scholarly journals Effect of acidity on growth rate and stroma formation of Monilia fructigena and M. polystroma isolates

Author(s):  
I. J. Holb

The effect of acidity (pH) ranges on the mycelial growth and stroma formation of Monilia fructigena Pers: Fr. and of M. polystroma van Leeuwen was determined on agar plates and apple fruits. Four isolates of each of the brown rot fungi and two apple cultivars, `James Grieve' and 'Cox's Orange Pippin', were used for the study. For the agar plate study, a range of the initial pH was prepared from 2.5 to 6.5. The dishes were inoculated with a 4 mm plug of each isolate and incubated at 23 °C in darkness. The mycelial growth was measured after 1.5, 4, 7, 10 and 20 days of incubation. After a 30-day incubation, stroma formation was determined by image analysis and weighing of mature stroma. In the fruit experiment, both cultivars were inoculated with one isolate of M. fructigena and of M. polystroma. The pH changes were determined after 7, 14, 28 and 35 days of incubation in both healthy and inoculated fruits. The fastest mycelial growth was at pH 4.5 for M. polystroma and at pH 3.5 for M. fructigena. After a 30-day incubation, M. polystroma isolates produced twice or three times more stroma compared to M. fructigena isolates. For both brown rot fungi, the amount of mature stroma increased from pH 3.5 to 5.5, and then decreased at pH 6.5. Results of the.fruit experiment showed that healthy fruits were quite acidic (pH < 3.5), but pH rapidly increased in the inoculated fruits for both cultivars, reaching pH 4.6-5.4 depending on cultivar and fungus isolate. On both cultivars, the stroma developed at a significantly higher pH for M. polystroma than for M. fructigena. Biological and practical implications of the results are discussed.

1998 ◽  
Vol 76 (12) ◽  
pp. 2042-2050 ◽  
Author(s):  
GCM van Leeuwen ◽  
H A van Kesteren

The three Monilinia spp., known as the brown rot fungi of fruit crops, are usually distinguished from each other on the basis of (qualitative) colony characteristics. We linked these qualitative features to unambiguously defined, quantitative colony and germ tube characteristics. A wide collection of isolates of Monilinia fructicola (Winter) Honey, Monilinia laxa (Aderhold & Ruhland) Honey, and Monilinia fructigena (Aderhold & Ruhland) Honey was used to determine growth rate and sporulation intensity on potato dextrose agar (PDA) at 22°C under two light regimes (darkness, 12 h light : 12 h dark). The following germ tube characteristics were determined on water agar after incubation for 18 h at 22°C in darkness: length of the (leading) germ tube, distance to the first branch, and the number of germ tubes per conidium. Increase in colony diameter from day 3 to day 5 and sporulation intensity measured after 14 days was the highest in M. fructicola, whilst M. laxa and M. fructigena showed considerable overlap in these features. The length of the germ tube after 18 h incubation was shortest in M. laxa, ranging from 161 to 466 µm. In M. fructicola and M. fructigena these ranges were 465-851 and 307-806 µm, respectively. The occurrence of more than one germ tube per conidium was most prominent in M. fructigena. Discriminant analysis on the basis of different combinations of the quantitative characteristics measured, showed that the combination of growth rate on PDA and length of the germ tube was sufficient to delineate the three brown rot fungi. One of 11 M. fructicola isolates was misclassified, the same held for M. fructigena (one misclassification of nine isolates). No misclassifications occurred in M. laxa.Key words: brown rot fungi, growth characteristics, Monilinia spp., taxonomy.


Holzforschung ◽  
2006 ◽  
Vol 60 (3) ◽  
pp. 339-345 ◽  
Author(s):  
Anne Christine Steenkjær Hastrup ◽  
Bo Jensen ◽  
Carol Clausen ◽  
Frederick Green III

AbstractThe dry rot fungus,Serpula lacrymans, is one of the most destructive copper-tolerant fungi causing timber decay in buildings in temperate regions. Calcium and oxalic acid have been shown to play important roles in the mechanism of wood decay. The effect of calcium on growth and decay was evaluated for 12 strains ofS. lacrymansand compared to five brown-rot fungi. This was done by treating copper citrate (CC)-treated Southern yellow pine (SYP) wood with a CaCl2solution and estimating the decay rate and amount of soluble oxalic acid in an ASTM soil block test. Decay byS. lacrymanswas found to be significantly inhibited by treatment with CaCl2in the presence of copper. In addition, calcium showed no effect on two strains ofS. lacrymansand oneSerpula himantioidesstrain in non-copper-treated SYP wood blocks. The growth rate ofS. lacrymanswas not affected on malt extract agar containing CaCl2. In summary, a marked decrease was observed in the decay capacity ofS. lacrymansin pine treated with CC+CaCl2. The amount of soluble oxalic acid was measured in CC-treated blocks and blocks also treated with CaCl2. Of the comparative brown-rot fungi, bothAntrodia vaillantii(TFFH 294) andPostia placenta(Mad 698) displayed notable wood decay despite CaCl2treatment, while the remaining strains were inhibited.


Holzforschung ◽  
2013 ◽  
Vol 67 (1) ◽  
pp. 99-106 ◽  
Author(s):  
Anne Christine Steenkjær Hastrup ◽  
Trine Østergaard Jensen ◽  
Bo Jensen

Abstract The presence of iron-chelating and iron-reducing compounds has been evaluated qualitatively and quantitatively in the four brown rot fungi Meruliporia incrassata (M. incrassata), Gloeophyllum trabeum (G. trabeum), Coniophora puteana (C. puteana) and Serpula lacrymans (S. lacrymans). Samples of actively growing mycelium from liquid growth media, decayed wood, and agar plate cultures were in focus. Iron-chelating compounds were found in all four species, with the highest reactivity in G. trabeum and S. lacrymans, and the lowest in M. incrassata. Iron-reducing activity, measured in the liquid medium, was found in all four fungi. However, in wood extractions, S. lacrymans was not effective in this regard, although the agar grown mycelium of this fungus showed the highest iron-reducing capacity of the four. The presence of both catecholate and hydroxamate chelators was detected in all four species. G. trabeum showed the highest concentration overall of extracellular chelators, including both catecholate and hydroxamate derivatives.


Agronomy ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1814
Author(s):  
Rachid Lahlali ◽  
Ouafae Mchachti ◽  
Nabil Radouane ◽  
Said Ezrari ◽  
Zineb Belabess ◽  
...  

Monilinia fructigena is one of the most important fungal pathogens causing brown rot on apple and is heavily affecting fruit production. The main objective of this study was to screen for potential bacterial isolates with higher antagonistic activity against M. fructigena. Our study focused on the identification of potential bacterial isolates capable of reducing both the mycelial growth of M. fructigena and the disease severity using in vitro and in planta trials, respectively. To achieve this goal, thirteen bacteria, isolated from natural soil, were evaluated for their abilities to produce lytic enzymes (amylase, cellulase and protease), hydrocyanic acid (HCN) and lipopeptides (bacillomycin, fengycin, iturin and surfactin). Further, results from the dual culture method, volatile and bacterial free-cell filtrate bioassays indicated that tested isolates showed a fungicidal activity against the mycelial growth of M. fructigena. Thus, out of the 13 isolates tested, 12 exhibited significant mycelial inhibition (more than 70%) against M. fructigena, while remaining the last isolate displayed only a partial inhibition (up to 43%). Further, 12 of the bacteria isolates displayed an amylase production, 10 showed cellulase production, 11 revealed protease production, while only 2 displayed HCN production. In addition, most bacterial isolates were found to have genes encoding for different lipopeptides: bacillomycin (10), fengycin (3), iturin (11) and surfactin (1). Interestingly, two bacterial isolates, Bacillus amyloliquefaciens B10W10 and Pseudomonas sp. B11W11 were found to be the most effective and displayed the lowest disease severity in planta trial. These two bacteria reduced the brown rot incidence compared to the synthetic fungicide in a semi-commercial large-scale trial. Therefore, our findings suggest that these two later bacterial isolates provide apple protection against M. fructigena via direct and indirect mechanisms. These isolates may be used, therefore, as potential biological control agents (BCAs) in preventive treatment to control brown rot disease on apple fruits.


Holzforschung ◽  
2001 ◽  
Vol 55 (6) ◽  
pp. 568-572 ◽  
Author(s):  
T.H. Fisher ◽  
Y. Jin ◽  
T.P. Schultz

Summary Twenty 3′-substituted-3-stilbenols were synthesized and tested for fungicidal activity (agar plate IC50 values) against two brown-rot fungi rot Gloeophyllum trabeum and Postia placenta and one white-rot fungus Trametes versicolor. Compounds synthesized were eight trans-3-X-3′-stilbenols (X = OMe, Me, Cl, OH, OPr, OBu, OOct, and O-p-Tol), three cis-3-X-3′-stilbenols (X = OMe, Me, Cl), three 3-hydroxy-α-(3-X-phenyl)cinnamic acids (X = OMe, Me, Cl), and six multisubstituted-3′-substituted-3-stilbenols (3′,4-diOMe, 3′-Me-4-OMe, 3′-Cl-4-OMe, 3′-OH-4-OMe, 3′-Cl-4-OMe-4′-OH, and 3′-Cl-4′-OH). The three cinnamic acids and 3′-OOct showed low to no activity against all three fungi. Most of these 3′-substituted-3-stilbenols (15 of 20) had fungicidal activity against the white-rot fungus T. versicolor, in contrast to earlier studies on 3′-substituted-4-stilbenols which were inactive against T. versicolor. These 3′-substituted-3-stilbenols also had fungicidal activity against G. trabeum and P. placenta, with the latter fungus having a parabolic lipophilic Quantitative Structure Activity Relationship (QSAR). 3′-O-p-Tol-3-stilbenol was the most active against T. versicolor and fifth most active against P. placenta of the twenty 3′-substituted-3-stilbenols examined here.


2017 ◽  
Vol 68 (3) ◽  
pp. 474-477
Author(s):  
Lacramioara Oprica ◽  
Doina Atofanei ◽  
Vladimir Poroch

The amounts of anthocyanins, flavonoids, total polyphenol and ascorbic acid in seven apple cultivars from Romania were investigated. The amounts of polyphenol and flavonoids in pulp and skin of apple cultivars ranged between 17.18�7.52 mg GAE/g DW and 20.10�11.06 mg CE/g DW as well as 3.64�1.18 mg GAE/g DW and 10.31�5.57 mg CE/g DW, respectively. The highest and smallest values of ascorbic acid both in the skin and the pulp were observed in the cultivars Mutsu and Starkrimson. The anthocyanin content is positively correlated with the colour intensity of the apple epicarp, being about three-fold higher in Prima than Golden Delicious cultivar. The better antioxidant activity provided by the content of polyphenol, ascorbic acid and flavonoids was in apple fruits of Mutsu cultivar and for this reason it should be regarded as a valuable source of antioxidants.


Catalysts ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 668
Author(s):  
Justine Oma Angadam ◽  
Seteno Karabo Obed Ntwampe ◽  
Boredi Silas Chidi ◽  
Jun Wei Lim ◽  
Vincent Ifeanyi Okudoh

Human endeavors generate a significant quantity of bio-waste, even lignocellulosic waste, due to rapid industrialization and urbanization, and can cause pollution to aquatic ecosystems, and contribute to detrimental animal and human health because of the toxicity of consequent hydrolysis products. This paper contributes to a new understanding of the lignocellulosic waste bio-pretreatment process from a literature review, which can provide better biorefinery operational outcomes. The simultaneous partial biological lignin, cellulose and hemicellulose lysis, i.e., simultaneous semi-lignino-holocellulolysis, is aimed at suggesting that when ligninolysis ensues, holocellulolysis is simultaneously performed for milled lignocellulosic waste instead of having a sequential process of initial ligninolysis and subsequent holocellulolysis as is currently the norm. It is presumed that such a process can be solely performed by digestive enzyme cocktails from the monkey cups of species such as Nepenthes, white and brown rot fungi, and some plant exudates. From the literature review, it was evident that the pretreatment of milled lignocellulosic waste is largely incomplete, and ligninolysis including holocellulolysis ensues simultaneously when the waste is milled. It is further proposed that lignocellulosic waste pretreatment can be facilitated using an environmentally friendly approach solely using biological means. For such a process to be understood and applied on an industrial scale, an interdisciplinary approach using process engineering and microbiology techniques is required.


Agronomy ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 209
Author(s):  
Nadia Lyousfi ◽  
Rachid Lahlali ◽  
Chaimaa Letrib ◽  
Zineb Belabess ◽  
Rachida Ouaabou ◽  
...  

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.


Holzforschung ◽  
2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Liselotte De Ligne ◽  
Jan Van den Bulcke ◽  
Jan M. Baetens ◽  
Bernard De Baets ◽  
Gang Wang ◽  
...  

AbstractThe effect of fungicidal components in wood has been known for ages, yet there is no method to assess the impact of such components on the durability of a wood species, as compared to other material characteristics that influence decay. In this paper, the importance of fungicidal effects on the natural durability of 10 wood species is assessed in relation to other decay-influencing factors with a new test, the so-called ‘paste test’. By comparing results from this test with the ‘mini-block test’, on both heartwood and leached sapwood, insight is gained into the significance of fungicidal components on the one hand and other material characteristics on the other hand. The durability of species such as Prunus avium was attributed mainly to fungicidal components. For species such as Pterocarpus soyauxii, durability seemed to be an effect of both fungicidal components and moisture-regulating components, while the latter seemed to be of main importance in regulating the decay of Aucoumea klaineana and Entandrophragma cylindricum. Wood-anatomical features, such as the parenchyma content (in case of brown rot fungi) and the vessel-fiber ratio, possibly affect degradation as well. This work shows that fungicidal components are not always of major importance for the durability of a wood species. The authors hereby emphasize the importance of moisture-regulating components and wood anatomy on the durability of wood.


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