Effects of salicylic acid on the growth and pathogenicity of Zymoseptoria tritici

Introduction: Zymoseptoria tritici, is a species of filamentous fungus and causes the widespread wheat disease Septoria tritici blotch (STB). Salicylic acid has a key role in plant defence reactions and is also involved in the induction of systemic acquired resistance. However, the contribution of SA to the interaction of Z. tritici -wheat in STB is not entirely clear.In this study, it was shown that the Z. tritici mycelial growth and conidia germination were significantly inhibited the presence of increasing concentration of SA in both liquid and solid media. In addition, the effect of SA on pathogenicity of Z. tritici in wheat was investigated. Materials and methods: In this study, the inhibitory effect of SA on Z. tritici at different concentrations (1 to 20 mM) in vitro, and also, the efficacy of its exogenous application in the suppression of STB in wheat under the greenhouse condition were investigated. In vitro evaluation was done on YMDA and YMDB to determine the effect of SA on the germination of conidia and growth of mycelium, respectively.  Susceptible bread wheat cultivar was grown in pot and inoculated with fungus spores and SA in a three-leaf stage for green house experiments. Results: The results showed that the germination ofconidia was completely inhibited by 4 mM SA. Furthermore, in modified YMDA plates at over 0.8 mM, the colonies diameter was reduced significantly. The result of in planta assay indicated that the foliar application of 4 mM SA can significantly reduce the disease symptoms on the wheat leaves. Discussion and conclusion: Regarding our data, it seems that SA shows more inhibitory effect in in vitro experiments than in planta. Moreover, according to the positive effects of SA on STB, the survey results can be considered as a potential approach in the management of this disease

Response of Wheat (Triticum aestivum L.) to Spent Mushroom Compost under Different Moisture Conditions

The effect of spent mushroom compost (SMC) on yield and yield components of wheat (cv. Azar2) under different moisture conditions was evaluated in pot experiment at Dry-land Agricultural Research Institute in 2010. Experiment arrangement was factorial based on complete randomized design with four replications. Treatments were SMC at three levels (0, 25 and 50 Mg.ha-1) and water deficit stress at three levels (-0.3 or field capacity, -5 and -10 bar). Some morphological, yield and yield components of wheat were determined. Results indicated that water stress had a negative and significant (

Multilayer perceptron-genetic algorithm as a promising tool for modeling cultivation substrate of Auricularia cornea Native to Iran

Auricularia cornea Ehrenb (syn. A. polytricha) is a wood-decaying fungi known as black ear mushroom. Earlike gelatinous fruiting body distinguishes them from other fungi. Industrial wastes have the potential to be used as the basic substrate to produce mushrooms. Therefore, 16 substrate formulations were prepared from different ratios of beech (BS) and hornbeam sawdust (HS) supplemented with wheat (WB) and rice brans (RB). The pH and initial moisture content of substrate mixtures were adjusted to 6.5 and 70%, respectively. The comparison of in vitro growth characteristics of the fungal mycelia under the different temperatures (25, 28, and 30°C), and culture media [yeast extract agar (YEA), potato extract agar (PEA), malt extract agar (MEA), and also HS and BS extract agar media supplemented with maltose, dextrose, and fructose revealed that the highest mycelial growth rate (MGR; 7.5 mm/day) belonged to HS and BS extract agar media supplemented with three mentioned sugar at 28°C. In A. cornea spawn study, the substrate combination of BS (70%) + WB (30%) at 28°C and moisture contents of 75% displayed the highest mean MGR (9.3 mm/day) and lowest spawn run period (9.0 days). In the bag test, “BS (70%) + WB (30%)” was the best substrate displaying the shortest spawn run period (19.7 days), and the highest fresh sporophore yield (131.7 g/bag), biological efficiency (53.1%) and number of basidiocarp (9.0/bag) of A. cornea. Also, A. cornea cultivation was processed to model yield, biological efficiency (BE), spawn run period (SRP), days for pinhead formation (DPHF), days for the first harvest (DFFH), and total cultivation period (TCP) by multilayer perceptron-genetic algorithm (MLP-GA). MLP-GA (0.81–0.99) exhibited a higher predictive ability than stepwise regression (0.06–0.58). The forecasted values of the output variables were in good accordance with their observed ones corroborating the good competency of established MLP-GA models. MLP-GA modeling exhibited a powerful tool for forecasting and thus selecting the optimal substrate for maximum A. cornea production

Multilayer perceptron-genetic algorithm as a promising tool for modeling cultivation substrate of Auricularia cornea Native to Iran.

Auricularia cornea Ehrenb (syn. A. polytricha) is a wood-decaying fungi known as black ear mushroom. Earlike gelatinous fruiting body distinguishes them from other fungi. Industrial wastes have the potential to be used as the basic substrate to produce mushrooms. Therefore, 16 substrate formulations were prepared from different ratios of beech (BS) and hornbeam sawdust (HS) supplemented with wheat (WB) and rice brans (RB). The pH and initial moisture content of substrate mixtures were adjusted to 6.5 and 70%, respectively. The comparison of in vitro growth characteristics of the fungal mycelia under the different temperatures (25, 28, and 30°C), and culture media [yeast extract agar (YEA), potato extract agar (PEA), malt extract agar (MEA), and also HS and BS extract agar media supplemented with maltose, dextrose, and fructose revealed that the highest mycelial growth rate (MGR; 7.5 mm/day) belonged to HS and BS extract agar media supplemented with three mentioned sugar at 28°C. In A. cornea spawn study, the substrate combination of BS (70%) + WB (30%) at 28°C and moisture contents of 75% displayed the highest mean MGR (9.3 mm/day) and lowest spawn run period (9.0 days). In the bag test, "BS (70%) + WB (30%)" was the best substrate displaying the shortest spawn run period (19.7 days), and the highest fresh sporophore yield (131.7 g/bag), biological efficiency (53.1%) and number of basidiocarp (9.0/bag) of A. cornea. Also, A. cornea cultivation was processed to model yield, biological efficiency (BE), spawn run period (SRP), days for pinhead formation (DPHF), days for the first harvest (DFFH), and total cultivation period (TCP) by multilayer perceptron-genetic algorithm (MLP-GA). MLP-GA (0.81-0.99) exhibited a higher predictive ability than stepwise regression (0.06-0.58). The forecasted values of the output variables were in good accordance with their observed ones corroborating the good competency of established MLP-GA models. MLP-GA modeling exhibited a powerful tool for forecasting and thus selecting the optimal substrate for maximum A. cornea production

Evaluation of genetic diversity among some commercial cultivars and wild Iranian strains of Agaricus bisporus by microsatellite markers

Agaricus bisporus is the most widely cultivated mushroom in Iran. Lack of diversity in mushroom crops especially where disease is concerned, creates a crucial risk in the currently grown cultivars. The aim of this study was to assess the genetic diversity among Iranian wild strains and some commercial cultivars by using microsatellite markers. Eighteen codominant microsatellite markers of A. bisporus (AbSSR) were used to distinguish 17 wild and commercial strains. All the microsatellite markers used in this research gave clear banding patterns and only one strain remained undistinguished. Among 106 generated alleles the wild subgroup presented 53 alleles never found both in brown and white commercial cultivars and 42 alleles never found in commercial brown strains. The dendrogram obtained by UPGMA clustering analysis separated A.bisporus strains into six groups. Based on our results, the high level of genetic diversity among Iranian wild strains, compared with the commercial strains, provides a new and promising source of diversity for A. bisporus breeding programs. To our knowledge this is the first relevant study of biodiversity in native Iranian populations of A. bisporus.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Effect of cropping systems and arbuscular mycorrhizal fungi on soil microbial activity and root nodule nitrogenase

Forage legumes are used to enhancement soil fertility of the agro ecosystem. Understanding effect of them on agro ecosystem soil status during when these legumes growing and after that is essential. In one experiment the effects of inoculation with the arbuscular mycorrhizal fungi (AMF), Glomus mosseae, and mixed cropping systems (MCS) on forage biomass yield, nitrogen production, nitrogenase activity and after harvesting on soil microbial activity were studied at various mixed cropping ratios of berseem clover (Trifolium alexandrinum L., B) to Persian clover (Trifolium resupinatum L., P) (B:P = 1:0, 3:1, 1:1, and 1:3). In the second experiment, the effect of treatments on soil microbial activity were studied by soil collection after clover harvesting and 8-week soil incubations in the laboratory. MCS had positive effects on root and shoot dry weight. The effects of AMF on plant yield were positive. AMF affected the fraction root and the vertical root distribution. Plants colonized by AMF showed shorter roots than control plants. At cut 1, with the AMF colonization, the greatest nitrogenase activity (79.61 μmol C2H4 g dwt−1 h−1) of root nodule was observed with B:P = 3:1. At cut 2, the Persian clover plants colonized by G. mosseae in the mixed crop (1:3) had a higher nitrogenase activity (77.38 μmol C2H4 g dwt−1 h−1). The greatest nitrogen accumulation in the aboveground biomass, 23.5 mg g−1 forage dry matter, was obtained with mixed cropping (B:P = 1:1) in the presence of the AMF colonization. Microbial activity measured as substrate-induced respiration and activities of dehydrogenase, alkaline phosphatase, and acid phosphatase enzymes responded positively to AMF colonization; with the greatest activities for B:P = 1:3

The ZtVf1 transcription factor regulates development and virulence in the foliar wheat pathogen Zymoseptoria tritici

The dimorphic fungal pathogen, Zymoseptoria tritici undergoes discrete developmental changes to complete its life cycle on wheat. Molecular mechanisms underlying morphogenesis during infection process of Z. tritici are poorly understood. In this study, we have investigated the role of ZtVf1 gene encoding a transcription factor belonging to C2-H2 subfamily. In planta assays revealed that ZtVf1 is required for virulence. Reduced necrotic lesions and low pycnidia density within the lesions resulted in significantly reduced virulence of ZtVf1 mutants. Cytological analysis showed that the impaired virulence of ZtVf1 mutants attributed to reduced penetration and colonization along with hampered pycnidia differentiation. In vitro phenotyping showed that ZtVf1 deletion affects hyphal branching and biomass production suggesting that the reduced tissue colonization by the ZtVf1 mutant might be due to lower hyphal branching and less fungal biomass production. In addition, the majority of infected substomatal cavities by the ZtVf1 mutant filled with compacted mycelia mat that did not differentiate to mature pycnidia indicating that the impaired melanization negatively affected pycnidia formation and maturation. The ZtVf1 might target multiple genes belonging to different cellular processes whose identification is of eminent interest to increase our understanding of this pathosystem. Overall, the data provided in this study indicates that attenuated pathogenicity of ZtVf1 mutant is due to involvement of this gene in the regulation of both early and late stages of infection

Study of defense genes expression profile pattern of wheat in response to infection by Mycosphaerella graminicola

The aim of this study was to examine the effect of salicylic acid on the gene expression pattern of four enzymes; Phenylalanine ammonialyase, Polyphenol oxidase, Peroxidase and Catalase in wheat-Mycosphaerella graminicola pathosystem. For this reason, Salicylic Acid (2mm) were sprayed on wheat in two-leaf stage before inoculation with the fungal pathogen. Sampling of the plants was done at five time points (0, 3, 6, 12 and 24 h) after inoculation. The scanning of genes expression pattern of encoding enzymes were carried out by reverse northern dot blotting method. The results showed that within 24 hours post inoculation the gene expression of these enzymes significantly increased in this tolerant cultivar. SA enhanced the expression of Phenylalanine ammonialyase and Peroxidase genes in all time points. The expression of Polyphenol oxidase was increased by SA after 12h. On the other hand, increasing the expression level of these genes directly increases the activity of the enzymes which indicates direct role of these gens in plant defense system. SA caused a rapid rise in expression of Catalase gene, but this effect was not continued for 24h

Medicinal mushroom Agaricus subrufescens from Iran shares genetic markers with specimens from China and Thailand

Agaricus subrufescens Peck is a cosmopolitan species of nutritional and medicinal interest. Three types of internal transcribed spacer (ITS) rDNA sequences were recently characterized for this species. Sequences of types A, B, or both types A and B are found in American and European specimens, while sequences of type C are found in Asian (China and Thailand) and Oceanian (Hawaii) specimens. We report on a collection of this species from Iran, for the first time. Both the morphological features and ITS sequence confirm its identification as A. subrufescens. Its ITS sequence was of type C and even identical to that of specimens previously reported from Hawaii, China, and Thailand. This sequence differed from those of Europe or the Americas, where most current cultivars originate. The discovery of a specimen likely native to Iran extends the known distribution range of the ITS sequence of type C from East Asia to Iran. More collections from West Asia (and elsewhere, for example Africa) would help to better know the distribution area of the different types of ITS sequences and to increase the available germ-plasm resources of A. subrufescens

MADS-Box Transcription Factor ZtRlm1 Is Responsible for Virulence and Development of the Fungal Wheat Pathogen Zymoseptoria tritici

Zymoseptoria tritici is one of the most economically destructive wheat diseases all over the world and is a model fungal plant pathogen within the ascomycetes. In this study, the instrumental role of the ZtRlm1 gene encoding a MADS-box transcription factor (TF) in the infection process of Z. tritici was functionally characterized as these proteins play critical roles in the global gene regulation required for various developmental and physiological processes. Our infection assays showed that ZtRlm1 mutants were attenuated in disease development as a 30 and 90% reduction in chloro-necrotic lesions and pycnidia formation, respectively, were observed in plants inoculated with ZtRlm1 mutant strains demonstrating that ZtRlm1 is a crucial factor playing a significant role in the late stage of infection corresponding with pycnidial formation. Our expression analysis demonstrated that the transcript level of ZtRlm1 is induced at 2 and 20 days post-inoculation, coinciding with pycnidial sporulation. In addition, microscopic analyses showed that branch intensity and biomass production were significantly reduced, indicating that impaired pycnidia formation is a result of impaired differentiation and biomass production in the ZtRlm1 mutants. Furthermore, melanization, a phenomenon required for fruiting body formation, was significantly hampered in ZtRlm1 mutants as they were not melanized under all tested temperature and media conditions. Overall, our data showed that impaired disease development of the ZtRlm1 mutants is mainly due to the significant impact of ZtRlm1 in different cellular processes, including differentiation, branching, fungal biomass production, and melanization, in which identification of downstream genes are of interest to increase our understanding of this pathosystem