scholarly journals MinION Nanopore-based detection of Clavibacter nebraskensis, the corn Goss’s wilt pathogen, and bacteriomic profiling of necrotic lesions of naturally-infected leaf samples

PLoS ONE ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. e0245333
Author(s):  
Renlin Xu ◽  
Lorne Adam ◽  
Julie Chapados ◽  
Atta Soliman ◽  
Fouad Daayf ◽  
...  
Keyword(s):  
Relative Abundance ◽  
Bacterial Wilt ◽  
Community Dynamics ◽  
Detection System ◽  
Infected Leaf ◽  
Bacterial Wilt Disease ◽  
Healthy Leaf ◽  
The Usa ◽  
Symptomatic Leaf ◽  
Run Time

The Goss’s bacterial wilt pathogen, Clavibacter nebraskensis, of corn is a candidate A1 quarantine organism; and its recent re-emergence and spread in the USA and Canada is a potential biothreat to the crop. We developed and tested an amplicon-based Nanopore detection system for C. nebraskensis (Cn), targeting a purine permease gene. The sensitivity (1 pg) of this system in mock bacterial communities (MBCs) spiked with serially diluted DNA of C. nebraskensis NCPPB 2581T is comparable to that of real-time PCR. Average Nanopore reads increased exponentially from 125 (1pg) to about 6000 reads (1000 pg) after a 3-hr run-time, with 99.0% of the reads accurately assigned to C. nebraskensis. Three run-times were used to process control MBCs, Cn-spiked MBCs, diseased and healthy leaf samples. The mean Nanopore reads doubled as the run-time is increased from 3 to 6 hrs while from 6 to 12 hrs, a 20% increment was recorded in all treatments. Cn-spiked MBCs and diseased corn leaf samples averaged read counts of 5,100, 11,000 and 14,000 for the respective run-times, with 99.8% of the reads taxonomically identified as C. nebraskensis. The control MBCs and healthy leaf samples had 47 and 14 Nanopore reads, respectively. 16S rRNA bacteriomic profiles showed that Sphingomonas (22.7%) and Clavibacter (21.2%) were dominant in diseased samples while Pseudomonas had only 3.5% relative abundance. In non-symptomatic leaf samples, however, Pseudomonas (20.0%) was dominant with Clavibacter at 0.08% relative abundance. This discrepancy in Pseudomonas abundance in the samples was corroborated by qPCR using EvaGreen chemistry. Our work outlines a new useful tool for diagnosis of the Goss’s bacterial wilt disease; and provides the first insight on Pseudomonas community dynamics in necrotic leaf lesions.

scholarly journals Screening Tomato Genotypes for Bacterial Wilt Disease (Ralstonia solanacearum) Resistance in Ghana

2021 ◽  
Vol 3 (5) ◽  
pp. 1-8
Author(s):  
Isaac Newton B-Mensah ◽  
Kingsley Osei ◽  
Ruth N. A. Prempeh
Keyword(s):  
Bacterial Wilt ◽  
Ralstonia Solanacearum ◽  
Hot Spot ◽  
Wilt Disease ◽  
Dilution Method ◽  
Causal Organism ◽  
Bacterial Wilt Disease ◽  
The Usa ◽  
The University ◽  
Tomato Genotypes

Thirteen-tomato genotypes were assembled from the USA, Taiwan and Ghana for screening for bacterial wilt resistance in two environments: in a screen house at Crops Research Institute, Kumasi, Ghana and in the field at a bacterial wilt hot spot at Bechem in the Brong-Ahafo region of Ghana. The bacterium, Ralstonia solanacearum was isolated using the serial dilution method on Nutrient Agar (NA) and aseptically cultured for inoculation. The bacterium was implicated as the causal organism of the bacterial wilt disease of tomato. A local check, Petofake and H7996 were used as susceptible and resistant checks respectively. Three genotypes, H7996, LA0442 and LA0443 demonstrated significant resistance stability in both experimental environments by recording significantly low wilt incidence and severity. H7996 was obtained from the World Vegetable Centre (WVC), Taiwan while the other two genotypes were collected from the University of California, Davis, USA. Apart from the highest yielding genotype LA 0442 that recorded 50.67 t/h, the rest recorded very low yields. The lowest yielding genotype AVTO 1713, recorded (12.67 t/h). Thus, the highest yielding genotype, LA 0442 over-yielded the lowest AVTO1713 by approximately 300%. It is instructive to note that LA0442, which was identified as a stable resistant genotype also recorded the highest yield. This result supports the potential of developing a resistant, high yielding variety using LA0442 as a parent. The future of the tomato industry in Ghana therefore looks promising.

scholarly journals Pseudomonas Inoculation Stimulates Endophytic Azospira Population and Induces Systemic Resistance to Bacterial Wilt

2021 ◽  
Vol 12 ◽  
Author(s):  
Xian-chao Shang ◽  
Xianjie Cai ◽  
Yanan Zhou ◽  
Xiaobin Han ◽  
Cheng-Sheng Zhang ◽  
...  
Keyword(s):  
Relative Abundance ◽  
Bacterial Wilt ◽  
Bacterial Communities ◽  
Keystone Species ◽  
Acc Oxidase ◽  
Disease Suppression ◽  
Systemic Resistance ◽  
Marker Genes ◽  
Tobacco Plants ◽  
Bacterial Wilt Disease

Bacterial communities in the rhizosphere play an important role in sustaining plant growth and the health of diverse soils. Recent studies have demonstrated that microbial keystone taxa in the rhizosphere microbial community are extremely critical for the suppression of diseases. However, the mechanisms involved in disease suppression by keystone species remain unclear. The present study assessed the effects of three Pseudomonas strains, which were identified as keystone species in our previous study, on the growth performance and root-associated bacterial community of tobacco plants. A high relative abundance of Ralstonia was found in the non-inoculated group, while a large Azospira population was observed in all groups inoculated with the three Pseudomonas strains. Correspondingly, the activities of the defense-related enzymes and the expression levels of the defense signaling marker genes of the plant were increased after inoculation with the Pseudomonas strains. Moreover, the correlation analyses showed that the relative abundance of Azospira, the activity of superoxide dismutase, catalase, and polyphenol oxidase, and the expression of H1N1, ACC Oxidase, and PR1 a/c had a significantly negative (p<0.05) relationship with the abundance of Ralstonia. This further revealed that the keystone species, such as Pseudomonas spp., can suppress bacterial wilt disease by enhancing the systemic resistance of tobacco plants.

Evaluation of seed associated endophytic bacteria from tolerant chilli cv. Firingi Jolokia for their biocontrol potential against bacterial wilt disease

2021 ◽  
pp. 126751
Author(s):  
Bhaskar Dowarah ◽  
Heena Agarwal ◽  
Debasish B Krishnatreya ◽  
Pankaj Losan Sharma ◽  
Nilamjyoti Kalita ◽  
...  
Keyword(s):  
Bacterial Wilt ◽  
Endophytic Bacteria ◽  
Wilt Disease ◽  
Bacterial Wilt Disease ◽  
Biocontrol Potential

scholarly journals Ralstonia solanacearum Needs Motility for Invasive Virulence on Tomato

2001 ◽  
Vol 183 (12) ◽  
pp. 3597-3605 ◽  
Author(s):  
Julie Tans-Kersten ◽  
Huayu Huang ◽  
Caitilyn Allen
Keyword(s):  
Bacterial Wilt ◽  
Ralstonia Solanacearum ◽  
Soft Agar ◽  
Cell Protein ◽  
In Planta ◽  
Tomato Plants ◽  
Bacterial Wilt Disease ◽  
Virulence Assay ◽  
Flagellar Filament

ABSTRACT Ralstonia solanacearum, a widely distributed and economically important plant pathogen, invades the roots of diverse plant hosts from the soil and aggressively colonizes the xylem vessels, causing a lethal wilting known as bacterial wilt disease. By examining bacteria from the xylem vessels of infected plants, we found thatR. solanacearum is essentially nonmotile in planta, although it can be highly motile in culture. To determine the role of pathogen motility in this disease, we cloned, characterized, and mutated two genes in the R. solanacearum flagellar biosynthetic pathway. The genes for flagellin, the subunit of the flagellar filament (fliC), and for the flagellar motor switch protein (fliM) were isolated based on their resemblance to these proteins in other bacteria. As is typical for flagellins, the predicted FliC protein had well-conserved N- and C-terminal regions, separated by a divergent central domain. The predicted R. solanacearum FliM closely resembled motor switch proteins from other proteobacteria. Chromosomal mutants lackingfliC or fliM were created by replacing the genes with marked interrupted constructs. Since fliM is embedded in the fliLMNOPQR operon, the aphAcassette was used to make a nonpolar fliM mutation. Both mutants were completely nonmotile on soft agar plates, in minimal broth, and in tomato plants. The fliC mutant lacked flagella altogether; moreover, sheared-cell protein preparations from the fliC mutant lacked a 30-kDa band corresponding to flagellin. The fliM mutant was usually aflagellate, but about 10% of cells had abnormal truncated flagella. In a biologically representative soil-soak inoculation virulence assay, both nonmotile mutants were significantly reduced in the ability to cause disease on tomato plants. However, the fliC mutant had wild-type virulence when it was inoculated directly onto cut tomato petioles, an inoculation method that did not require bacteria to enter the intact host from the soil. These results suggest that swimming motility makes its most important contribution to bacterial wilt virulence in the early stages of host plant invasion and colonization.

Genetics of tolerance to bacterial wilt disease in tomato (Solanum lycopersicum L.)

2018 ◽  
Vol 47 (6) ◽  
pp. 591-600
Author(s):  
Brati Acharya ◽  
Ankit Kumar Ghorai ◽  
Subhramalya Dutta ◽  
Praveen Kumar Maurya ◽  
Subrata Dutta ◽  
...  
Keyword(s):  
Solanum Lycopersicum ◽  
Bacterial Wilt ◽  
Wilt Disease ◽  
Bacterial Wilt Disease ◽  
Solanum Lycopersicum L
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