Toward Breeding for Resistance to Fusarium Tuber Rot in Caladium: Inoculation Technique and Sources of Resistance

Fusarium tuber rot, incited by Fusarium solani, is the major cause of losses of tuber quality and quantity in caladium (Caladium ×hortulanum) during storage and production. To develop a reliable inoculation method for evaluating cultivar susceptibility to Fusarium tuber rot and identifying sources of resistance, the effect of temperature on the mycelial growth of F. solani in vitro and on tuber rot in vivo was examined. The optimal temperature was then used to study the aggressiveness of F. solani isolates. The effect of temperature (13, 18, 23, 28, and 33 °C) on radial mycelial growth of nine F. solani isolates in vitro was determined, and all responded similarly to temperature variables, with optimal growth predicted to be at 30.5 °C. The relationship of these temperatures to disease development was then determined for the most aggressive F. solani isolate 05-20 and it was found that disease development in inoculated tubers was greatest at low temperatures (13 and 18 °C). Cold damage to tubers was observed at 13 °C; therefore, 18 °C was chosen for all future disease screening. The aggressiveness of nine isolates was tested on two caladium cultivars. Significant differences among isolates were observed for the diameter of rotted tissue in both cultivars, indicating that choice of isolate was important for screening. Isolates 05-20 and 05-257 were highly aggressive on both cultivars. Tubers of 17 commercial caladium cultivars were inoculated with three isolates (04-03, 05-20, and 05-527) and incubated at 18 °C. The interaction between isolates and cultivars was highly significant (P < 0.0001), indicating that cultivars were not equally susceptible to different pathogenic isolates of F. solani. Lesion diameters differed significantly (P < 0.0001) among cultivars/isolates and ranged from 9.5 mm (‘Rosebud’ and ‘White Christmas’ for isolate 04-03) to 23.9 mm (‘Carolyn Whorton’ for isolate 05-20). The cultivars were ranked for susceptibility to tuber rot within each isolate and the normalized total rank for the three isolates was used to place cultivars into four categories: resistant (‘Candidum’, ‘Rosebud’, ‘White Christmas’, ‘Florida Sweetheart’, and ‘Aaron’), moderately resistant (‘White Wing’ and ‘Red Flash’), susceptible (‘Candidum Jr.’, ‘White Queen’, ‘Red Frill’, ‘Florida Cardinal’, ‘Miss Muffet’, and ‘Postman Joyner’), and highly susceptible (‘Fannie Munson’, ‘Gingerland’, ‘Frieda Hemple’, and ‘Carolyn Whorton’). The availability of these sources of host plant resistance, aggressive isolates, and resistance assessment techniques will facilitate the development of new Fusarium-resistant caladium cultivars.

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Light Intensity Alters the Behavior of Monilinia spp. in vitro and the Disease Development on Stone Fruit-Pathogen Interaction

Frontiers in Plant Science ◽

10.3389/fpls.2021.666985 ◽

2021 ◽

Vol 12 ◽

Author(s):

Marta Balsells-Llauradó ◽

Rosario Torres ◽

Núria Vall-llaura ◽

Carla Casals ◽

Neus Teixidó ◽

...

Keyword(s):

Ethylene Production ◽

Growth Parameters ◽

Abiotic Factors ◽

Brown Rot ◽

Stone Fruit ◽

Effect Of Temperature ◽

Disease Development ◽

Fruit Bagging

The development of brown rot caused by the necrotrophic fungi Monilinia spp. in stone fruit under field and postharvest conditions depends, among others, on environmental factors. The effect of temperature and humidity are well studied but there is little information on the role of light in disease development. Herein, we studied the effect of two lighting treatments and a control condition (darkness) on: (i) several growth parameters of two Monilinia spp. (M. laxa and M. fructicola) grown in vitro and (ii) the light effect in their capacity to rot the fruit (nectarines) when exposed to the different lighting treatments. We also assessed the effect of such abiotic factors in the development of the disease on inoculated nectarines during postharvest storage. Evaluations also included testing the effect of fruit bagging on disease development as well as on ethylene production. Under in vitro conditions, lighting treatments altered colony morphology and conidiation of M. laxa but this effect was less acute in M. fructicola. Such light-induced changes under in vitro development also altered the capacity of M. laxa and M. fructicola to infect nectarines, with M. laxa becoming less virulent. The performance of Monilinia spp. exposed to treatments was also determined in vivo by inoculating four bagged or unbagged nectarine cultivars, indicating an impaired disease progression. Incidence and lesion diameter of fruit exposed to the different lighting treatments during postharvest showed that the effect of the light was intrinsic to the nectarine cultivar but also Monilinia spp. dependent. While lighting treatments reduced M. laxa incidence, they enhanced M. fructicola development. Preharvest conditions such as fruit bagging also impaired the ethylene production of inoculated fruit, which was mainly altered by M. laxa and M. fructicola, while the bag and light effects were meaningless. Thus, we provide several indications of how lighting treatments significantly alter Monilinia spp. behavior both in vitro and during the interaction with stone fruit. This study highlights the importance of modulating the lighting environment as a potential strategy to minimize brown rot development on stone fruit and to extent the shelf-life period of fruit in postharvest, market, and consumer’s house.

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An Attempt at Biological Control of Blossom Blight of Rose Caused by Botrytis cinerea Using some Local Trichoderma spp. Strains

Acta Phytopathologica et Entomologica Hungarica ◽

10.1556/038.55.2020.010 ◽

2020 ◽

Vol 55 (1) ◽

pp. 27-34

Author(s):

G. Zadehdabagh ◽

K. Karimi ◽

M. Rezabaigi ◽

F. Ajamgard

Keyword(s):

Botrytis Cinerea ◽

Mycelial Growth ◽

Limiting Factor ◽

Dual Culture ◽

Trichoderma Spp ◽

Khuzestan Province ◽

Inhibitory Potential ◽

Cut Rose

The northern of Khuzestan province in Iran is mainly considered as one of the major areas of miniature rose production. Blossom blight caused by Botrytis cinerea has recently become a serious limiting factor in rose production in pre and post-harvest. In current study, an attempt was made to evaluate the inhibitory potential of some local Trichoderma spp. strains against B. cinerea under in vitro and in vivo conditions. The in vitro results showed that all Trichoderma spp. strains were significantly able to reduce the mycelial growth of the pathogen in dual culture, volatile and non-volatile compounds tests compared with control, with superiority of T. atroviride Tsafi than others. Under in vivo condition, the selected strain of T. atroviride Tsafi had much better performance than T. harzianum IRAN 523C in reduction of disease severity compared with the untreated control. Overall, the findings of this study showed that the application of Trichoderma-based biocontrol agents such as T. atroviride Tsafi can be effective to protect cut rose flowers against blossom blight.

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Applicability of Instability Index for In vitro Protein Stability Prediction

Protein and Peptide Letters ◽

10.2174/0929866526666190228144219 ◽

2019 ◽

Vol 26 (5) ◽

pp. 339-347 ◽

Cited By ~ 4

Author(s):

Dilani G. Gamage ◽

Ajith Gunaratne ◽

Gopal R. Periyannan ◽

Timothy G. Russell

Keyword(s):

Protein Stability ◽

Caulobacter Crescentus ◽

Effect Of Temperature ◽

Instability Index ◽

Dipeptide Composition ◽

Experimental Conditions ◽

The Stability ◽

Vitro Protein

Background: The dipeptide composition-based Instability Index (II) is one of the protein primary structure-dependent methods available for in vivo protein stability predictions. As per this method, proteins with II value below 40 are stable proteins. Intracellular protein stability principles guided the original development of the II method. However, the use of the II method for in vitro protein stability predictions raises questions about the validity of applying the II method under experimental conditions that are different from the in vivo setting. Objective: The aim of this study is to experimentally test the validity of the use of II as an in vitro protein stability predictor. Methods: A representative protein CCM (CCM - Caulobacter crescentus metalloprotein) that rapidly degrades under in vitro conditions was used to probe the dipeptide sequence-dependent degradation properties of CCM by generating CCM mutants to represent stable and unstable II values. A comparative degradation analysis was carried out under in vitro conditions using wildtype CCM, CCM mutants and two other candidate proteins: metallo-β-lactamase L1 and α -S1- casein representing stable, borderline stable/unstable, and unstable proteins as per the II predictions. The effect of temperature and a protein stabilizing agent on CCM degradation was also tested. Results: Data support the dipeptide composition-dependent protein stability/instability in wt-CCM and mutants as predicted by the II method under in vitro conditions. However, the II failed to accurately represent the stability of other tested proteins. Data indicate the influence of protein environmental factors on the autoproteolysis of proteins. Conclusion: Broader application of the II method for the prediction of protein stability under in vitro conditions is questionable as the stability of the protein may be dependent not only on the intrinsic nature of the protein but also on the conditions of the protein milieu.

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Influence of Light Conditions and Medium Composition on Morphophysiological Characteristics of Stevia rebaudiana Bertoni In Vitro and In Vivo

Horticulturae ◽

10.3390/horticulturae7070195 ◽

2021 ◽

Vol 7 (7) ◽

pp. 195

Author(s):

Alla A. Shulgina ◽

Elena A. Kalashnikova ◽

Ivan G. Tarakanov ◽

Rima N. Kirakosyan ◽

Mikhail Yu. Cherednichenko ◽

...

Keyword(s):

Culture Media ◽

Stevia Rebaudiana ◽

Adventitious Shoot ◽

Optimal Growth ◽

Medium Composition ◽

Light Spectra ◽

Stevia Rebaudiana Bertoni ◽

Multiplication Coefficient

We investigated the influence of different conditions (light composition and plant growth regulators (PGRs) in culture media) on the morphophysiological parameters of Stevia rebaudiana Bertoni in vitro and in vivo. Both PGRs and the light spectra applied were found to significantly affect plant morphogenesis. During the micropropagation stage of S. rebaudiana, optimal growth, with a multiplication coefficient of 15, was obtained in an MS culture medium containing 2,4-epibrassinolide (Epin) and indole-3-acetic acid (IAA) at concentrations of 0.1 and 0.5 mg L−1, respectively. During the rooting stage, we found that the addition of 0.5 mg L−1 hydroxycinnamic acid (Zircon) to the MS medium led to an optimal root formation frequency of 85% and resulted in the formation of strong plants with well-developed leaf blades. Cultivation on media containing 0.1 mg L−1 Epin and 0.5 mg L−1 IAA and receiving coherent light irradiation on a weekly basis resulted in a 100% increase in the multiplication coefficient, better adventitious shoot growth, and a 33% increase in the number of leaves. S. rebaudiana microshoots, cultured on MS media containing 1.0 mg L−1 6-benzylaminopurine (BAP) and 0.5 mg L−1 IAA with red monochrome light treatments, increased the multiplication coefficient by 30% compared with controls (white light, media without PGRs).

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Improving the Biocontrol Potential of Bacterial Antagonists with Salicylic Acid against Brown Rot Disease and Impact on Nectarine Fruits Quality

Agronomy ◽

10.3390/agronomy11020209 ◽

2021 ◽

Vol 11 (2) ◽

pp. 209

Author(s):

Nadia Lyousfi ◽

Rachid Lahlali ◽

Chaimaa Letrib ◽

Zineb Belabess ◽

Rachida Ouaabou ◽

...

Keyword(s):

Salicylic Acid ◽

Disease Severity ◽

Mycelial Growth ◽

Brown Rot ◽

Antagonistic Bacteria ◽

Biological Treatments ◽

Rot Disease ◽

The Impact

The main objective of this study was to evaluate the ability of both antagonistic bacteria Bacillus amyloliquefaciens (SF14) and Alcaligenes faecalis (ACBC1) used in combination with salicylic acid (SA) to effectively control brown rot disease caused by Monilinia fructigena. Four concentrations of salicylic acid (0.5%, 2%, 3.5%, and 5%) were tested under in vitro and in vivo conditions. Furthermore, the impact of biological treatments on nectarine fruit parameters’ quality, in particular, weight loss, titratable acidity, and soluble solids content, was evaluated. Regardless of the bacterium, the results indicated that all combined treatments displayed a strong inhibitory effect on the mycelial growth of M. fructigena and disease severity. Interestingly, all SA concentrations significantly improved the biocontrol activity of each antagonist. The mycelial growth inhibition rate ranged from 9.79% to 88.02% with the highest reduction rate recorded for bacterial antagonists in combination with SA at both concentrations of 0.5% and 3.5%. The in vivo results confirmed the in vitro results with a disease severity varying from 0.00% to 51.91%. A significant biocontrol improvement was obtained with both antagonistic bacteria when used in combination with SA at concentrations of 0.5% and 2%. The lowest disease severity observed with ACBC1 compared with SF14 is likely due to a rapid adaptation and increase of antagonistic bacteria population in wounded sites. The impact of all biological treatments revealed moderate significant changes in the fruit quality parameters with weight loss for several treatments. These results suggest that the improved disease control of both antagonistic bacteria was more likely directly linked to both the inhibitory effects of SA on pathogen growth and induced fruit resistance.

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An optimised GAS-pharyngeal cell biofilm model

Scientific Reports ◽

10.1038/s41598-021-87377-7 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Heema K. N. Vyas ◽

Jason D. McArthur ◽

Martina L. Sanderson-Smith

Keyword(s):

Crystal Violet ◽

Biofilm Formation ◽

Cell Model ◽

Matrix Material ◽

Three Dimensional ◽

Growth Period ◽

Optimal Growth ◽

Abiotic Surfaces

AbstractGroup A Streptococcus (GAS) causes 700 million infections and accounts for half a million deaths per year. Biofilm formation has been implicated in both pharyngeal and dermal GAS infections. In vitro, plate-based assays have shown that several GAS M-types form biofilms, and multiple GAS virulence factors have been linked to biofilm formation. Although the contributions of these plate-based studies have been valuable, most have failed to mimic the host environment, with many studies utilising abiotic surfaces. GAS is a human specific pathogen, and colonisation and subsequent biofilm formation is likely facilitated by distinct interactions with host tissue surfaces. As such, a host cell-GAS model has been optimised to support and grow GAS biofilms of a variety of GAS M-types. Improvements and adjustments to the crystal violet biofilm biomass assay have also been tailored to reproducibly detect delicate GAS biofilms. We propose 72 h as an optimal growth period for yielding detectable biofilm biomass. GAS biofilms formed are robust and durable, and can be reproducibly assessed via staining/washing intensive assays such as crystal violet with the aid of methanol fixation prior to staining. Lastly, SEM imaging of GAS biofilms formed by this model revealed GAS cocci chains arranged into three-dimensional aggregated structures with EPS matrix material. Taken together, we outline an efficacious GAS biofilm pharyngeal cell model that can support long-term GAS biofilm formation, with biofilms formed closely resembling those seen in vivo.

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Control of lettuce bottom rot by isolates of Trichoderma spp

Summa Phytopathologica ◽

10.1590/0100-5405/1968 ◽

2014 ◽

Vol 40 (2) ◽

pp. 141-146 ◽

Cited By ~ 4

Author(s):

Zayame Vegette Pinto ◽

Matheus Aparecido Pereira Cipriano ◽

Amaury da Silva dos Santos ◽

Ludwig Heinrich Pfenning ◽

Flávia Rodrigues Alves Patrício

Keyword(s):

Mycelial Growth ◽

High Capacity ◽

Dry Weight ◽

Second Step ◽

Trichoderma Spp ◽

In Vivo Experiments ◽

Bottom Rot ◽

Trichoderma Isolates

Bottom rot, caused by Rhizoctonia solani AG 1-IB, is an important disease affecting lettuce in Brazil, where its biological control with Trichoderma was not developed yet. The present study was carried out with the aim of selecting Trichoderma isolates to be used in the control of lettuce bottom rot. Forty-six Trichoderma isolates, obtained with baits containing mycelia of the pathogen, were evaluated in experiments carried out in vitro and in vivo in a greenhouse in two steps. In the laboratory, the isolates were evaluated for their capabilities of parasitizing and producing toxic metabolic substances that could inhibit the pathogen mycelial growth. In the first step of the in vivo experiments, the number and the dry weight of lettuce seedlings of the cultivar White Boston were evaluated. In the second step, 12 isolates that were efficient in the first step and showed rapid growth and abundant sporulation in the laboratory were tested for their capability of controlling bottom rot in two repeated experiments, and had their species identified. The majority of the isolates of Trichoderma spp. (76%) showed high capacity for parasitism and 50% of them produced toxic metabolites capable of inhibiting 60-100% of R. solani AG1-IB mycelial growth. Twenty-four isolates increased the number and 23 isolates increased the dry weight of lettuce seedlings inoculated with the pathogen in the first step of the in vivo experiments.In both experiments of the second step, two isolates of T. virens, IBLF 04 and IBLF 50, reduced the severity of bottom rot and increased the number and the dry weight of lettuce seedlings inoculated with R. solani AG1-IB. These isolates had shown a high capacity for parasitism and production of toxic metabolic substances, indicating that the in vitro and in vivo steps employed in the present study were efficient in selecting antagonists to be used for the control of lettuce bottom rot.

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Evaluation of Bioagents and Biopesticides against Colletotrichum lindemuthianum and its Integrated Management in Common Bean

Notulae Scientia Biologicae ◽

10.15835/nsb234772 ◽

2010 ◽

Vol 2 (3) ◽

pp. 72-76 ◽

Cited By ~ 4

Author(s):

Bilal Ahmad PADDER ◽

Prem Nath SHARMA ◽

Renu KAPIL ◽

Anju PATHANIA ◽

Om Prakash SHARMA

Keyword(s):

Mycelial Growth ◽

Integrated Management ◽

Trichoderma Viride ◽

Significant Inhibition ◽

Colletotrichum Lindemuthianum ◽

Maximum Inhibition ◽

Gliocladium Virens ◽

Foliar Treatment

Three bioagents (Trichoderma viride, T. harzianum and Gliocladium virens) and five biopesticides (Achook, Neemgold, Wannis, Spictaf and Neemazal) were evaluated under in vitro and in vivo conditions against Colletotrichum lindemuthianum. All the three antagonistic fungi caused significant inhibition of mycelial growth, maximum being with T. viride (69.21%) followed by T. harzianum (64.20%). Among the biopesticides tested at four concentrations, Wanis applied @ 1000 ?l/ml caused maximum inhibition of 82.12 per cent followed by Spictaf (52.85%). T. viride and Wanis @ 1000 ?l/ml were most effective in reducing the seed borne infection. Integration of bioagents with Bavistin showed that disease can be effectively managed with seed dressing either with Bavistin or biopesticide followed by foliar treatment with fungicide or biopesticide.

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Bioactivity of volatile organic compounds by Aureobasidium species against gray mold of tomato and table grape

World Journal of Microbiology and Biotechnology ◽

10.1007/s11274-020-02947-7 ◽

2020 ◽

Vol 36 (11) ◽

Author(s):

A. Di Francesco ◽

J. Zajc ◽

N. Gunde-Cimerman ◽

E. Aprea ◽

F. Gasperi ◽

...

Keyword(s):

Volatile Organic Compounds ◽

Organic Compounds ◽

Mycelial Growth ◽

Solid Phase ◽

Table Grape ◽

Conidial Suspension ◽

Vitro Assay ◽

Volatile Organic

Abstract Aureobasidium strains isolated from diverse unconventional environments belonging to the species A. pullulans, A. melanogenum, and A. subglaciale were evaluated for Volatile Organic Compounds (VOCs) production as a part of their modes of action against Botrytis cinerea of tomato and table grape. By in vitro assay, VOCs generated by the antagonists belonging to the species A. subglaciale showed the highest inhibition percentage of the pathogen mycelial growth (65.4%). In vivo tests were conducted with tomatoes and grapes artificially inoculated with B. cinerea conidial suspension, and exposed to VOCs emitted by the most efficient antagonists of each species (AP1, AM10, AS14) showing that VOCs of AP1 (A. pullulans) reduced the incidence by 67%, partially confirmed by the in vitro results. Conversely, on table grape, VOCs produced by all the strains did not control the fungal incidence but were only reducing the infection severity (< 44.4% by A. pullulans; < 30.5% by A. melanogenum, and A. subglaciale). Solid-phase microextraction (SPME) and subsequent gas chromatography coupled to mass spectrometry identified ethanol, 3-methyl-1-butanol, 2-methyl-1-propanol as the most produced VOCs. However, there were differences in the amounts of produced VOCs as well as in their repertoire. The EC50 values of VOCs for reduction of mycelial growth of B. cinerea uncovered 3-methyl-1-butanol as the most effective compound. The study demonstrated that the production and the efficacy of VOCs by Aureobasidium could be directly related to the specific species and pathosystem and uncovers new possibilities for searching more efficient VOCs producing strains in unconventional habitats other than plants.

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Temperature dependence of oxygen diffusion and consumption in mammalian striated muscle

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1993.264.6.h1825 ◽

1993 ◽

Vol 264 (6) ◽

pp. H1825-H1830 ◽

Cited By ~ 21

Author(s):

T. B. Bentley ◽

H. Meng ◽

R. N. Pittman

Keyword(s):

Diffusion Coefficient ◽

Steady State ◽

Oxygen Diffusion ◽

Striated Muscle ◽

Effect Of Temperature ◽

Retractor Muscle ◽

Oxygen Solubility ◽

Order Of Magnitude

This study investigated the effect of temperature on the oxygen diffusion coefficient (DO2) of hamster retractor muscle from 11 to 37 degrees C. DO2 was measured using a non-steady-state technique, whereas muscle O2 consumption (VO2) was estimated after steady state was reached. DO2 was 0.84 +/- 0.04 x 10(-5) cm2/s at 11 degrees C and rose exponentially to 2.41 +/- 0.19 x 10(-5) cm2/s at 37 degrees C, producing a temperature coefficient for DO2 of 4.60%/degrees C for this temperature range. To measure DO2 directly at 37 degrees C, it was necessary to inhibit tissue VO2 with Amytal. The DO2 measurements made at 37 degrees C were significantly higher than previously reported values, which had been based on extrapolations from lower temperatures (6). Further analysis suggests a possible transition in the diffusion pathway between 23 and 30 degrees C, resulting in a DO2 higher than that previously expected. This larger DO2, together with a recently published value of oxygen solubility (alpha) (21), results in an in vitro Krogh's diffusion coefficient (KO2) that is 2.4 times larger than that previously reported (24) and therefore significantly reduces an order of magnitude discrepancy between in vitro and estimated in vivo KO2 values (24). Muscle VO2 was 0.35 ml O2.min-1.100 g-1 at 11 degrees C and increased with temperature, resulting in an activation energy of the rate-limiting reaction from the Arrhenius equation of -10.5 kcal/mol between 11 and 30 degrees C.

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