scholarly journals Ethylene-Insensitive Tobacco Shows Differentially Altered Susceptibility to Different Pathogens

2003 ◽  
Vol 93 (7) ◽  
pp. 813-821 ◽  
Author(s):  
Bart P. J. Geraats ◽  
Peter A. H. M. Bakker ◽  
Christopher B. Lawrence ◽  
Enow A. Achuo ◽  
Monica Höfte ◽  
...  
Keyword(s):  
Erwinia Carotovora ◽  
Stem Rot ◽  
Potential Range ◽  
Symptom Development ◽  
Oidium Neolycopersici ◽  
Tobacco Plants ◽  
Necrotrophic Fungi ◽  
Total Peroxidase Activity ◽  
Ethylene Insensitivity ◽  
Increased Susceptibility

Transgenic tobacco plants (Tetr) expressing the mutant etr1-1 gene from Arabidopsis thaliana are insensitive to ethylene and develop symptoms of wilting and stem rot when grown in nonautoclaved soil. Several isolates of Fusarium, Thielaviopsis, and Pythium were recovered from stems of diseased Tetr plants. Inoculation with each of these isolates of 6-week-old plants growing in autoclaved soil caused disease in Tetr plants but not in nontransformed plants. Also, when 2-week-old seedlings were used, nontransformed tobacco appeared nonsusceptible to the Fusarium isolates, whereas Tetr seedlings did develop disease. Tetr seedlings were not susceptible to several nonhost Fusarium isolates. In contrast to results with Fusarium isolates, inoculation of 2-week-old seedlings with a Thielaviopsis isolate resulted in equal symptom development of nontransformed and Tetr tobacco. In order to explore the potential range of pathogens to which Tetr tobacco plants display enhanced susceptibility, the pathogenicity of several root and leaf pathogens was tested. Tetr plants were more susceptible to the necrotrophic fungi Botrytis cinerea and Cercospora nicotianae and the bacterium Erwinia carotovora, but only marginally more to the bacterium Ralstonia solanacearum. In contrast, the biotrophic fungus Oidium neolycopersici, the oomycete Peronospora tabacina, and Tobacco mosaic virus caused similar or less severe symptoms on Tetr plants than on nontransformed plants. Total peroxidase activity of Tetr plants was lower than that of nontransformed plants, suggesting a role for peroxidases in resistance against necrotrophic microorganisms. A comparable range of pathogens was examined on Arabidopsis and its ethylene-insensitive mutants etr1-1 and ein2-1. With the exception of one Fusarium isolate, ethylene insensitivity increased susceptibility of Arabidopsis plants to a similar spectrum of necrotizing pathogens as in tobacco. Thus, both ethylene-insensitive tobacco and Arabidopsis plants appear to be impaired in their resistance to necrotrophic pathogens.

scholarly journals Characterizing the Effect of Foliar Lipo-chitooligosaccharide Application on Sudden Death Syndrome and Sclerotinia Stem Rot in Soybean

2018 ◽  
Vol 19 (1) ◽  
pp. 46-53 ◽  
Author(s):  
David A. Marburger ◽  
Jaime F. Willbur ◽  
Maria E. Weber ◽  
Jean-Michel Ané ◽  
Medhi Kabbage ◽  
...  
Keyword(s):  
Sudden Death ◽  
Plant Root ◽  
Sudden Death Syndrome ◽  
Stem Rot ◽  
Signal Molecules ◽  
Symptom Development ◽  
Sclerotinia Stem Rot ◽  
Water Control ◽  
Fusarium Virguliforme ◽  
Glycine Max L

Lipo-chitooligosaccharides (LCOs) are signal molecules produced by plant root endosymbionts and have been identified, formulated, and marketed as growth-promoting adjuvants for soybean (Glycine max [L.] Merr.). Experiments were conducted under controlled environmental conditions to characterize the effects of foliar LCO applications on early symptom development of sudden death syndrome (SDS), caused by Fusarium virguliforme, and Sclerotinia stem rot (SSR), caused by Sclerotinia sclerotiorum. Treatment factors for the SDS experiment included two soybean cultivars (Sloan and CH2105R2), two inoculation levels (noninoculated control and inoculated), and two LCO applications (control and foliar LCO application), whereas two experimental soybean lines (91-38 and 91-44) and two LCO applications (water control and foliar LCO application) were used in the SSR experiment. The LCO application did not significantly influence SDS root symptom severity or early-season growth characteristics. However, on the susceptible line (P = 0.01) and with LCO application (P = 0.03), significantly larger SSR lesions developed compared with the nontreated control and resistant line. These results suggest foliar-applied LCOs have a limited effect on early root symptom development caused by F. virguliforme but increase stem symptom development caused by S. sclerotiorum.

scholarly journals Novel Quorum-Sensing-Controlled Genes in Erwinia carotovora subsp. carotovora: Identification of a Fungal Elicitor Homologue in a Soft-Rotting Bacterium

2005 ◽  
Vol 18 (4) ◽  
pp. 343-353 ◽  
Author(s):  
C. L. Pemberton ◽  
N. A. Whitehead ◽  
M. Sebaihia ◽  
K. S. Bell ◽  
L. J. Hyman ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Fusarium Oxysporum ◽  
Erwinia Carotovora ◽  
Homoserine Lactone ◽  
Stem Rot ◽  
Potato Tubers ◽  
Global Regulator ◽  
Signal Molecule ◽  
New Genes ◽  
Dicotyledonous Plants

Seven new genes controlled by the quorum-sensing signal molecule N-(3-oxohexanoyl)-L-homoserine lactone (OHHL) have been identified in Erwinia carotovora subsp. carotovora. Using TnphoA as a mutagen, we enriched for mutants defective in proteins that could play a role in the interaction between E. carotovora subsp. carotovora and its plant hosts, and identified NipEcc and its counterpart in E. carotovora subsp. atroseptica. These are members of a growing family of proteins related to Nep1 from Fusarium oxysporum which can induce necrotic responses in a variety of dicotyledonous plants. NipEcc produced necrosis in tobacco, NipEca affected potato stem rot, and both affected virulence in potato tubers. In E. carotovora subsp. carotovora, nip was shown to be subject to weak repression by the LuxR family regulator, EccR, and may be regulated by the negative global regulator RsmA.

scholarly journals First Report of Erwinia carotovora subsp. carotovora Causing Bacterial Root Rot of Sweetpotato (Ipomoea batatas) in Louisiana

Plant Disease ◽  
1998 ◽  
Vol 82 (1) ◽  
pp. 129-129 ◽  
Author(s):  
C. A. Clark ◽  
M. W. Hoy ◽  
J. P. Bond ◽  
C. Chen ◽  
Y.-K. Goh ◽  
...  
Keyword(s):  
Root Rot ◽  
Ipomoea Batatas ◽  
Disease Incidence ◽  
Erwinia Carotovora ◽  
Soft Rot ◽  
Stem Rot ◽  
Identification System ◽  
Natural Occurrence ◽  
Storage Roots ◽  
First Report

Bacterial root and stem rot of sweetpotato (Ipomoea batatas (L.) Lam.) was first fully characterized in the U.S. in 1977 (2). It was thought to be caused exclusively by Erwinia chrysanthemi. Although a previous report described sweetpotato as a host for E. carotovora subsp. carotovora, based on artificial inoculations, others have reported that neither E. carotovora subsp. carotovora nor E. carotovora subsp. atroseptica decay sweetpotato storage roots (1). In October 1995, storage roots of sweetpotato cv. Beauregard were received from St. Landry Parish, LA, that displayed typical bacterial root rot. Isolations from these roots yielded bacteria that showed a similarity of 0.945 to E. carotovora subsp. carotovora with the Biolog GN Bacterial Identification System (version 3.50). This isolate (Ecc-LH) also differed from isolates of E. chrysanthemi (Ech) from sweetpotato and other hosts in that it was insensitive to erythromycin, did not produce phosphatase or lecithinase, and did not produce gas from glucose. Ecc-LH differed from known strains of E. carotovora subsp. atroseptica in that it did not produce reducing substances from sucrose or acid from palatinose. When Beauregard storage roots were inoculated by inserting micropipette tips containing 50 μl of 1.0 × 108 CFU/ml, both Ecc-LH and Ech-48 produced typical bacterial root rot symptoms. However, when they were compared by infectivity titrations at 28 to 32°C, Ecc-LH was less virulent than Ech-48. Ecc-LH had an ED50 of approximately 1.0 × 106 CFU/ml and did not cause appreciable disease below inoculum concentrations of 1.0 × 105, whereas Ech-48 had an ED50 of approximately 1.0 × 108 and caused soft rot at the lowest concentration tested, 1.0 × 103. Similar disease incidence was observed in infectivity titrations at 22 to 24°C, but Ech-48 caused less severe soft rot. E. carotovora subsp. carotovora was reisolated from inoculated storage roots and its identity was reconfirmed by Biolog. When terminal vine cuttings of Beauregard were dipped in 1.0 × 108 CFU/ml and planted in a greenhouse, bacterial stem rot symptoms developed on plants inoculated with Ech-48 at about 4 weeks postinoculation, or when new growth began. However, no symptoms developed on plants inoculated with Ecc-LH. This is the first report of natural occurrence of E. carotovora subsp. carotovora causing bacterial root rot of sweetpotato in Louisiana. E. chrysanthemi remains the most important pathogen causing bacterial soft rot in sweetpotato since it is widely associated with sweetpotato, is more virulent on storage roots and also causes a stem rot. E. carotovora subsp. carotovora can cause root rot, but has been isolated in only one location to date, is less virulent on storage roots, and apparently does not cause stem rot on the predominant cultivar in U.S. sweetpotato production, Beauregard. References: (1) C. A. Clark and J. W. Moyer. 1988. Compendium of Sweet Potato Diseases. American Phytopathological Society, St. Paul, MN. (2) N. W. Schaad and D. Brenner. Phytopathology 67:302, 1977.

PREDISPOSITION OF TOBACCO TO OZONE DAMAGE

1965 ◽  
Vol 45 (1) ◽  
pp. 1-12 ◽  
Author(s):  
F. D. H. Macdowall
Keyword(s):  
Protein Content ◽  
Small Dose ◽  
Stomatal Opening ◽  
Low Doses ◽  
Long Term Effects ◽  
Night Temperature ◽  
Tobacco Plants ◽  
Moisture Supply ◽  
Increased Susceptibility

Effects of ontogeny, genome, nitrogen, and water supplies and ozone itself in predisposing tobacco plants to ozone damage (including weather fleck) are described from experiments in both field and greenhouse. The fully expanded leaf became susceptible to low doses of ozone at the time its protein content started to fall. Topping slowed the development of susceptibility of leaves, with the result that the susceptibility of the plants was decreased. Effects of genome were at least partly of an ontogenetic nature. Susceptibility was enhanced by both deficiency and excess of nitrogen. Moisture prior to fumigation increased susceptibility. Long term effects of moisture supply were akin to its influence on drought-hardiness. Susceptibility was increased by shortened photoperiod, low day temperature, and high night temperature, indicating a protective influence of photosynthat. A large or a small dose of ozone appeared to predispose against or toward, respectively; susceptibility to the next dose. Wherever tested, stomatal opening was positively associated with damage. Since stomatal opening regulates the flux of ozone into the leaf, it controls the amount of damage to tissue of a given degree of susceptibility.

scholarly journals Transgenic tobacco plants expressing antisense ferredoxin-NADP(H) reductase transcripts display increased susceptibility to photo-oxidative damage

2003 ◽  
Vol 35 (3) ◽  
pp. 332-341 ◽  
Author(s):  
Javier F. Palatnik ◽  
Vanesa B. Tognetti ◽  
Hugo O. Poli ◽  
Ramiro E. Rodríguez ◽  
Nicolás Blanco ◽  
...  
Keyword(s):  
Oxidative Damage ◽  
Transgenic Tobacco ◽  
Transgenic Tobacco Plants ◽  
Tobacco Plants ◽  
Increased Susceptibility

scholarly journals An Outbreak of Bacterial Stem Rot of Dieffenbachia amoena Caused by Erwinia carotovora subsp. carotovora in the Eastern Mediterranean Region of Turkey

Plant Disease ◽  
2004 ◽  
Vol 88 (3) ◽  
pp. 310-310 ◽  
Author(s):  
R. Cetinkaya-Yildiz ◽  
M. Mirik ◽  
Y. Aysan ◽  
M. Kusek ◽  
F. Sahin
Keyword(s):  
Mediterranean Region ◽  
Eastern Mediterranean ◽  
Disease Incidence ◽  
Eastern Mediterranean Region ◽  
Acid Methyl Ester ◽  
Erwinia Carotovora ◽  
Soft Rot ◽  
Stem Rot ◽  
Tomato Plants ◽  
Rot Disease

Severe outbreaks of bacterial stem rot disease occurred on dieffenbachia plants (Dieffenbachia amoena cv. Tropic Snow) during the autumn and spring seasons of 2002 and 2003 in two commercial glasshouses (3.5 ha) near Adana and Mersin in the Eastern Mediterranean Region of Turkey. Characteristic symptoms of the disease were wilting of the lower leaves, darkening and water soaking of the leaves and stem at or below the soil level, and browning in the vessel and pith of the diseased plants. Eventually, the stem and leaves completely rotted, and the plants collapsed. Nearly 30 and 40% (2002 and 2003, respectively) of the 20,000 potted plants in the glasshouses were destroyed because of the disease. Cuttings often developed a typical soft rot during propagation. Disease incidence was estimated at approximately 50% on propagating material during 2003. Isolations were made from rotted stems, leaves, and discolored vessels of the dieffenbachia plants on King's medium B. Bacteria consistently isolated from the diseased tissues formed white-to-cream colonies on the medium. Bacteria from purified colonies were gram, oxidase, and arginine dyhidrolase negative, catalase positive, and facultative anaerobic. Ten representative strains all fermented glucose and reduced nitrates to nitrites. The strains caused soft rot of potato slices within 24 h at 25°C. All strains were resistant to erythromycin in an antibiotic disk (15 μg) assay. Negative results were obtained from utilization of α-methyl glycoside, reducing substance from sucrose, and indole production from tryptophane and phosphathase activity. Positive results were obtained from pectate, aesculin, and gelatine liquefaction for all strains. Acid was produced from glucose, sucrose, mannitol, mannose, lactose, raffinose, melibiose, trehalose, and L(+)-arabinose but not Darabinose, sorbitol, inulin, and maltose. Pathogenicity was confirmed by needle-stab inoculation at the stem on three plants each of dieffenbachia and tomato plants (5-week-old cv. H-2274). Sterile distilled water was used as a negative control. All plants were covered with polyethylene bags for 48 h at 25°C. Within 72 h after inoculation, water-soaking and soft-rot symptoms were observed on dieffenbachia and tomato plants. All of the bacterial strains isolated in the present study were identified as Erwinia carotovora subsp. carotovora (Jones) based on fatty acid methyl ester analysis with similarity indices ranging from 80 to 94%. Furthermore, Biolog GN (Department of Plant Protection, Faculty of Agriculture, Ataturk University, Erzurum, Turkey) profiles identified them as the same pathovar with similarity values of 67 to 72%. All of the test results were similar to those of reference strain GSPB 435 (Gottinger Sammlung phytopathogener Bakterien, Georg-August University, Gottingen, Germany) of E. carotovora subsp. carotovora used in this study. To our knowledge, this is the first report of the occurrence and outbreak of a bacterial rot disease on dieffenbachia grown in the Eastern Mediterranean Region of Turkey. Contaminated cuttings may be the primary source of inoculum within and between glasshouses.

DNA based detection of blackleg and soft rot disease causing Erwinia strains in seed potatoes

2006 ◽  
pp. 1-6
Author(s):  
Yeshitila Degefu ◽  
Sanna Jokela ◽  
Erkki Joki-Tokola ◽  
Elina Virtanen
Keyword(s):  
Crop Residues ◽  
Enrichment Culture ◽  
Seed Tuber ◽  
Erwinia Carotovora ◽  
Soft Rot ◽  
Stem Rot ◽  
Current Status ◽  
Future Research ◽  
Aerial Stem ◽  
Different Strains

Erwinia carotovora subsp. atroseptica (Eca), Erwinia carotovora subsp. carotovora (Ecc) and Erwinia chrysanthemi (Ech) are the different sub species of Erwinia that cause the diseases commonly known as blackleg, aerial stem rot and soft rot on potato. Blackleg and aerial stem rot affect vines during the growing season, whereas soft rot affects tubers in the field and during transit and storage. The three species can cause soft rot under cool and moist conditions. E. carotovora subsp. atroseptica is the major cause of blackleg, a blackening of the stem base of potato plants, which originates from the mother tuber (Pérombelon and Kelman, 1987). Erwinia carotovora subsp. carotovora mainly causes aerial stem rot (aerial blackleg), but under high temperatures it has been reported to cause blackleg like symptoms. E. chrysanthemi also induces blackleg-like symptoms. Until recently E. chrysanthemi had been mainly confined to warmer climates of Europe, Australia and the tropics. To date the species has been known to occur in cool temperate regions including Finland. In Finland E. chrysanthemi the strain has been reported for the first time in 2004 and it appears to spread fast in certain parts of country (Degefu, unpublished, Pirhonen, personal communication). Although infested crop residues and rotting tubers are among the important sources of inoculum, latent infections in seed tuber provide the major source of infection in potato production (Hannukkala and Segertedt, 2004). At the seed potato laboratory MTT, Ruukki we are carrying out research and services on PCR (DNA) based detection of latent infection of blackleg and soft rot Erwinia strains. The enrichment of the bacteria in semi selective liquid medium prior to PCR ( BIO-PCR) is an important initial step for the success in PCR detection extremely low number of the target bacteria from tubers. The different strains appear to differ in their ability to compete with other saprophytes and reach the target detection limit of bacterial population during the enrichment culture of the potato peel extract. Results of prior PCR enrichment of the bacteria, detection limits of the different strains and preliminary data, from the analysis of some seed lots from the high grade area of north Ostrobothnia and Åland regions, on the occurrence of the strains and the new trends of introduction and spread of E. chrysanthemi in Finland are presented and discussed. Evaluation of the current status of Erwinia diagnostics and areas of future research are highlighted

scholarly journals Stem Rot of Branched Broomrape (Orobanche ramosa) Caused by Sclerotium rolfsii in Chile

Plant Disease ◽  
2010 ◽  
Vol 94 (10) ◽  
pp. 1266-1266 ◽  
Author(s):  
R. Galdames ◽  
J. Diaz
Keyword(s):  
Ribosomal Rna ◽  
Biological Control Agent ◽  
Direct Sequencing ◽  
Sclerotium Rolfsii ◽  
Central Zone ◽  
Stem Rot ◽  
Its2 Region ◽  
Rrna Gene ◽  
Fungal Culture ◽  
Tobacco Plants

Branched broomrape is a holoparasitic weed present in some areas of central and southern Chile (33°S to 38°S), which is often found parasitizing tomato and tobacco crops. During an extensive survey conducted in different tomato-growing areas during the summer of 2010, branched broomrape plants with stem rot symptoms were detected in a commercial tomato crop located in the central zone (34°14′S, 71°1′W). Rotten stems were observed with white mycelia and approximately 1-mm-diameter spherical sclerotia on affected tissue below the soil surface. Parasitized tomato plants showed no symptoms. Sclerotia were taken directly from affected stems with a dissecting needle under a stereoscopic microscope in a flow chamber and placed on potato dextrose agar (PDA) medium. Germinating sclerotia consistently produced colonies similar to Sclerotium rolfsii with new sclerotia formed within 6 to 7 days. Mycelia produced hyphal clamp connections under the light microscope (2). DNA was extracted from one fungal culture. The ITS1 region, 5.8S rRNA gene, and the ITS2 region of the nuclear-encoded ribosomal RNA gene were amplified with primers ITS1 and ITS4 (4). The sequence was deposited in GenBank (Accession No. HM222638) and showed ≥99% identity values with sequences of similar regions from Athelia rolfsii (anamorph S. rolfsii; Accession Nos. AB075304, DQ0595578, AF499018, and AB075305). Different pathogenicity tests were performed. Inoculum was prepared by placing mycelia plugs from a PDA-grown, 6-day-old colony in a flask with sterilized wheat seeds and incubated for 2 weeks. Three Orobanche plants, each one with 10 to 15 shoots at different aerial stages (starting emergence, flowering, and formed capsules) were gently planted separately in 35-cm pots. Inoculum (10 g per pot) was placed in the soil surrounding the plants. One pot was used as a control. Forty-five-day-old tomato and tobacco plants were additionally inoculated by a similar procedure. After 12 days, inoculated Orobanche plants showed reduced vigor and stem decay. After 9 days, tomato and tobacco plants showed wilt. In all cases, the fungus was reisolated on PDA from all inoculated plants. To our knowledge, this is the first report of S. rolfsii on O. ramosa (1). A previous report of S. rolfsii parasitizing O. cernua has also been made (3). The high susceptibility of tomato and tobacco plants to this isolate of S. rolfsii precludes the use of this pathogen as a biological control agent against broomrape. References: (1) D. F. Farr and A. Y. Rossman. Fungal Databases. Systematic Mycology and Microbiology Laboratory, ARS, USDA. Retrieved May 14, 2010, from http://nt.ars-grin.gov/fungaldatabases . (2) Z. K. Punja and A. Damiani. Mycologia 88:694, 1996. (3) C. A. Raju et al. Phytoparasitica 23:235, 1995. (4) T. J. White et al. Amplification and direct sequencing of fungal ribosomal RNA genes for phylogenetics. Page 315 in: PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, New York, 1990.

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