Verticillium wilt of chrysanthemum: suppression of fungal colonization of leaves and prevention of wilt symptom development by foliar applications of benomyl

1971 ◽  
Vol 49 (11) ◽  
pp. 1987-1991 ◽  
Author(s):  
Lloyd V. Busch ◽  
Robert Hall
Keyword(s):  
Verticillium Wilt ◽  
Fungal Growth ◽  
Tween 20 ◽  
Fungal Colonization ◽  
Systemic Fungicide ◽  
Symptom Expression ◽  
Symptom Development ◽  
Fungal Activity ◽  
Single Leaf ◽  
Wilt Symptom

This report describes the use of a systemic fungicide in a study of the relation between fungal colonization of a plant and symptom expression. The systemic fungicide benomyl (methyl 1-(butylcarbamoyl)-2-benzimidazolecarbamate) was used to selectively suppress development of Verticillium dahliae in leaves of chrysanthemum plants infected via the roots.Benomyl sprayed or painted onto foliage at weekly intervals as a 20 mg/liter solution in 0.25% aqueous Tween 20 restricted development of V. dahliae in leaves and prevented wilt symptom development. Numbers of propagules of V. dahliae recovered from stems of symptomless benomyl-treated plants were similar to those recovered from stems of untreated inoculated plants expressing wilt symptoms. Material toxic to Verticillium was detected in leaves but not in stems of plants receiving foliar paint applications of benomyl. Benomyl applied repeatedly to a single leaf on an inoculated plant suppressed fungal growth and symptom development in that leaf while untreated leaves wilted and became necrotic in the usual way. The observations support the hypothesis that symptom expression in leaves of chrysanthemum plants infected with Verticillium is largely due to fungal activity within infected leaves rather than fungal activity in the roots or stem.

Verticillium wilt of chrysanthemum: colonization of leaves in relation to symptom development

1971 ◽  
Vol 49 (2) ◽  
pp. 181-185 ◽  
Author(s):  
R. Hall ◽  
L. V. Busch
Keyword(s):  
Verticillium Wilt ◽  
Significant Contribution ◽  
Vascular System ◽  
Symptom Expression ◽  
Rapid Rise ◽  
Symptom Development ◽  
Flower Buds ◽  
Advanced Stages ◽  
Wilt Symptom ◽  
Leaf Exudate

The vascular system of leaves of chrysanthemum plants inoculated with Verticillium dahliae was invaded by mycelium before the appearance of visible wilt symptoms. After flower buds appeared a rapid rise in the number of propagules of fungus in the leaf was followed by a rise in severity of visible wilt symptom expression and conductivity of leaf exudate. Those portions of the leaf with the most advanced stages of wilt contained the greatest amounts of fungus. It is suggested that the mycelium within the leaf makes a significant contribution to the development of symptoms of wilt.

Cyanogenic potential of Trifolium repens L. in relation to pepper spot caused by Stemphylium sarciniforme

1978 ◽  
Vol 56 (20) ◽  
pp. 2491-2496 ◽  
Author(s):  
H. T. Wilkinson ◽  
R. L. Millar
Keyword(s):  
White Clover ◽  
Trifolium Repens ◽  
Fungal Colonization ◽  
Symptom Expression ◽  
Symptom Development ◽  
Cyanogenic Glucosides ◽  
Fungal Development ◽  
Cyanogenic Potential ◽  
Trifolium Repens L ◽  
Whole Mounts

White clover (Trifolium repens L.) contains two cyanogenic β-glucosides (G), linamarin and lotaustralin. Upon injury to the tissues a β-glucosidase (E) effects the release of cyanide from the β-glucosides. Four selections of white clover differing in cyanogenic properties (G+E+, G+E−, G−E+, G−E−) were examined for differences in susceptibility to Stemphylium sarciniforme. Symptom development was determined at 24, 48, 72, 96, and 120 h after the leaves were inoculated. Symptoms for all four selections consisted initially of small brown flecks (1 mm in diameter), then dark spots (1–2 mm in diameter) with definite borders, and finally senescence and wilt of the interlesion tissue. Plants containing both β-glucosidase (EC 3.2.1.21)and cyanogenic glucosides (G+E+) and those with only glucosides (G+E−) developed symptoms 24 h earlier than did the G−E+ and G−E− selections. The earliest symptoms were observed at 48 h; by 96 h all four selections showed comparable degrees of senescence and wilt. Pathogen development in infected leaves prepared as whole mounts was examined microscopically. Through 72 h after inoculation, development of S. sarciniforme in the G+E+ and G+E− selections was slower than in the G−E+ selections. By 96 h, however, fungal development in all four selections was comparable; commencement of leaf senescence coincided with extensive fungal colonization of necrotic tissue. Accelerated rates of symptom expression and retarded pathogen development apparently were positively correlated with cyanogenic potential of each white clover selection. Necrosis of suscept tissue was not correlated with cyanogenic potential of each selection.

SSH reveals a linkage between a senescence-associated protease and Verticillium wilt symptom development in lettuce (Lactuca sativa)

2011 ◽  
Vol 76 (1) ◽  
pp. 48-58 ◽  
Author(s):  
Steven J. Klosterman ◽  
Amy Anchieta ◽  
Maria D. Garcia-Pedrajas ◽  
Karunakaran Maruthachalam ◽  
Ryan J. Hayes ◽  
...  
Keyword(s):  
Verticillium Wilt ◽  
Lactuca Sativa ◽  
Symptom Development ◽  
Wilt Symptom

scholarly journals Development, Detection, and Elimination of Verticillium dahliae in Mint Shoot Cultures

HortScience ◽  
2003 ◽  
Vol 38 (1) ◽  
pp. 67-70 ◽  
Author(s):  
Nan Wang ◽  
Barbara M. Reed
Keyword(s):  
Verticillium Dahliae ◽  
Shoot Tips ◽  
Potato Dextrose Agar ◽  
Shoot Length ◽  
Symptom Expression ◽  
Shoot Cultures ◽  
Symptom Development ◽  
Symptom Ratings ◽  
Wilt Symptom

Roots of greenhouse-grown mint plants and in-vitro-grown shoot cultures were inoculated with Verticillium dahliae Kleb. conidial suspensions to study wilt symptom development and detection and elimination of the fungus. There were significant differences in the symptom expression between control and infected shoot cultures at all conidia concentrations for the four mints tested. Disease-symptom ratings were proportional to the V. dahliae inoculum density. Infected shoot cultures were stunted when inoculated with ≥ 103 conidia/mL. Verticillium dahliae was re-isolated from infected shoot cultures at all levels of inoculum, but not from any control cultures. Verticillium infections were easily detected by plating mint stems on potato dextrose agar. Shoot tips (0.5 to 15 mm) from infected in-vitro- and greenhouse-grown plants were isolated and screened for fungus. The most effective shoot length for fungus elimination was 3-5 mm. Shoot tips isolated from in vitro spearmint cultivars infected at 102 and 103 conidia/mL were 100% Verticillium free, but only 42% of `Black Mitcham' and 54% of `Todd's Mitcham' peppermints were free of the disease. Shoot tips from infected greenhouse plants produced Verticillium-free cultures from 79% of `Black Mitcham' and 90% of `Todd's Mitcham' plants. These results indicate the utility of testing for Verticillium and the safety of micropropagated mint shoots for certified planting stock programs.

An evaluation of potential seed treatments to control Fusarium solani f.sp. phaseoli, the cause of foot and root rot of Phaseolus vulgaris

1977 ◽  
Vol 89 (1) ◽  
pp. 235-238 ◽  
Author(s):  
P. E. Russell ◽  
A. E. A. Mussa
Keyword(s):  
Phaseolus Vulgaris ◽  
Fusarium Solani ◽  
Root Rot ◽  
Similar Pattern ◽  
Fungal Growth ◽  
Systemic Fungicide ◽  
Product Concentration ◽  
Low Concentrations ◽  
High Concentrations

SummaryTwo systemic fungicides, benomyl and thiabendazole, were more active than the non-systemic fungicide Drazoxolon in inhibiting fungal growth in vitro. A similar pattern was obtained in glasshouse trials with benomyl and thiabendazole giving adequate protection at low concentrations while Drazoxolon was ineffective unless applied at 50% the commercial product concentration. A field trial using thiabendazole, Drazoxolon and a mixture of benomyl and thiram confirmed the glasshouse results.Some phytotoxicity was noticed with high concentrations of both benomyl and thiabendazole, but satisfactory disease control was achieved using fungicide concentrations which did not induce phytotoxicity.

scholarly journals Performance of Fungal Growth Through Integrated Gompertz Model and Respiratory Quotient by Solid State Fermentation in Multi-Layer Squared Tray Solid State Bioreactor with Aeration Strategies

2021 ◽  
Author(s):  
Musaalbakri Abdul Manan ◽  
Colin Webb
Keyword(s):  
Solid State ◽  
Solid State Fermentation ◽  
Respiratory Quotient ◽  
Fungal Growth ◽  
Gompertz Model ◽  
Solid Substrate ◽  
Aspergillus Awamori ◽  
Promising Alternative ◽  
Fungal Activity ◽  
On Line

Abstract A newly designed, laboratory-scaled and multi-layer squared tray solid state bioreactor (SSB), was developed and successfully operated in solid state fermentation (SSF) conditions. The bioreactor was divided into eight layers of squared perforated trays. Wheat bran was used as a solid substrate for the growth of Aspergillus awamori and Aspergillus oryzae. The SSB was equipped with an oxygen (O2)/carbon dioxide (CO2) gas analyser and a thermocouple. Continuous on-line monitoring of fungal growth could be performed by indirect methods that measure O2 consumed, production of CO2 and metabolic heat. The advantage of using this method is that there are no tedious and time-consuming sampling processes. The evolution of CO2, which represents an accumulation term, was integrated with time and fitted to the Gompertz model in a log-like equation. The Gompertz model generated values that may be used to stimulate and verify the experimental data. Results strongly suggest that the evolved and accumulated CO2, excellently described fungal growth. Simulated results agreed with experimental results. The respiratory quotient (RQ), which is the ratio of CO2 evolution rate (CER) to O2 uptake rate (OUR), was determined by the gas balance method. CER and OUR confirmed that measurements correlated to fungal activity. Each RQ values can explain the differences of each SFF process carried out. Yet, heat evolved by fungal activity also described fungal growth. The current findings is an excellent pre-liminary experimental work, evidencing that multi-layer squared tray SSB with forced moistened aeration present a promising alternative of instrumented bioreactors for SSF processes.

scholarly journals Chestnut Drying Is Critical in Determining Aspergillus flavus Growth and Aflatoxin Contamination

Toxins ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 530 ◽  
Author(s):  
Simona Prencipe ◽  
Ilenia Siciliano ◽  
Carlotta Gatti ◽  
Maria Gullino ◽  
Angelo Garibaldi ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Fungal Growth ◽  
Aflatoxin Production ◽  
Aflatoxin Contamination ◽  
Total Phenol ◽  
Fungal Colonization ◽  
Total Phenol Content ◽  
Phenol Content ◽  
Drying Treatment ◽  
Drying Conditions

Chestnut drying is used to prevent postharvest losses and microorganism contamination during storage. Several studies reported the contamination by aflatoxins (AFs) produced by Aspergillus spp. in chestnuts. The effect of drying temperatures (from 30 to 50 °C) was evaluated on the growth of A. flavus and the production of aflatoxins in chestnuts. The influence of the treatment on the proximate composition, the total phenol content and antioxidant activity of chestnuts was considered. Fungal colonization was observed on the nuts dried at 30, 35, and 40 °C; the incidence was lower at 40 °C. The highest concentrations of AFB1 and AFB2 were produced at 40 °C. No aflatoxins were detected at 45 or 50 °C. At 40 °C A. flavus was under suboptimal conditions for growth (aw 0.78), but the fungus was able to synthesize aflatoxins. As the temperatures applied increased, the total phenol content increased, while the antioxidant activity decreased. A drying treatment at 45 °C for seven days (aw 0.64) could be a promising method to effectively control both the growth of aflatoxigenic fungi and the production of aflatoxins. This study provides preliminary data useful to improve the current drying conditions used in chestnut mills, to reduce both fungal growth and aflatoxin production.

Vascular coating: a barrier to colonization by the pathogen in Verticillium wilt of tomato

1989 ◽  
Vol 67 (2) ◽  
pp. 600-607 ◽  
Author(s):  
Jane Robb ◽  
D. A. Powell ◽  
P. F. S. Street
Keyword(s):  
Disease Resistance ◽  
Verticillium Wilt ◽  
Water Samples ◽  
Light Microscope ◽  
Trapping Site ◽  
Symptom Expression ◽  
Susceptible Tomato ◽  
Ve Gene ◽  
Verticillium Albo Atrum

Massive infusion of conidia of Verticillium albo-atrum Reinke & Berthier induced synchronous secretion of vascular coating in the petiolar xylem vessels of resistant and susceptible tomato near-isolines. More coating formed earlier in resistant than in susceptible plants. In the susceptible plants secretion was delayed in colonized trapping site vessels, but initiated in surrounding uncolonized ones. Controls were infused with water. Samples were quantified by light microscope assay techniques at 18, 48, and 120 h postinoculation for the following parameters: (i) delayed coating effect, (ii) overall coating capacity, and (iii) ability of fungus to "escape" laterally from trapping site vessels. The results showed that susceptibility to Verticillium was absolutely correlated with the presence of the delayed coating effect in the plant and increased ability of the fungus to spread laterally. Treatment of inoculated resistant plants with an inhibitor of coating secretion resulted in conversion to the susceptible phenotype. The progeny of a genetic backcross for the dominant (Ve) and recessive (ve) alleles at the Ve locus (Velve × velve) were assayed for the same parameters as well as for disease resistance based on symptom expression. The results confirmed the previous observations and suggested that in tomato the delayed phenotype is recessive. The data strongly supports two hypotheses: (i) coating forms a barrier against fungal penetration and (ii) the timing of the coating response in trapping site vessels results, directly or indirectly, from expression of the Ve gene.

scholarly journals Hop Polyphenols in Relation to Verticillium Wilt Resistance and Their Antifungal Activity

Plants ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1318
Author(s):  
Sabina Berne ◽  
Nataša Kovačević ◽  
Damijana Kastelec ◽  
Branka Javornik ◽  
Sebastjan Radišek
Keyword(s):  
Phenolic Compounds ◽  
Antifungal Activity ◽  
Verticillium Wilt ◽  
Molecular Mechanisms ◽  
Induced Defense ◽  
Fungal Growth ◽  
Defense Responses ◽  
Resistant Variety ◽  
Phenological Stages ◽  
Total Polyphenols

(1) Background: Verticillium wilt (VW) of hop is a devastating disease caused by the soil-borne fungi Verticillium nonalfalfae and Verticillium dahliae. As suggested by quantitative trait locus (QTL) mapping and RNA-Seq analyses, the underlying molecular mechanisms of resistance in hop are complex, consisting of preformed and induced defense responses, including the synthesis of various phenolic compounds. (2) Methods: We determined the total polyphenolic content at two phenological stages in roots and stems of 14 hop varieties differing in VW resistance, examined the changes in the total polyphenols of VW resistant variety Wye Target (WT) and susceptible Celeia (CE) on infection with V. nonalfalfae, and assessed the antifungal activity of six commercial phenolic compounds and total polyphenolic extracts from roots and stems of VW resistant WT and susceptible CE on the growth of two different V. nonalfalfae hop pathotypes. (3) Results: Generally, total polyphenols were higher in roots than stems and increased with maturation of the hop. Before flowering, the majority of VW resistant varieties had a significantly higher content of total polyphenols in stems than susceptible varieties. At the symptomatic stage of VW disease, total polyphenols decreased in VW resistant WT and susceptible CE plants in both roots and stems. The antifungal activity of total polyphenolic extracts against V. nonalfalfae was higher in hop extracts from stems than those from roots. Among the tested phenolic compounds, only p-coumaric acid and tyrosol markedly restricted fungal growth. (4) Conclusions: Although the correlation between VW resistance and total polyphenols content is not straightforward, higher levels of total polyphenols in the stems of the majority of VW resistant hop varieties at early phenological stages probably contribute to fast and efficient activation of signaling pathways, leading to successful defense against V. nonalfalfae infection.

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