Accumulation of mansonones in callus cultures of Ulmus americana L. in the absence of a fungal-derived elicitor

1997 ◽  
Vol 75 (3) ◽  
pp. 513-517 ◽  
Author(s):  
F. G. Meier ◽  
W. R. Remphrey
Keyword(s):  
Culture Media ◽  
Fungal Growth ◽  
Callus Cultures ◽  
Dutch Elm Disease ◽  
Ulmus Americana ◽  
Ophiostoma Ulmi ◽  
Medium Components ◽  
Tissue Culture Media ◽  
Wound Reaction ◽  
Accumulation Ability

The Dutch elm disease pathogens Ophiostoma ulmi (Buism.) Nannf. and Ophiostoma novo-ulmi Brasier elicit the production of phytoalexins called mansonones in the American elm (Ulmus americana L.). As part of a larger investigation, it was revealed that mansonone elicitation in callus culture does not require the Dutch elm disease pathogens, as has been reported in other studies. The objective of this study was to determine the nature and timing of the nonfungal elicited mansonone accumulation in U. americana callus. Initially, 7-week-old calli were subjected to inoculations with various fungal growth medium components. Mansonone production occurred in all treatments, indicating that it was stimulated prior to the addition of the medium components. Next, cotyledons and calli at various stages of development were analysed for the production of mansonones to determine the timing of its production. Mansonone production appeared to be correlated with the initiation of callus production and may be related to the callus wound reaction. As the callus aged, its colour changed from white–green to brown possibly as a result of phytoalexin accumulation. Additional experiments in which the cotyledon source, agar source, and type of plant tissue culture media were modified resulted in no change to the mansonone accumulation ability of the callus. The discrepancy between our results and those of other researchers could be due to differences in the method of mansonone quantification, namely, that our method is more sensitive and led to the detection of mansonones where previously none had been found. Further research must be done in this area to investigate this mansonone accumulation. Key words: phytoalexin, Dutch elm disease, mansonone, Ulmus americana, callus.

scholarly journals Effect of Elm Selection, Explant Source and Medium Composition on Growth of Ophiostoma ulmi on Callus Cultures

1992 ◽  
Vol 10 (1) ◽  
pp. 59-62
Author(s):  
Subhash C. Domir ◽  
Lawrence R. Schreiber ◽  
Jann M. Ichida ◽  
Steven M. Eshita
Keyword(s):  
Growth Rate ◽  
High Performance ◽  
Callus Tissue ◽  
Fungal Growth ◽  
Callus Cultures ◽  
Medium Composition ◽  
Dutch Elm Disease ◽  
Ophiostoma Ulmi ◽  
American Elm ◽  
Explant Source

Abstract We examined the effects of elm selection, explant source and media composition on growth of the Dutch elm disease (DED) fungus Ophiostoma ulmi on callus cultures. Calluses were generated from leaf and stem tissue of an American elm (Ulmus Americana L.) seedling (A), susceptible to the disease; an American elm selection 8630, resistant to the disease; and a Siberian elm (U. pumila L.) seedling, also resistant to DED. Calluses were generated on modified Murashige-Skoog (MMS) medium, either with (MMSC) or without coconut milk. Explant source did not affect the fungal growth rate on the callus. Rate of O. ulmi growth on American elm A callus was similar on both media; on Siberian and 8630, fungal growth rate was more rapid on callus cultured on MMS than on MMSC. However, in the absence of callus tissue, O. ulmi growth on MMSC medium was more than five times as rapid as it was on MMS. We observed significant interactions between explant source and selection, and between medium and selection. Fungal growth was always more rapid on American A, and American 8630 then on Siberian. Scanning electron microscopy revealed heavy fungal sporulation on American A, slight on Siberian and none on American 8630. High performance liquid chromatography analysis showed that the secondary metabolic profiles were distinguishable for callus tissue versus explant tissue, but were similar for calli generated from different explant sources.

Eliminating Thrips in Microshoot Cultures

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 506d-506
Author(s):  
Robert R. Tripepi ◽  
Holly J. Schwager ◽  
Mary W. George ◽  
Joseph P. McCaffrey
Keyword(s):  
Betula Pendula ◽  
Culture Media ◽  
Dry Weight ◽  
Thrips Tabaci ◽  
Shoot Cultures ◽  
Onion Thrips ◽  
Ulmus Americana ◽  
Shoot Height ◽  
Tissue Culture Media ◽  
Plant Tissue Cultures

Two insecticides, acephate or azadirachtin, were added to tissue culture media to determine their effectiveness in controlling onion thrips (Thrips tabaci Lindeman.) and to determine if these insecticides could damage the plant shoot cultures. To test for insecticide phytotoxicity, microshoots from European birch (Betula pendula), American elm (Ulmus americana), `Pink Arola' chrysanthemum (Dendranthema grandiflora), `America' rhododendron (Rhododendron catawbiense), `Golden Emblem' rose (Rosa hybrida), and `Gala' apple (Malus domestica) were placed in 130-ml baby food jars containing 25 ml of medium supplemented with 6.5, 13, or 26 mg/l Orthene® (contained acephate) or 0.55, 1.1, or 2.2 ml/l Azatin® (contained azadirachtin). Control jars lacked insecticide. To test for thrips control, 13 mg/l Orthene® or 0.55 ml/l Azatin® was added to Murashige and Skoog medium, and 10 thrips were placed on `Gala' apple microshoots in each jar. Jars were sealed with plastic wrap. In both studies, microshoot dry weight and heights were determined. In the second study, the total number of thrips per jar was also determined 3 weeks after inoculation. Microshoots on Orthene®-treated media lacked phytotoxicity symptoms, regardless of the concentration used. In contrast, Azatin® hindered plant growth, decreasing shoot height or dry weight by up to 85% depending on the species. Both insecticides prevented thrips populations from increasing, since less than 10 thrips were found in jars with insecticide-treated medium. Control jars, however, contained an average of almost 70 thrips per jar. This study demonstrated that both Orthene® and Azatin® were effective for eradicating thrips from plant tissue cultures, but Orthene® should probably be used because Azatin® was phytotoxic to all species tested.

Barrier zone formation in host and nonhost trees inoculated with Ophiostoma ulmi. I. Anatomy and histochemistry

1991 ◽  
Vol 69 (9) ◽  
pp. 2055-2073 ◽  
Author(s):  
Danny Rioux ◽  
G. B. Ouellette
Keyword(s):  
Principal Component ◽  
Dutch Elm Disease ◽  
Populus Balsamifera ◽  
Ulmus Americana ◽  
Zone Formation ◽  
Ophiostoma Ulmi ◽  
Parenchyma Cells ◽  
Zone Cell ◽  
Histochemical Tests ◽  
Barrier Zone

Barrier zone formation was studied in small branches of Ulmus americana L., Prunus pensylvanica L.f., and Populus balsamifera L. following inoculation with Ophiostoma ulmi (Buism.) Nannf. (the Dutch elm disease pathogen). Barrier zones were continuous in the nonhosts whereas they were generally discontinuous in U. americana; barrier zone formation also occurred at a later stage of infection in the latter than in the former. Barrier zones were formed of parenchyma cells and fibers in U. americana, mainly of parenchyma cells in Prunus pensylvanica, and of fibers in Populus balsamifera. Fibers as a principal component of barrier zones are described for the first time. Histochemical tests revealed that the proportion of lignin was higher in barrier zone cell walls than in elements of the noninvaded xylem. Barrier zones contained suberized cells, the number of which was progressively greater in the order U. americana, Prunus pensylvanica, and Populus balsamifera. However, many fibers of U. americana occasionally formed a continuous barrier zone and had an internal layer that was slightly suberized. In addition, phenolic compounds were usually detected within barrier zone cells of these species. Key words: Dutch elm disease, nonhost plants, Ophiostoma ulmi, Ulmus americana, anatomy, histochemistry.

scholarly journals Identification and Control of Bacterial Contamination in Callus Cultures of Ulmus americana

1996 ◽  
Vol 14 (2) ◽  
pp. 50-52
Author(s):  
Lawrence R. Schreiber ◽  
Subhash C. Domir ◽  
V.M. Gingas
Keyword(s):  
Culture Media ◽  
Leaf Tissue ◽  
Callus Cultures ◽  
Airborne Spores ◽  
Ulmus Americana ◽  
Bacillus Macerans ◽  
Burner Flame ◽  
Ethanol Ethanol ◽  
And Control ◽  
Latent Bacteria

Abstract Bacillus macerans Schardinger appeared on culture media and forceps used in serial transfers of Ulmus americana callus tissue after several contamination-free transfers and may have originated as an endophyte in the leaf tissue used as an explant. Bacteria remained viable on forceps stored for several weeks in 95% ethanol whether or not the excess was burned off in a flame from an alcohol lamp. Bacteria were eliminated from forceps treated similarily with 85% ethanol. The bacterium on artificially contaminated forceps remained viable after immersion up to 4 hr in either 95%, 85%, 80%, or 70% ethanol with or without flaming. Artificial contamination was eliminated, either by autoclaving for 20 min at 121C (185.8F) or exposure to a bunsen burner flame for 6-8 sec. Bacillus macerans remained viable in both naturally and artificially contaminated ethanol at dilutions of 95%, 85%, 80%, and 70%. Thus, forceps may be contaminated by latent bacteria in callus or contaminated ethanol. Ethanol may become contaminated by storage of nonsterile forceps and airborne spores introduced during routine, septic procedures.

scholarly journals Variation in Response of Selected American Elm Clones to Ophiostoma ulmi

1995 ◽  
Vol 13 (3) ◽  
pp. 126-128 ◽  
Author(s):  
A.M. Townsend ◽  
S.E. Bentz ◽  
G.R. Johnson
Keyword(s):  
Dutch Elm Disease ◽  
Main Trunk ◽  
Ulmus Americana ◽  
Disease Symptoms ◽  
Ophiostoma Ulmi ◽  
American Elm ◽  
Causal Fungus ◽  
One Year ◽  
Crown Dieback ◽  
High Degree

Abstract Ramets of nine American elm (Ulmus americana L.) clones or cultivars were planted with ramets of Ulmus ‘Frontier’, Ulmus ‘Prospector’, and American elm seedlings in a randomized block, split-plot design. When they were three years old, the trees were inoculated in the main trunk on either one of two selected dates in May with a spore suspension of Ophiostoma ulmi, the causal fungus for Dutch elm disease (DED). Analyses of variance showed significant variation among clones and between inoculation dates in disease symptoms four weeks and one year after inoculation. Inoculations made on May 18 generally created significantly more symptoms than inoculations made only nine days later. Four-week symptom expression was influenced also by a significant interaction between clonal or seedling group and inoculation date. When data from both inoculation dates were combined, six American elm clones (‘American Liberty’, ‘Princeton’, 680, R18–2, 180, and 3) showed significantly fewer foliar symptoms after four weeks than the American elm seedlings and three other American elm clones. Five of these same six more tolerant American clones averaged significantly less crown dieback after one year than the other American clones or seedlings tested. One of the American elm clones (clone 3) showed a level of disease tolerance equal statistically to ‘Frontier’ and ‘Prospector’, two cultivars which have shown a high degree of tolerance to DED in other studies.

scholarly journals A Comparison between Synthetic and Organic Iron Chelators on in Vitro Growth of Nicotiana tabacum Callus Cultures

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 630g-631
Author(s):  
Lisa C. Berg ◽  
Henry R. Owen
Keyword(s):  
Nicotiana Tabacum ◽  
Culture Media ◽  
Basal Medium ◽  
Callus Cultures ◽  
Callus Growth ◽  
Fresh Weight ◽  
Iron Chelate ◽  
Tissue Culture Media ◽  
The Media

Nicotiana tabacum callus growth (fresh weight) was measured after culture in the light (16-hour photoperiod) or in darkness for four different culture media, differing in iron chelate type or concentration. All media contained MS basal medium supplemented with 30 g·L–1 sucrose, 2 mg·L–1 IAA, 0.2 mg·L–1 KIN, and 7 g·L–1 agar, pH 5.8. Three of the media contained iron-metalosate (Albion Laboratories), an organic iron chelate, at 100, 200, and 400 micromolar concentrations, and the fourth medium contained 100 μm Fe-EDTA. Twenty-five culture tubes were prepared for each of the 4 different media concentrations and 2 light treatments (8 treatments total). A 1-cm3 callus explant was used for each treatment and cultured for 56 days at 20°C. About 20-fold increases in callus fresh weight were observed for cultures incubated in light or in darkness. In addition, callus growth was not significantly affected by iron chelate type, suggesting the potential utility of this organic chelator in tissue culture media to alleviate potential problems of light-induced EDTA instability and subsequent IAA inactivation. These cultures are being maintained to examine the influence of iron chelate type on organogenesis.

Factors Affecting Growth of Ophiostoma ulmi on Elm Callus Tissue

1991 ◽  
Vol 9 (4) ◽  
pp. 211-215
Author(s):  
Subhash C. Domir ◽  
Lawrence R. Schreiber ◽  
Jann M. Ichida
Keyword(s):  
Significant Interaction ◽  
Callus Tissue ◽  
Fungal Growth ◽  
Dutch Elm Disease ◽  
Inoculum Concentration ◽  
Ophiostoma Ulmi ◽  
Factors Affecting ◽  
American Elm ◽  
Intermediate Resistance

Abstract We examined growth of the Dutch elm disease fungus, Ophiostoma ulmi, on callus derived from a susceptible American elm (Ulmus amencana, selection A), an American elm of intermediate resistance (U. americana, selection 8630), and a resistant Siberian elm (Ulmus pumlia) at 16, 22, and 28°C (61,72, and 83°F) and inoculation concentrations of 15 × 106, 2 × 106, or 0.3 × 106 conidia/ml. After 72 hours, the rates of fungal growth for all treatments were most rapid on calli from the American 8630 selection followed by the American A and Sibenan selections. While fungal growth was more rapid over American 8630, it was more dense on American A. Most rapid fungal growth occurred at 22°C (72°F) and was directly proportional to the inoculum concentration. A significant interaction was noted between callus source and temperature.

EVALUATION OF MONOSODIUM METHANE ARSENATE FOR THE SUPPRESSION OF NATIVE ELM BARK BEETLES, HYLURGOPINUS RUFIPES (EICHHOFF) (COLEOPTERA: SCOLYTIDAE)

1996 ◽  
Vol 128 (3) ◽  
pp. 435-441 ◽  
Author(s):  
I.L. Pines ◽  
A.R. Westwood
Keyword(s):  
Bark Beetles ◽  
Management Program ◽  
Dutch Elm Disease ◽  
Egg Hatch ◽  
Ulmus Americana ◽  
Ophiostoma Ulmi ◽  
Elm Bark Beetle ◽  
Hylurgopinus Rufipes ◽  
And Control ◽  
Elm Bark Beetles

AbstractThe native elm bark beetle, Hylurgopinus rufipes (Eichhoff), is the major vector of Dutch elm disease, Ophiostoma ulmi (Buisman) Nannf., in Manitoba. The herbicide Glowon™, monosodium methane arsenate (MSMA), was applied to a chainsaw cut in American elm, Ulmus americana L., tree stems to determine if the treated elms would become effective trap trees for H. rufipes. Three treatments were compared: treated with herbicide and girdled, girdled, and control. All herbicide-treated elms died within 18 days after application. Significantly higher numbers (P < 0.01) of native elm bark beetles were attracted to the herbicided elms, compared with the other treatments. Beetles bred only in the elms treated with herbicide. Of the total brood galleries constructed, 72% had no egg hatch while the remaining 28% had larval tunnels. Progeny adults emerged from less than 1% of the larval tunnels. MSMA application could supplement the Dutch elm disease management program in Manitoba.

scholarly journals Fungal Colonization and Host Defense Reactions in Ulmus americana Callus Cultures Inoculated with Ophiostoma novo-ulmi

2009 ◽  
Vol 99 (6) ◽  
pp. 642-650 ◽  
Author(s):  
Mirella Aoun ◽  
Danny Rioux ◽  
Marie Simard ◽  
Louis Bernier
Keyword(s):  
Electron Microscopy ◽  
Quantitative Polymerase Chain Reaction ◽  
Callus Cultures ◽  
Dutch Elm Disease ◽  
Fungal Colonization ◽  
Ulmus Americana ◽  
In Vitro System ◽  
Transmission Electron ◽  
Callus Tissues

The host–pathogen interaction leading to Dutch elm disease was analyzed using histo- and cyto-chemical tests in an in vitro system. Friable and hard susceptible Ulmus americana callus cultures were inoculated with the highly aggressive pathogen Ophiostoma novo-ulmi. Inoculated callus tissues were compared with water-treated callus tissues and studied with light microscopy (LM), transmission-electron microscopy (TEM), and scanning-electron microscopy (SEM). New aspects of this interaction are described. These include the histological observation, for the first time in plant callus cultures, of suberin with its typical lamellar structure in TEM and the intracellular presence of O. novo-ulmi. Expression of the phenylalanine ammonia lyase gene, monitored by real-time quantitative polymerase chain reaction, was correlated with the accumulation of suberin, phenols, and lignin in infected callus cultures. This study validates the potential use of the in vitro system for genomic analyses aimed at identifying genes expressed during the interaction in the Dutch elm disease pathosystem.

Nonsporulation in the Dutch elm disease fungus Ophiostoma ulmi: evidence for control by a single nuclear gene

1994 ◽  
Vol 72 (4) ◽  
pp. 461-467 ◽  
Author(s):  
Wayne C. Richards
Keyword(s):  
Key Words ◽  
Genetic Control ◽  
Genetic Stability ◽  
Nuclear Gene ◽  
Dutch Elm Disease ◽  
Wild Type ◽  
Ulmus Americana ◽  
Disease Symptoms ◽  
Ophiostoma Ulmi ◽  
Yeast Phase

A single nuclear gene controls nonsporulation in a novel isolate of the Dutch elm disease fungus Ophiostoma ulmi (Buism.) Nannf. This has been clearly demonstrated through segregation of the nonsporulating phenotype-in meiotic products recovered from crosses between a mutant nonsporulating isolate (WRB2-1) and wild-type sporulating isolates, between F1 progeny and their parents, and between F1 progeny. All crosses between nonsporulating and sporulating isolates yielded a 1:1 ratio for these two phenotypes in the meiotic products, whereas all crossings between isolates of the same phenotype produced meiotic products of that phenotype. The genetic stability of the nonsporulating phenotype was clearly shown when no disease symptoms were observed following artificial inoculation of the nonsporulating progeny into white elm, Ulmus americana L. Exposure to trifluoperazine, a calmodulin inhibitor, did not shift the nonsporulating isolates to the yeast phase, which supports our findings that nonsporulation is under genetic control rather than metabolic control. Key words: nonsporulation, Ophiostoma ulmi, mutant, single nuclear gene, meiotic products.

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