Valdensinia heterodoxa Peyronel as a New Pathogen of Blueberry in Poland.

Valdensia leaf blight on blueberry in Poland was reported in one commercial nursery plantation near Prazmów, Mazovia voivodship, where heavy defoliation was observed on cv. Bluecrop, grown in nursery pots, in August 2011. Older fruiting bushes were only slightly affected by the disease. Initial symptoms of the disease were small, oval to circular zonated necrosis surrounded with dark brown borders that enlarged on the leaves throughout the canopy. Multicellular, hyaline or light brown, star-shaped conidiospores were observed on the necrotic areas. The mean length of 50 conidiospores from the end of head to the end of arm apex was 307 to 348 µm (4). Eight single-spore isolates of the fungus were obtained. Single conidiospores were picked up from necrotic spots on leaves and transferred with sterile needle on potato dextrose agar (PDA) and incubated at 20°C under ambient light. After 10 days of incubation, total DNA was extracted. Amplification of the internal transcribed spacer (ITS) region of rDNA was done using primers ITS1F and ITS4A (1). PCRs were carried out as follows: initial denaturation at 94°C for 2 min, denaturation at 94°C for 1 min, annealing at 57°C for 1 min, extension at 72°C for 1 min, and final extension at 72°C for 5 min for 28 cycles (Applied Biosystems Veriti 96 Wel Thermal Cycler). Amplicons, which were approximately 520 bp, were sequenced and nucleotide sequences were analyzed by Clustal W2EBI. The sequences of all eight isolates showed 100% similarity to each other and were compared with sequences stored in GenBank using BLAST. Sequences were 525 bp long and showed 100% homology to Valdensinia heterodoxa Peyronel, Sclerotiniaceae (anamorph: Valdensia heterodoxa Peyronel) from Japan and Norway (Accession Nos. AB663682 and Z81447, respectively) (3). The sequence from one isolate was submitted to GenBank (Accession No. KF212190). To fulfill Koch's postulates, each of the eight isolates was used to inoculate 20 healthy young leaves of Vaccinium corymbosum L. cv. Bluecrop and bilberry (V. myrtillus L.) (10 leaves per plant). Mycelial plugs 5 mm in diameter were taken from PDA cultures, approximately 20 days old, and used as inoculum and placed in the center of each leaf and moistened with sterile distilled water. Mycelium-free plugs were used as control. Inoculated leaves were placed in plastic box and incubated at 20°C in laboratory for 5 days, at which time small necrotic lesions consistent with initial symptoms of the disease were observed. Isolates obtained from these symptoms were morphologically identical to those used for inoculation. Control leaves did not show any disease symptoms. Valdensia leaf blight occurrence may be attributed to rainy July and August 2011 and long presence of water on soil surface. In Poland, Valdensinia heterodoxa causes heavy defoliation of Vaccinium myrtillus in pine stands and is a common pathogen of some herbaceous plants (2). To our knowledge, this is the first report of Valdensia leaf blight on highbush blueberry in Poland. References: (1) I. Larena et al. 75:187, 1999. (2) W. Mulenko and S. Woodward. Mycologist 10:69, 1996. (3) S. Nekoduka et al. J. Gen. Plant Pathol. 78:151, 2012. (4) S. Zhao and S. F. Shamoun. Mycology 1:113, 2010.

Kinetics of fumonisin B1 formation in maize ears inoculated with Fusarium verticillioides.

The kinetics of fumonisin B1 (FB1) biosynthesis have been examined in ears of four botanical varieties Zea mays var. indentata, Zea mays var. indurata, Zea mays var. saccharata and Zea mays var. everta inoculated with F. verticillioides isolates at silking stage. The level of mycotoxin accumulated in kernels was correlated with sample harvest time (r = 0.73) and ergosterol content (r = 0.70). FB1 biosynthesis was influenced by amylose, starch and moisture contents, which undergo dynamic changes during grain formation. A comparative analysis of ear infection rates and efficiency of FB1 biosynthesis showed that these are separate characters and their expression could be independent.

Moniliformin In wheat and triticale grain.

Fusarium avanacoum infected wheat and triticale heads in Poland in each season between 1985 and 1989. The average number of heads infected byF avonacaum was 26 % for wheat and 46 % for triticale out of all examined heads withFusarium head blight symptoms.Fusarium-damaged wheat grain, naturally infected byF avenaceum, contained an average of 15.9±7.7 mg moniliformin/kg, healthy looking kernels from the same heads an average of 0.42±0.19 mg moniliformin/kg. Fusarfum-damaged kernels of triticale contained an average of 3.5 mg moniliformin/kg while healthy looking kernels from the same ears contained 0.25 mg/kg.

Susceptibility of selected winter wheat cultivars produced in Poland to Fusarium head blight.

The susceptibility of six winter wheat cultivars toFusarium head blight has beenstudied. The lowest infected plants intensity, mean degree of head damage and fusariosis index exhibited cultivar Grana which also cumulated the lowest amount of trichothecenes (DON and derivatives ). Possibility to produce NIV by Polish strains has been found.in F.graminearum.

A study of the correlation between the amount of deoxynivalenol in grain of wheat and triticale and percentage ofFusarium damaged kernels.

The correlation between the amount of deoxynivalenol (DON) and the percentage ofFusarium damaged kernels (FDK) in samples of wheat and triticale was studied.Samples of naturally infected wheat grain, collected in 1986, 1987 and 1988 and of triticale collected in 1986 were used.Additionally, artificial inoculated wheat samples (10 genotypes inoculated with 3F. Culmorum strains of weak, medium and severe pathogenicity and samples of 10 triticale genotypes inoculated withF. culmorum. andF. graminearun) were studied. Using statistical methods (the variance analysis, method of least significant difference (LSD), orthogonal contrast (OC) and minimum within groups sum of squares criterion (MSSC)), the samples were divided into two groups with respect to the attribute DON/FDK.To the first group belong samples of wheat and triticale, of which the heads were artificially inoculated with severely pathogenic strainsF. culmorum. In the samples of this group the amount of DON in kernels damaged withFusarium increased by 0,46 mg/kg per 1% of FDK.In the second group, consisting of naturally infected samples and samples from artificially inoculated heads the amount of DON increased 0,30 mg DON/kg per 1% of FDK.The equation for the calculation of approximated amount of DON in farm and commercial lots of wheat and triticale after examination of percentage of FDK is given.

Toxinogenicity ofMicrodochium nivale (Fusarium nivale) isolates from cereals in Poland.

Microdochium nivale (Fusarium nivale) was found to be frequently occuring in Poland pathogen of small grain cereals heads, causing symptoms similar to those observed after infection ofFusarium species. In consecutive years since 1985 till 1989 the following percentage of wheat and rye ears infected withM. Nivale and withFusarium head blight symptoms was found: 34%, 21%, 42%, 9%, 46% (wheat) and 57%, 43%, 65%, 4%, 47% (rye) heads.However, in naturally infected rye and wheat samples (kernels and chaff), we did not detect toxins usually present in samples infected with fungi of genusFusarium - such as deoxynivalenol and derivatives. TypicalFusarium trichothecene metabolites were also not present in cultures of 11M. nivale strains, growing 3-5 weeks on rice (45% water content) at 20°C. Cultures of two typical isolates on wheat grain (strain KF 1124) and on rice (KF 245) were found to be non toxic to broiler chickens when present in amount 20-40% in their diet. It can be concluded thatM. nivale (F. nivale) representatives in Poland did not produce toxic metabolites neither under laboratory condition nor after cereal ears infection under field conditions.

Mycotoxins in cereal grain. Part 13. Deoxynivalenol and 3-acetyl-deoxynivalenol in wheat kernels and chaff with head fusariosis symptoms.

In the period of harvest at 1987 field samples of wheat heads with fusariosis symptoms were collected in 18 provinces of Poland. Subsamples of heads infected with Fusarium culmorum (W.G.Sm) Sacc. and Fusarium graminearum Schwabe were analyzed for Fusarium metabolites. In fractions of kernels with visible Fusarium-damage deoxynivalenol (DON) was present in average amount of 18.7 mg/kg (range 9.6-25.3 mg/kg) and 3-acetyl DON 1.9 mg/kg. Fractions of kernels without symptoms of visible Fusarium-damage contained only DON at average 2 mg/kg (range 0.8-3.6 mg/kg). A method of approximate calculation of DON content in a given lot of grain is proposed which may be realized during samples grading.

Mycotoxins in cereal grain. Part 14. Histochemical examination of Fusarium-damaged wheat kernels.

Wheat kernels with visible Fusarium-damage, naturally infected, have been examined with histochemical techniques to observe mycelium growth inside kernels and change in kernels cells. Kernels infected with F. culmorum were found to be damaged more extensively, comparatively to those infected with F. graminearum, F. avenaceum and F. nivale/(Microdochium nivale). Growth of Fusarium mycelium was most abundant between pericarp and aleurone layer and alongside of scutellum. Mycelium colonized also endosperm and embryo--both plumula and radicula.

Deoxynivalenol and 3-acetyldeoxynivalenol and Fusarium species in winter triticale.

Fusarium species infecting heads of Triticale and mycotoxins presence in infected kernels and chaff were studied during two seasons. The most important species observed on infected heads were in 1986F. avenaceum (39%),F. nivale (21%),F. culmorum (20%),F. graminearum (14%), and others (6%). In 1987 after long and snowy winterF. nivale dominated (64%), followed byF. avenaceum (24%),F. culmorum (6%), andF. graminearum (5%).The mycotoxins deoxynivalenol (DON) and 3-acetyl DON were present in all 11 subsamples of kernels from heads infected byF. culmorum and/orF. Graminearum (1.6-16.4 mg and 0.7-2.4mg/kg, respectively). Chaff from the same subsamples contained 9.9-33.2mg/kg of DON and 5.2-16.0mg/kg of 3-AcDON. Kernels with visibleFusarium-damage contained 2.4-31.2 mg/kg of DON and 1.2-6.0 mg/kg of 3-AcDON. Remaining part of kernels without symptoms of visibleFusarium-damage contained only DON in an amount of 0.9-5.9 mg/kg.

Mycotoxins and fungi accompanying wheat head fusariosis in Poland.

The occurrence of wheat head fusariosis in various regions of Poland was observed in 1985 and 1986. The incidence of fusariosis was usually low - about 0,01% - only on South - East in some localities reached 5 - 20%. The most important species isolated from infected heads were :Fusarium culmorum F.grami nearurn,F.ni vale andF.avenaceum, in addition to whichF.crookwel1ense,F.eqiseti,F.subqluti nans andF.tricinctum (sensu Nelson et al.1983) were observed. Deoxynivalenol was present in 100% examined kernels subsamples at level 5-18 mg/kg and 3-acetyl deoxyn i val enol in 70% at level 1-3 mg/kg. The mycotoxins amount in chaff was 1,4 to 2,6 and 1,4 to 11 times higher (DON and 3AcD0N resp.) than in kernels.

Phytotoxicity of metabolites formed by Fusaria to cereal seedlings.

Phytotoxicity of 37 isolates of seven species ofFusarium has been studied. Metabolites of tested species exhibited signficantly different phototoxicity towards cereal seedlings. Germination was in greatest extent inhibited by metabolites ofF. subglutinans, in smallest extent by metabolites ofF. tricinctum /respectively 50% and 8%/. The growth rate of wheat seedlings was most strongly retarded by metabolites ofF. crookwellense, metabolites ofF. tricictum inhibited growth in the lowest percentage 57% and 29% respectively.