Pathogenicity of Phytophthora × alni Isolates Obtained from Symptomatic Trees, Soil and Water against Alder

Phytophthora alni complex (P. × alni, P. × multiformis, P. uniformis) are pathogens attacking alder seedlings and trees, causing significant losses in nurseries and natural tree stands. Decay of alder trees has been observed in Poland for over a dozen years. Overall, 25 Polish isolates of P. × alni obtained from symptomatic alder trunks, rhizosphere soil surrounding infected trees, and nearby natural streams were compared with isolates from symptomatic trunks obtained in France, Belgium and Hungary. Morphologic characterization of mycelium, vegetative and generative organs, temperature effect on mycelium growth, and their pathogenicity were studied. The mycelium growth rate of isolates from symptomatic plants was fastest on Carrot Agar (CA) medium, and from soil and water on Vegetable Agar (V8A) medium. The sizes of zoosporangia varied depending on their origin. The isolates that originated from the soil had the largest zoosporangia. The diameter of the oogonia and antheridia did not differ regardless of their origin. The results of pathogenicity tests of P. × alni isolates obtained from different sources showed that the soil isolates were the most aggressive in each test, followed by the isolates from the trunks and water. A simple test of leaf colonization can give an idea of the aggressiveness of the isolate towards the shoots and roots. No morphological or physiological markers of aggressiveness have been found.

The effect of different substrates on oyster mushroom (Pleurotus ostreatus) spawn growth

The study aimed to find alternative substrates for growing spawn of oyster mushroom (Pleurotus ostreatus). The experiment was laid out in a completely randomized design with three compositions of substrates. The substrate compositions were: (1) Substrate A (corn 100%), (2) Substrate B (corn and sawdust mix in a ratio of (1:1, v/v)), and (3) Substrate C (corn and sawdust mix in a ratio of (3:1, v/v)). All compositions were replicated 18 times. The complete colonization (days) and mycelium growth rate (cm day−1) were recorded. Means were analyzed by Analysis of Variance (ANOVA) and duncan test was performed if there were significant between the substrate compositions. The results showed that substrate C was the best substrate indicated with the fastest complete colonization of 14.17±0.92 and the highest growth rate of 0.85±0.06 cm day−1.

Aggressiveness and trichothecene production of Fusarium graminearum isolates from cereals in Serbia

The aim of this study was to assess variations in aggressiveness and trichothecene production of F. graminearum isolates originating from maize, wheat and barley in Serbia. Analyzing F. graminearum isolates (98) obtained from various agroecological conditions of Serbia over the period from 1993 to 2010, using the HPLC method, the following two chemotypes were observed: 3-acetyl-deoxinivalenol (3ADON) and 15-acetyl-deoxinivalenol (15ADON). A great diversity in the production of deoxinivalenol (DON) derivatives was observed. A majority of F. graminearum isolates, regardless of their origin (maize, wheat or barley) belonged to the 15ADON chemotype. The 3ADON chemotype was also detected, but in a significantly smaller number (13/98) samples, compared to the 15ADON chemotype (85/98). None of the tested isolates belonged to the NIV chemotype. The examined isolates showed different pathogenicity on barley leaf, wheat class and maize ears. The average pathogenicity of the tested isolates was the highest on barley leaf. It was observed that isolates originating from wheat had the highest average daily increase in mycelium growth rate (27.37 mm). Statistical analysis of the obtained results for mycotoxins synthesis showed that there was a highly significant statistical correlation between the production potentials of total DON, 3ADON and 15ADON in F. graminearum isolates belonging to various chemotypes. However, there was no statistically significant correlation between the aggressiveness of isolates and the production of total DON in isolates belonging to 3ADON and 15ADON chemotypes.

Potential Of Various Types of Media for Breeding Oyster Mushroom F2

This research was conducted at the Laboratory of Biotechnology 1 and Farmers' Land in Karanganyar village, Poncokusumo, Malang. The materials used in this study were white oyster mushroom F1 seeds, 70% alcohol, soybean seeds, corn seeds, rice, sawdust, rice bran and mushroom baglog. This study used an experimental design, namely Completely Randomized Design (CRD) with 8 treatment levels B1 = corn kernels (100%), B2 = soybean seeds (100%), B3 = rice (100%), B4 = sawdust (100%), B5 = corn kernels (50%) + sawdust (40%) + rice bran (10%). Parameters observed were height of Mycelium-covered Media (cm), Mycelium Growth Speed (cm/day), Contamination Occurrence Percentage (%). The average yield of the highest seedling height was 12.79 cm in treatment B8. The parameter of mycelium growth rate in B8 treatment had the fastest growth rate of 1.82 cm/ha. The lowest contamination was found in treatment B5, B6 by 4% and B7 by 20%. Treatment B3, B4 and B8 did not experience contamination.

Design and synthesis of novel n-butyphthalide derivatives as promising botanical fungicides

In order to obtain novel botanical fungicides, three series of novel 6-substituted n-butyphthalide derivatives have been designed and synthesized via nucleophilic addition, reduction, nitrification, amination, sulfonation, Sandmeyer and Suzuki reaction. The mycelium growth rate method was used to evaluate the inhibition activity against eight phytopathogenic fungi in vitro. Preliminary bioassay tests showed that compounds 6f, 6n, 6p, 6r and 7a exhibited better activity for some fungi at 50 μg/mL than the positive drug hymexazol and lead compound n-butyphthalide (NBP). The preliminary structure–activity relationships indicated that the antifungal activity is significantly affected by the substituents on the benzene ring.

Evaluation of Biomass and Chitin Production of Morchella Mushrooms Grown on Starch-Based Substrates

Morchella sp. is one of the most expensive mushrooms with a high nutritional profile. In this study, the polysaccharide content of Morchella species was investigated. Specifically, mycelium growth rate, biomass production, sclerotia formation, and glucosamine and total polysaccharides content of six Morchella species grown on a starch-based media were evaluated. Submerged fermentations in potato dextrose broth resulted in a glucosamine content of around 3.0%. In solid-state fermentations (SSF), using potato dextrose agar, a high linear growth rate (20.6 mm/day) was determined. Increased glucosamine and total polysaccharides content were observed after the formation of sclerotia. Biomass and glucosamine content were correlated, and the equations were used for the indirect estimation of biomass in SSF with agro-industrial starch-based materials. Wheat grains (WG), potato peels (PP), and a mixture of 1:1 of them (WG–PP) were evaluated as substrates. Results showed that the highest growth rate of 9.05 mm/day was determined on WG and the maximum biomass yield (407 mg/g) on WG–PP. The total polysaccharide content reached up to 18.4% of dried biomass in WG–PP. The results of the present study proved encouraging for the efficient bioconversion of potato and other starch-based agro-industrial waste streams to morel biomass and sclerotia eliciting nutritional and bioactive value.

Novel Inulin Derivatives Modified with Schiff Bases: Synthesis, Characterization, and Antifungal Activity

In this paper, we report chemical modifications of inulin by seven kinds of aromatic Schiff bases, which are different from their substituent groups. The obtained inulin derivatives were confirmed by FTIR, 1H NMR, and 13C NMR. Then, we studied their antifungal activity against four kinds of plant pathogens involving Botrytis cinerea, Fusarium oxysporum f. sp. cucumerium Owen, Fusarium oxysporum f. sp. niveum, and Phomopsis asparagi by the mycelium growth rate method. The results revealed that all inulin derivatives were endowed with significant antifungal activity compared to inulin. Among them, 6-amino-(N-4-chlorobenzylidene)-6-deoxy-3,4-di-O-acetyl inulin (4CBSAIL) and 6-amino-(N-3,4-dichlorobenzylidene)-6-deoxy-3,4-di-O-acetyl inulin (3,4DCBSAIL), which were synthesized from p-chlorobenzaldehyde and 3,4-dichlorobenzaldehyde, could completely inhibit the growth of the test fungi at 1.0 mg/mL. The inhibitory indices of the inulin derivatives were related to the type, position, and number of substituent groups (halogens) on the Schiff bases. The results confirmed that it was feasible to chemically modify inulin with Schiff bases to confer high antifungal activity to inulin. The products described in this paper have great potential as alternatives to some harmful pesticides used for plant disease control.

Morphological Characteristics and Genetic Variability of Trichoderma spp. From Conventional Cotton Crop Soils in Federal District, Brazil

This study aimed to characterize 41 isolates of Trichoderma from conventional cotton crops soils as the morphological and cultural characteristics and to investigate polymorphism, using RAPD markers. The most common group comprised 80.6% of the isolates and was identified as a strain of Trichoderma harzianum. The others species were T. aureoviride (7.3%), T. viride (7.3%) and T. crassum (4.8%). The four species were morphologically distinct in the evaluated characteristics such as colony appearance and mycelium growth rate after being grown on malt extract agar (MEA), potato dextrose agar (PDA) and oatmeal agar (OA) media, and also in shape of conidia, phialides, and conidiophores. The four species were separated in a dendogram, after using RAPD markers. Besides, RAPD was efficient in demonstrating the high intraspecific genetic variation among isolates of two species (T. harzianum and T. aureoviride).

Synthesis of Luminescent Ag Nanoclusters with Antibacterial Activity

This paper focuses on the synthesis of novel Ag nanoclusters (NCs) using DHLA as capping reagents in aqueous solution by a photoreduction method. Luminescence studies indicated that the DHLA-Ag NCs exhibited strong blue emission with maximum peak at 480 nm. The maximum emission of the NCs can be greatly improved with irradiating time by around 15-fold from 3 h to 67 h. By means of mycelium growth rate, the results showed that the Ag NCs with smaller sizes had a good antimicrobial effect.