MORPHOLOGY, NUTRITION, AND HOST RANGE OF A SPECIES OF PYTHIUM

1963 ◽  
Vol 9 (4) ◽  
pp. 451-457 ◽  
Author(s):  
R. H. Haskins
Keyword(s):  
Soft Rot ◽  
Ustilago Maydis ◽  
Morning Glory ◽  
Root Tips ◽  
Wide Range ◽  
Extractable Substance ◽  
Green Pea ◽  
Sexual Stages ◽  
Host Tissues ◽  
Sweet Pea

A species of Pythium (probably P. acanthicum Drechs.) is described which is able to parasitize 80% of a wide range of 98 species of fungi tested. Nine of the test fungi were not parasitized, and 10 actively inhibited the Pythium, with Ustilago maydis exhibiting the strongest inhibition. The roots of sunflower, corn, wheat, flax, beet, morning glory, sweet pea, Polish rape, and green pea were attacked, producing browning of the root tips. The organism produced a rapid, watery soft rot when inoculated into cucumber and potatoes. The organism requires a fat-solvent extractable substance for development of its sexual stages. It can obtain this substance from both living and dead host tissues, but not from its own killed vegetative mycelium.

scholarly journals Mortality of Potato Psyllid (Hemiptera: Triozidae) on Host Clippings Inoculated With Ergot Alkaloids

2020 ◽  
Vol 113 (5) ◽  
pp. 2079-2085
Author(s):  
Navneet Kaur ◽  
W Rodney Cooper ◽  
Jennifer M Duringer ◽  
Arash Rashed ◽  
Ismael E Badillo-Vargas ◽  
...  
Keyword(s):  
Ergot Alkaloids ◽  
Morning Glory ◽  
Potato Psyllid ◽  
Bactericera Cockerelli ◽  
Artificial Diets ◽  
Synthetic Compounds ◽  
Potato Plants ◽  
Ipomoea Tricolor ◽  
Crude Extracts ◽  
Host Tissues

Abstract Our previous study provided correlative evidence that morning glory species harboring endophytic fungi (Periglandula) are resistant to potato psyllid [Bactericera cockerelli (Šulc)], whereas species free of fungi often allowed psyllid development. In this study, we manipulated levels of ergot alkaloids in host tissues by inoculating clippings from potato plants with extracts from morning glories that harbor Periglandula [Ipomoea leptophylla Torrey, Ipomoea imperati (Vahl) Grisebach, Ipomoea tricolor Cavanilles, Ipomoea pandurata (L.) G. F. Meyer, and Turbina corymbosa (L.)] and one species (Ipomoea alba L.) that does not harbor the endophyte. Ergot alkaloids (clavines, lysergic acid amides, and ergopeptines) were detected in potato clippings, thus confirming that leaves had taken up compounds from solutions of crude extracts. Psyllid mortality rates on inoculated clippings ranged between 53 and 93% in treatments producing biochemically detectable levels of alkaloids, when compared with 15% mortality in water controls or the alkaloid-free I. alba. We then tested synthetic analogs from each of the three alkaloid classes that had been detected in the crude extracts. Each compound was assayed by inoculating clippings of two host species (potato and tomato) at increasing concentrations (0, 1, 10, and 100 µg/ml in solution). Psyllids exhibited a large and significant increase in mortality rate beginning at the lowest two concentrations, indicating that even very small quantities of these chemicals led to mortality. Feeding by nymphs on artificial diets containing synthetic compounds resulted in 100% mortality within 48 h, irrespective of compound. Further testing of ergot alkaloids to characterize the mode of action that leads to psyllid mortality is warranted.

scholarly journals Screening, Identification and Efficacy Evaluation of Antagonistic Bacteria for Biocontrol of Soft Rot Disease Caused by Dickeya zeae

2020 ◽  
Vol 8 (5) ◽  
pp. 697 ◽  
Author(s):  
Jieling Li ◽  
Ming Hu ◽  
Yang Xue ◽  
Xia Chen ◽  
Guangtao Lu ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Prevention And Control ◽  
Pathogenic Bacteria ◽  
Soft Rot ◽  
Antagonistic Bacteria ◽  
Bacterial Soft Rot ◽  
Soft Rot Disease ◽  
Wide Range ◽  
Rot Disease ◽  
And Control

Dickeya zeae is the causal agent of bacterial soft rot disease, with a wide range of hosts all over the world. At present, chemical agents, especially agricultural antibiotics, are commonly used in the prevention and control of bacterial soft rot, causing the emergence of resistant pathogens and therefore increasing the difficulty of disease prevention and control. This study aims to provide a safer and more effective biocontrol method for soft rot disease caused by D. zeae. The spot-on-lawn assay was used to screen antagonistic bacteria, and three strains including SC3, SC11 and 3-10 revealed strong antagonistic effects and were identified as Pseudomonas fluorescens, P. parafulva and Bacillus velezensis, respectively, using multi-locus sequence analysis (MLSA) based on the sequences of 16S rRNA and other housekeeping genes. In vitro antimicrobial activity showed that two Pseudomonas strains SC3 and SC11 were only antagonistic to some pathogenic bacteria, while strain 3-10 had broad-spectrum antimicrobial activity on both pathogenic bacteria and fungi. Evaluation of control efficacy in greenhouse trials showed that they all restrained the occurrence and development of soft rot disease caused by D. zeae MS2 or EC1. Among them, strain SC3 had the most impressive biocontrol efficacy on alleviating the soft rot symptoms on both monocotyledonous and dicotyledonous hosts, and strain 3-10 additionally reduced the occurrence of banana wilt disease caused by Fusarium oxysporum f. sp. cubensis. This is the first report of P. fluorescens, P. parafulva and B. velezensis as potential bio-reagents on controlling soft rot disease caused by D. zeae.

scholarly journals Emergence of Bacterial Soft Rot in Cucumber Caused by Pectobacterium carotovorum subsp. brasiliense in China

Plant Disease ◽  
2017 ◽  
Vol 101 (2) ◽  
pp. 279-287 ◽  
Author(s):  
Xianglong Meng ◽  
Ali Chai ◽  
Yanxia Shi ◽  
Xuewen Xie ◽  
Zhanhong Ma ◽  
...  
Keyword(s):  
Sequence Analysis ◽  
Soft Rot ◽  
Economic Losses ◽  
Pectobacterium Carotovorum ◽  
Bacterial Soft Rot ◽  
Bacterial Strains ◽  
Phenotypic Properties ◽  
Gene Sequence Analysis ◽  
Wide Range ◽  
Carotovorum Subsp

During 2014 to 2015, a devastating bacterial soft rot on cucumber stems and leaves occurred in Shandong, Shanxi, Hebei, Henan, and Liaoning provinces of China, resulting in serious economic losses for cucumber production. The gummosis emerged on the surface of leaves, stems, petioles, and fruit of cucumber. The basal stem color was dark brown and the stem base turned to wet rot. Yellow spots and wet rot emerged at the edge of the infected cucumber leaves and gradually infected the leaf centers. In total, 45 bacterial strains were isolated from the infected tissues. On the basis of phenotypic properties of morphology, physiology, biochemistry, and 16S ribosomal RNA gene sequence analysis, the pathogen was identified as Pectobacterium carotovorum. Multilocus sequence analysis confirmed that the isolates were P. carotovorum subsp. brasiliense, and the pathogens fell in clade II. The pathogenicity of isolated bacteria strains was confirmed. The strains reisolated were the same as the original. The host range test confirmed that strains had a wide range of hosts. As far as we know, this is the first report of cucumber stem soft rot caused by P. carotovorum subsp. brasiliense in China as well as in the world, which has a significant economic impact on cucumber production.

scholarly journals A novel subspecies-specific primer targeting the gyrase B gene for the detection of Pectobacterium carotovorum subsp. brasiliense

2019 ◽  
Vol 20 (10) ◽  
Author(s):  
Tri Joko ◽  
ALAN SOFFAN ◽  
MUHAMMAD SAIFUR ROHMAN
Keyword(s):  
Sequence Data ◽  
Soft Rot ◽  
Pectobacterium Carotovorum ◽  
Specific Primer ◽  
Base Pairs ◽  
Detection And Identification ◽  
Wide Range ◽  
Carotovorum Subsp ◽  
Rot Disease ◽  
The Tropics

Abstract. Joko T, Soffan A, Muhammad Saifur Rohman MS. 2019. A novel subspecies-specific primer targeting the gyrase B gene for the detection of Pectobacterium carotovorum subsp. brasiliense. Biodiversitas 20: 3042-3048. Pectobacterium carotovorum subsp. brasiliense is one of the major causative bacterial pathogens of the soft rot disease in various crops. It has a high virulence and a wide range of hosts in the tropics and the subtropics. Most often, conventional methods are not able to accurately distinguish P. carotovorum subsp. brasiliense from other subspecies. Thus, this study aimed to design a specific gyrase B gene (gyrB) -based primers for the detection and identification of soft rot pathogen. The specific primers design was based on the alignment using gyrB gene sequence data from P. carotovorum subsp. brasiliense and other data from the GenBank. The primers comprised of F-gyr-Pcb (5’-CAC AGG CAC CGC TGG CTG TT-3’) and R-gyr-Pcb (5’-CGT CGT TCC ACT GCA ATG CCA-3’) with an amplicon of 336 base pairs. The specificity of the primers pair was verified both in silico and in polymerase chain reaction (PCR) assays, where the primers could only detect P. carotovorum subsp. brasiliense. Primers’ sensitivity was determined by qualitative PCR with a detection limit of less than 0.5 ng/µL of genomic DNA. Hence, the proposed detection tool can be beneficial to advance further studies on the ecology and epidemiology of soft rot diseases.

scholarly journals Anther Culture of Potato and Molecular Analysis of Anther-derived Plants as Laboratory Exercises for Plant Breeding Courses

1999 ◽  
Vol 9 (4) ◽  
pp. 585-588 ◽  
Author(s):  
Richard E. Veilleux
Keyword(s):  
Plant Breeding ◽  
Anther Culture ◽  
Molecular Analysis ◽  
Simple Procedure ◽  
Extraction Procedure ◽  
Basal Medium ◽  
Root Tips ◽  
Wide Range ◽  
Simple Medium

Anther culture has been one of the most successful techniques for generating haploid plants over a wide range of species. It is a reasonably simple procedure that can be accomplished successfully without sophisticated laboratory facilities; yet, the plants generated through anther culture can be used to demonstrate the application of many modern methods that have direct applicability to plant breeding. Anthers of diploid potato clones that have been selected for competence in anther culture can be cultured in a simple medium to yield androgenic embryos after 5 weeks. Plant regeneration requires an additional 3 to 4 weeks. Regenerated plants should be large enough 2 weeks after transfer to basal medium for ploidy determination by any of three methods depending on available facilities: chromosome counts in root tips; chloroplast counts in stomatal guard cells; or flow cytometry of nuclei released from in vitro plantlets. DNA can be extracted from anther-derived plantlets using a rapid extraction procedure to demonstrate segregation of PCR (polymerase chain reaction)-based markers such as RAPD (randomly amplified polymorphic DNA), RAMPs (randomly amplified microsatellite polymorphisms), or microsatellites. Microsatellite markers that were heterozygous in the anther donor can be used to verify haploidy in anther-derived plants. If an anther culture laboratory is scheduled early in a semester, such molecular analysis can be planned for late in the same semester.

scholarly journals First Report of Bacterial Soft Rot of Potato Caused by Pectobacterium carotovorum subsp. carotovorum in Guangdong Province of China

Plant Disease ◽  
2012 ◽  
Vol 96 (12) ◽  
pp. 1819-1819 ◽  
Author(s):  
J. X. Zhang ◽  
B. R. Lin ◽  
H. F. Shen ◽  
X. M. Pu ◽  
Z. N. Chen ◽  
...  
Keyword(s):  
Guangdong Province ◽  
Housekeeping Genes ◽  
Soft Rot ◽  
Bacterial Suspension ◽  
Pectobacterium Carotovorum ◽  
Bacterial Soft Rot ◽  
First Report ◽  
Wide Range ◽  
Carotovorum Subsp ◽  
Agar Media

Potato (Solanum tuberosum L.) is a major crop in China, with 80.0 million tons being produced in 2010 on 3.3 million ha. Pectobacterium carotovorum subsp. carotovorum Jones 1901; Hauben et al. 1999 causes soft rot worldwide on a wide range of hosts including potato, carrot, and cabbage. During spring 2010, a soft rot with a foul smell was noted in stored potato tubers of different cultivars in the Guangdong Province. Symptoms on tubers appeared as tan, water-soaked areas with watery ooze. The rotted tissues were white to cream colored. Stems of infected plants with typical inky black symptoms could also be found in the fields prior to harvest. Three different potato fields were surveyed, and 13% of the plants had the symptoms. Twenty-seven samples (three symptomatic tubers per sample) were collected. Bacteria were successfully isolated from all diseased tissues on nutrient agar media supplemented with 5% sucrose and incubated at 26 ± 1°C for 36 h. After purification on tripticase soy agar media, four typical strains (7-3-1, 7-3-2, 8-3-1, and 8-3-2) were identified using the following deterministic tests: gram-negative rods, oxidase negative, facultatively anaerobic, able to degrade pectate, sensitive to erythromycin, negative for phosphatase, unable to produce acid from α-methyl-glucoside, and produced acid from trehalose. Biolog analysis (Ver 4.20.05, Hayward, CA) identified the strains as P. carotovorum subsp. carotovorum (SIM 0.808, 0.774, 0.782, and 0.786, respectively). The identity of strains 7-3-1 (GenBank Accession No. JX258132), 7-3-2 (JX258133), and 8-3-1 (JX196705) was confirmed by 16S rRNA gene sequencing (4), since they had 99% sequence identity with other P. carotovorum subsp. carotovorum strains (GenBank Accession Nos. JF926744 and JF926758) using BLASTn. Further genetic analysis of strain 8-3-1 was performed targeting informative housekeeping genes, i.e., acnA (GenBank Accession No. JX196704), gabA (JX196706), icdA (JX196707), mdh (JX196708), mtlD (JX196709), pgi (JX196710), and proA (JX196711) (2). These sequences from strain 8-3-1 were 99 to 100%, homologous to sequences of multiple strains of P. carotovorum subsp. carotovorum. Therefore, strain 8-3-1 grouped with P. carotovorum subsp. carotovorum on the phylogenetic trees (neighbor-joining method, 1,000 bootstrap values) of seven concatenated housekeeping genes when compared with 60 other strains, including Pectobacterium spp. and Dickeya spp. (3). Pathogenicity of four strains (7-3-1, 7-3-2, 8-3-1, and 8-3-2) was evaluated by depositing a bacterial suspension (106 CFU/ml) on the potato slices of cultivar ‘Favorita’ and incubating at 30 ± 1°C. Slices inoculated with just water served as non-inoculated checks. The strains caused soft rot within 72 h and the checks had no rot. Bacteria were reisolated from the slices and were shown to be identical to the original strains based on morphological, cultural, and biochemical tests. Although this pathogen has already been reported in northern China (1), to our knowledge, this is the first report of P. carotovorum subsp. carotovorum causing bacterial soft rot of potato in Guangdong Province of China. References: (1) Y. X. Fei et al. J. Hexi Univ. 26:51, 2010.(2) B. Ma et al. Phytobacteriology 97:1150, 2007. (3) S. Nabhan et al. Plant Pathol. 61:498, 2012. (4) W. G. Weisbury et al. J. Bacteriol. 173:697, 1991.

scholarly journals Potential Control of Potato Soft Rot Disease by the Obligate Predators Bdellovibrio and Like Organisms

2020 ◽  
Vol 86 (6) ◽  
Author(s):  
Daniel Youdkes ◽  
Yael Helman ◽  
Saul Burdman ◽  
Ofra Matan ◽  
Edouard Jurkevitch
Keyword(s):  
Plant Pathogens ◽  
Soft Rot ◽  
Plant Diseases ◽  
Predator Population ◽  
Bacterial Soft Rot ◽  
Population Parameters ◽  
Live Prey ◽  
Content Type ◽  
Wide Range

ABSTRACT Bacterial soft rot diseases caused by Pectobacterium spp. and Dickeya spp. affect a wide range of crops, including potatoes, a major food crop. As of today, farmers mostly rely on sanitary practices, water management, and plant nutrition for control. We tested the bacterial predators Bdellovibrio and like organisms (BALOs) to control potato soft rot. BALOs are small, motile predatory bacteria found in terrestrial and aquatic environments. They prey on a wide range of Gram-negative bacteria, including animal and plant pathogens. To this end, BALO strains HD100, 109J, and a ΔmerRNA derivative of HD100 were shown to efficiently prey on various rot-causing strains of Pectobacterium and Dickeya solani. BALO control of maceration caused by a highly virulent strain of Pectobacterium carotovorum subsp. brasilense was then tested in situ using a potato slice assay. All BALO strains were highly effective at reducing disease, up to complete prevention. Effectivity was concentration dependent, and BALOs applied before P. carotovorum subsp. brasilense inoculation performed significantly better than those applied after the disease-causing agent, maybe due to in situ consumption of glucose by the prey, as glucose metabolism by live prey bacteria was shown to prevent predation. Dead predators and the supernatant of BALO cultures did not significantly prevent maceration, indicating that predation was the major mechanism for the prevention of the disease. Finally, plastic resistance to predation was affected by prey and predator population parameters, suggesting that population dynamics affect prey response to predation. IMPORTANCE Bacterial soft rot diseases caused by Pectobacterium spp. and Dickeya spp. are among the most important plant diseases caused by bacteria. Among other crops, they inflict large-scale damage to potatoes. As of today, farmers have few options to control them. The bacteria Bdellovibrio and like organisms (BALOs) are obligate predators of bacteria. We tested their potential to prey on Pectobacterium spp. and Dickeya spp. and to protect potato. We show that different BALOs can prey on soft rot-causing bacteria and prevent their growth in situ, precluding tissue maceration. Dead predators and the supernatant of BALO cultures did not significantly prevent maceration, showing that the effect is due to predation. Soft rot control by the predators was concentration dependent and was higher when the predator was inoculated ahead of the prey. As residual prey remained, we investigated what determines their level and found that initial prey and predator population parameters affect prey response to predation.

Cytogenetic Diversity and Characterization of Vicia sativa Subspecies

2020 ◽  
Author(s):  
Berk Benlioglu
Keyword(s):  
Relative Length ◽  
Chromosome Length ◽  
Asymmetry Index ◽  
Close Relative ◽  
Vicia Sativa ◽  
Root Tips ◽  
Index Analysis ◽  
Wide Range ◽  
Karyotype Asymmetry ◽  
Intrachromosomal Asymmetry

Background: Vicia sativa L. is variable genus comprised of several subspecies. Close relative species and subspecies of the cultivated species are easily usable gene sources because they have gained resistance against a wide range of biotic and abiotic stresses. The main objectives of this study are to identify and describe the cytogenetical and karyological characteristics of subspecies in the Vicia sativa complex.Methods: The research material consisted of multiple entries collected from the five subspecies of nine taxa. All cytological observations made from root tips. Six chromosomal parameters (chromosome length, relative length, long arm length, short arm length, arm ratio and centromeric index) and five karyotype asymmetric parameters (difference in relative length, total form percentage, intrachromosomal asymmetry index, interchromosomal asymmetry index and mean centromeric asymmetry) were determined.Result: It was determined that the chromosome number of subspecies were 2n =10-12. The haploid chromosome lengths of subspecies were 15.86-33.88 µm and the average chromosome lengths varied between 2.64-5.65 µm. According to the intrachromosomal karyotype asymmetry index analysis, subsp. segetalis was the most asymmetric karyotype and subsp. sativa “Antalya” was the most symmetric karyotype. According to the interchromosomal karyotype asymmetry index analysis, subsp. angustifolia was the most asymmetric karyotype and subsp. nigra was the most symmetric karyotype.

scholarly journals Integrated strain- and process design enable production of 220 g L−1 itaconic acid with Ustilago maydis

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Hamed Hosseinpour Tehrani ◽  
Johanna Becker ◽  
Isabel Bator ◽  
Katharina Saur ◽  
Svenja Meyer ◽  
...  
Keyword(s):  
Itaconic Acid ◽  
Acid Production ◽  
Process Development ◽  
Ustilago Maydis ◽  
Integrated Approach ◽  
Strain Engineering ◽  
Total Acid ◽  
Regulatory Cascade ◽  
Wide Range ◽  
Efficient Fermentation

Abstract Background Itaconic acid is an unsaturated, dicarboxylic acid which finds a wide range of applications in the polymer industry and as a building block for fuels, solvents and pharmaceuticals. Currently, Aspergillus terreus is used for industrial production, with titers above 100 g L−1 depending on the conditions. Besides A. terreus, Ustilago maydis is also a promising itaconic acid production host due to its yeast-like morphology. Recent strain engineering efforts significantly increased the yield, titer and rate of production. Results In this study, itaconate production by U. maydis was further increased by integrated strain- and process engineering. Next-generation itaconate hyper-producing strains were generated using CRISPR/Cas9 and FLP/FRT genome editing tools for gene deletion, promoter replacement, and overexpression of genes. The handling and morphology of this engineered strain were improved by deletion of fuz7, which is part of a regulatory cascade that governs morphology and pathogenicity. These strain modifications enabled the development of an efficient fermentation process with in situ product crystallization with CaCO3. This integrated approach resulted in a maximum itaconate titer of 220 g L−1, with a total acid titer of 248 g L−1, which is a significant improvement compared to best published itaconate titers reached with U. maydis and with A. terreus. Conclusion In this study, itaconic acid production could be enhanced significantly by morphological- and metabolic engineering in combination with process development, yielding the highest titer reported with any microorganism.

scholarly journals Inactivation of pecS restores the virulence of mutants devoid of osmoregulated periplasmic glucans in the phytopathogenic bacterium Dickeya dadantii

Microbiology ◽  
2014 ◽  
Vol 160 (4) ◽  
pp. 766-777 ◽  
Author(s):  
Sébastien Bontemps-Gallo ◽  
Edwige Madec ◽  
Jean-Marie Lacroix
Keyword(s):  
Plant Cell Wall ◽  
Transcriptional Regulator ◽  
Soft Rot ◽  
Cellular Functions ◽  
Cell Wall Degrading Enzymes ◽  
Dickeya Dadantii ◽  
Phytopathogenic Bacterium ◽  
Wide Range ◽  
Severe Reduction ◽  
Rot Disease

Dickeya dadantii is a phytopathogenic enterobacterium that causes soft rot disease in a wide range of plant species. Maceration, an apparent symptom of the disease, is the result of the synthesis and secretion of a set of plant cell wall-degrading enzymes (PCWDEs), but many additional factors are required for full virulence. Among these, osmoregulated periplasmic glucans (OPGs) and the PecS transcriptional regulator are essential virulence factors. Several cellular functions are controlled by both OPGs and PecS. Strains devoid of OPGs display a pleiotropic phenotype including total loss of virulence, loss of motility and severe reduction in the synthesis of PCWDEs. PecS is one of the major regulators of virulence in D. dadantii, acting mainly as a repressor of various cellular functions including virulence, motility and synthesis of PCWDEs. The present study shows that inactivation of the pecS gene restored virulence in a D. dadantii strain devoid of OPGs, indicating that PecS cannot be de-repressed in strains devoid of OPGs.

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