease in Taiwan

Plant Disease ◽  
2021 ◽  
Author(s):  
Yen-Ming Chen ◽  
yuanyu chien ◽  
Yuh-Kun Chen ◽  
Pei-Qing Liao ◽  
Choon-Meng Tan ◽  
...  
Keyword(s):  
16S Rrna ◽  
Disease Symptoms ◽  
Legume Crop ◽  
Transmission Electron ◽  
Broom Disease ◽  
Sieve Tubes ◽  
Virtual Rflp ◽  
Sieve Pores ◽  
Premature Germination ◽  
Microscopy Examination

Mungbean (Vigna radiata (L.) R. Wilczek), an important legume crop in Asia, is primarily cultivated in the central-southern region of western Taiwan. In 2020, mungbean exhibiting typical phytoplasma-induced disease symptoms, such as witches’ broom, phyllody, virescence, and proliferation, was observed in Yunlin County, Taiwan. Moreover, the seeds harvested from diseased plants displayed premature germination. Transmission electron microscopy examination of leaf veins prepared from symptomatic mungbeans demonstrated that the occlusion of sieve tubes resulted from the accumulation of phytoplasma-like bodies in sieve elements along with filament-like structures in sieve pores. The association of phytoplasma in symptomatic mungbean was confirmed by PCR analyses of the 16S rRNA and immunodominant membrane protein genes. Further analyses of the 16S rRNA-based phylogenetic tree and the iPhyClassifier-based virtual RFLP study demonstrated that the phytoplasma-associated mungbean phyllody disease identified in this study belongs to the 16SrII-V subgroup. BLAST analysis and the phylogenetic analysis indicated that the SAP11-like protein identified in mungbean phyllody disease is identical to PnWB phytoplasma SAP11, which explains the witches’ broom phenotype observed in symptomatic mungbean. The results described in this report confirm that the 16SrII-V phytoplasma, a widely distributed phytoplasma associated with peanut witches’ broom disease in Taiwan, has also infected mungbean. This is not only the first instance of mungbean phyllody disease found in Taiwan, but also the first instance of mungbean phyllody disease causing by 16SrII-V subgroup phytoplasma.

scholarly journals Novel effector recognition capacity engineered into a paired NLR complex

2021 ◽  
Author(s):  
Shanshan Wang ◽  
Weijie Huang ◽  
Zane Duxbury ◽  
Saskia Adriane Hogenhout ◽  
Jonathan DG Jones
Keyword(s):  
Receptor Gene ◽  
Plant Diseases ◽  
Host Protein ◽  
Host Proteins ◽  
Disease Symptoms ◽  
Specific Host ◽  
Pathogen Effector ◽  
Phytoplasma Infection ◽  
S Allele ◽  
Effector Recognition

The Arabidopsis RRS1-R Resistance gene confers recognition of the bacterial acetyltransferase PopP2 and another bacterial effector, AvrRps4. The RRS1-S allele recognizes AvrRps4 but not PopP2. RRS1-R/RRS1-S heterozygotes cannot recognize PopP2. RRS1-R and RRS1-S also suppress the constitutive RPS4-dependent autoactivity of RRS1-Rslh1. Phytoplasmas cause important plant diseases, and their effectors can cause degradation of specific host proteins. We tested whether attaching a pathogen effector-dependent degron to RRS1-R, enabling its degradation by phytoplasma effector SAP05, could derepress RRS1-Rslh1 autoactivity, resulting in SAP05-dependent resistance. In transient assays in tobacco, RRS1-R-derived constructs can confer a hypersensitive response (HR) to SAP05. However, phytoplasma infection assays in transgenic Arabidopsis resulted in delayed disease symptoms but not full resistance. We provide a proof-of-concept strategy utilizing the recessiveness of a plant immune receptor gene to engineer recognition of a pathogen effector that promotes degradation of a specific host protein.

Prospects for convergent beam electron diffraction with a 200kV cold field-emission transmission electron microscope

1991 ◽  
Vol 49 ◽  
pp. 466-467
Author(s):  
J W Steeds ◽  
R Vincent
Keyword(s):  
Field Emission ◽  
High Performance ◽  
Small Diameter ◽  
Convergent Beam Electron Diffraction ◽  
Zone Axis ◽  
Medium Voltage ◽  
Transmission Electron ◽  
Good Crystallinity ◽  
Special Modification ◽  
Convergent Beam

We review the analytical powers which will become more widely available as medium voltage (200-300kV) TEMs with facilities for CBED on a nanometre scale come onto the market. Of course, high performance cold field emission STEMs have now been in operation for about twenty years, but it is only in relatively few laboratories that special modification has permitted the performance of CBED experiments. Most notable amongst these pioneering projects is the work in Arizona by Cowley and Spence and, more recently, that in Cambridge by Rodenburg and McMullan.There are a large number of potential advantages of a high intensity, small diameter, focussed probe. We discuss first the advantages for probes larger than the projected unit cell of the crystal under investigation. In this situation we are able to perform CBED on local regions of good crystallinity. Zone axis patterns often contain information which is very sensitive to thickness changes as small as 5nm. In conventional CBED, with a lOnm source, it is very likely that the information will be degraded by thickness averaging within the illuminated area.

scholarly journals Novel Carbon Dots Derived from Glycyrrhizae Radix et Rhizoma and Their Anti-Gastric Ulcer Effect

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1512
Author(s):  
Yuhan Liu ◽  
Meiling Zhang ◽  
Jinjun Cheng ◽  
Yue Zhang ◽  
Hui Kong ◽  
...  
Keyword(s):  
Gastric Ulcer ◽  
Photoelectron Spectroscopy ◽  
Carbon Dots ◽  
High Performance ◽  
Raw264.7 Cells ◽  
Mice Model ◽  
X Ray ◽  
Glycyrrhizae Radix ◽  
Transmission Electron ◽  
High Resolution Tem

Glycyrrhizae Radix et Rhizoma (GRR) is one of the commonly used traditional Chinese medicines in clinical practice, which has been applied to treat digestive system diseases for hundreds of years. GRR is preferred for anti-gastric ulcer, however, the main active compounds are still unknown. In this study, GRR was used as precursor to synthesize carbon dots (CDs) by a environment-friendly one-step pyrolysis process. GRR-CDs were characterized by using transmission electron microscopy, high-resolution TEM, fourier transform infrared, ultraviolet-visible and fluorescence spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction and high-performance liquid chromatography. In addition, cellular toxicity of GRR-CDs was studied by using CCK-8 in RAW264.7 cells, and the anti-gastric ulcer activity was evaluated and confirmed using mice model of acute alcoholic gastric ulcer. The experiment confirmed that GRR-CDs were the spherical structure with a large number of active groups on the surface and their particle size ranged from 2 to 10 nm. GRR-CDs had no toxicity to RAW264.7 cells at concentration of 19.5 to 5000 μg/mL and could reduce the oxidative damage of gastric mucosa and tissues caused by alcohol, as demonstrated by restoring expression of malondialdehyde, superoxide dismutase and nitric oxide in serum and tissue of mice. The results indicated the explicit anti-ulcer activity of GRR-CDs, which provided a new insights for the research on effective material basis of GRR.

scholarly journals Skipping the Insect Vector: Plant Stolon Transmission of the Phytopathogen ‘Ca. Phlomobacter fragariae’ from the Arsenophonus Clade of Insect Endosymbionts

Insects ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 93
Author(s):  
Jessica Dittmer ◽  
Thierry Lusseau ◽  
Xavier Foissac ◽  
Franco Faoro
Keyword(s):  
Plant Pathogens ◽  
Model Systems ◽  
Insect Vector ◽  
Evolutionary Perspective ◽  
Evolutionary Transition ◽  
Strawberry Plant ◽  
Disease Symptoms ◽  
Transmission Electron ◽  
Nutrient Provisioning ◽  
Early Growth Phase

The genus Arsenophonus represents one of the most widespread clades of insect endosymbionts, including reproductive manipulators and bacteriocyte-associated primary endosymbionts. Two strains belonging to the Arsenophonus clade have been identified as insect-vectored plant pathogens of strawberry and sugar beet. The bacteria accumulate in the phloem of infected plants, ultimately causing leaf yellows and necrosis. These symbionts therefore represent excellent model systems to investigate the evolutionary transition from a purely insect-associated endosymbiont towards an insect-vectored phytopathogen. Using quantitative PCR and transmission electron microscopy, we demonstrate that ‘Candidatus Phlomobacter fragariae’, bacterial symbiont of the planthopper Cixius wagneri and the causative agent of Strawberry Marginal Chlorosis disease, can be transmitted from an infected strawberry plant to multiple daughter plants through stolons. Stolons are horizontally growing stems enabling the nutrient provisioning of daughter plants during their early growth phase. Our results show that Phlomobacter was abundant in the phloem sieve elements of stolons and was efficiently transmitted to daughter plants, which rapidly developed disease symptoms. From an evolutionary perspective, Phlomobacter is, therefore, not only able to survive within the plant after transmission by the insect vector, but can even be transmitted to new plant generations, independently from its ancestral insect host.

Preparation of yolk–shell structured Ag@Cu particles and their application in high performance electrochemical sensing of p-aminobenzoic acid

2019 ◽  
Vol 97 (2) ◽  
pp. 140-146
Author(s):  
Tian Gan ◽  
Zhikai Wang ◽  
Mengru Chen ◽  
Wanqiu Fu ◽  
Haibo Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
High Performance ◽  
Electrochemical Impedance ◽  
High Sensitivity ◽  
Differential Pulse ◽  
Electrochemical Sensing ◽  
High Catalytic Activity ◽  
Aminobenzoic Acid ◽  
Transmission Electron

In this work, the Ag@Cu particles with yolk–shell nanostructure was prepared by facile solvothermal method, which was modified on glassy carbon electrode (GCE) to fabricate electrochemical sensor for the convenient and fast determination of p-aminobenzoic acid (PABA). The surface morphology and electrochemical properties of the as-prepared Ag@Cu nanocomposite modified electrode were characterized by scanning electron microscopy, transmission electron microscopy, chronocoulometry, and electrochemical impedance spectroscopy. Further, the electrochemical sensing of PABA was performed on the Ag@Cu/GCE using cyclic voltammetry and differential pulse voltammetry techniques, showing high catalytic activity. Under the optimal conditions, the sensor exhibited a wide linear range, high sensitivity, and low detection limit of 0.315 μmol/L for PABA. The developed sensor was also successfully applied for PABA detection in anesthetic and cosmetics with satisfactory results.

The Effect of Water Vapor on Oxidation Performance of Alloys Used in Recuperators

2002 ◽  
Author(s):  
Bruce A. Pint ◽  
Karren L. More ◽  
Peter F. Tortorelli
Keyword(s):  
Water Vapor ◽  
High Performance ◽  
Waste Heat ◽  
Alumina Scale ◽  
Effect Of Water ◽  
Transmission Electron ◽  
Transmission Electron Microscopy Characterization ◽  
Surface Oxides ◽  
Oxidation Performance ◽  
Microscopy Characterization

The use of a recuperator to recover waste heat from the exhaust gases is one method for improving a microturbine’s energy efficiency. This study looked at the effect of water vapor in the exhaust gas on the oxidation resistance of a current technology stainless steel and several high performance replacement alloys. Alloys of interest are high-Cr, Ni-base superalloys such as alloy 625 and aluminum-containing alloys such as Haynes alloy 214 and Plansee alloy PM2000, which is an oxide-dispersed FeCrAl. The latter two alloys form a protective external alumina scale which is more resistant to water vapor environments than chromia scales. Scanning and transmission electron microscopy characterization of the specimen surface oxides after laboratory exposures showed only minor effects of the addition of water vapor to the environment, which is consistent with the excellent corrosion resistance of these high performance alloys.

scholarly journals Sistem Pakar Diagnosa Penyakit Pohon Karet dengan Metode Certainty Factor

2019 ◽  
Vol 4 (2) ◽  
pp. 19
Author(s):  
Anita Sindar R M Sinaga
Keyword(s):  
Expert Systems ◽  
Plant Diseases ◽  
Certainty Factor ◽  
Disease Symptoms ◽  
Rubber Plant ◽  
Factor Method ◽  
Data Process ◽  
System Data ◽  
Type Data ◽  
Output Information

The low production of smallholder rubber is caused by various factors, one of the causes is interference from various diseases. Building a system (computer) that is intelligent to analyze problems, observe the work system of an expert or expert. Expertise comes from the development of knowledge of someone who is competent and directly provides instructions to solve a problem. Certainty Factor is a method to prove whether a fact is certain or not certain in the form of metrics that are usually used in expert systems. This method is very suitable for expert systems that diagnose something that is uncertain. To apply the Certainty Factor method to the expert system, data is needed that will be input into the system, processed and display the results of the diagnosis of rubber plant diseases.  Input: rubber plant disease type data and disease symptom data. Process: carry out analysis and calculation to get the diagnosis results using the Certainty Factor method. Output: information on the diagnosis of rubber plant diseases and percentage of confidence level in the diagnosis results in accordance with the rules of the Certainty Factor method. Keywords : Rubber Disease, Symptoms Diagnosis, Value Combination, Certainty Factor   

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