MYCOLOGIA IRANICA
Year:2017 | Volume:4 | Issue:2 |Papers Count:7

The genus Libertella Desm is a member of Diatrypaceae family in the order of Xylariales (Smith et al. 2003). Libertella has often been reported in various vascular plants (Kirk et al. 2001). During December 2017, Libertella isolates were recovered from the trunk of plane trees (Platanus orientalis), showing decline symptoms in Kermanshah urban area.

Brown rot symptoms were observed on Chamaecyparis shrubs planted in the green landscape of Gorgan region, Golestan province (36° 30′ 38° ″ N, 53° 57′ 56° ″ E), as twig dieback during January 2015. More than 20% of the trees were observed with disease symptoms. Initial symptoms were brown lesions on the leaves.

flatoxins are highly toxic compounds that are produced as secondary metabolites by some Aspergillus and Emericella species. Despite huge progress on aflatoxin research during the past 50 years, we have witnessed many cases of food contamination with aflatoxins all over the world. Aflatoxins have mutagenic and carcinogenic effects and they are capable of inducing hepatocellular carcinoma in human and animals. A wide array of substrates including nuts, oilseeds, cereals and dried fruits are susceptible to aflatoxin contamination which is a challenge for public health, especially in developing countries. Improper storage of food and feed provides conditions for aflatoxin production in crops, especially rice, wheat, pistachio, walnuts, and almonds which are the main sources of nutrients in the human food chain. Aflatoxins can be found in animal tissues and milk after ingestion of contami-nated feed. Among nuts, pistachio is one of the most important exporting products of Iran which its contamination with aflatoxins is frequently reported. In general, despite frequent reports of aflatoxin– producing fungi and aflatoxin contamination of food and feed in Iran, limited data exist about human and animal exposure to aflatoxins and related consequ-ences. This review highlights current status and future prospects of aflatoxin occurrence in food, feed and agricultural commodities in Iran, adverse effects on public health, advanced assay procedures and current control measures of aflatoxin contamination.

In spite of the economic importance of powdery mildew on cucurbits, literature and databases about the fungal species reveal different species numbers and names, often indicating only two species, with inconsistent host specificities for different members of Cucurbitaceae. Revision of the available literature indicates the presence of at least six species of powdery mildews on Cucurbitaceae with different focuses on hosts and geographic distribution. Golovinomyces orontii is recorded from Cucurbitaceae in Taiwan for the first time based on internal transcribed spacer sequences and the morphology of the anamorph found on wild plants of Coccinia grandis. In the literature; although, winter melon (Benincasa hispida) is considered resistant against Podosphaera xanthii, we confirmed a previously doubtful record on this host in Taiwan. Our new records of G. orontii in wild cucurbits and of P. xanthii for winter melon indicate a higher potential threat against cultivated cucurbits than previously estimated.

Chickpea (Cicer arietinum L. ) is one of the most important legume crops in Iran. Wilt disease caused by Fusarium oxysporum f. sp. ciceri, is the most important soil-borne disease of chickpea in the world. This disease caused high losses in different regions during recent years. Simple sequence repeat (SSR) were used to estimate genetic diversity in 114 of F. oxysporum isolates from six counties in the western of Iran (Asemanabad, Sarableh, Eivan, Badreh, Chardavol and Dareh Shahr). A set of five microsatellite primer pairs revealed 17 alleles in each locus across the populations. A low level of genetic variability was observed among isolates in these regions. Genetic diversity was low (H = 0. 269) within populations with corresponding high average gene flow and low genetic distances between populations. The smallest genetic distance was observed between isolates from Chardavol and Darahshahr regions. Effective number of alleles was higher in Asemanabad in comparison to the other populations. The number of (H) and Shannon's Information index (I) were also higher in Badreh (H = 0. 430, I = 0. 281). The total gene diversity and gene diversities between subpopulation were estimated 0. 2004 and 0. 188, respectively. Gene diversity attributable to differenti-ation among populations was 0. 0618, while gene flow was 7. 589. Cluster analysis based on UPGMA showed the lowest genetic distance between Chardavol and Dareh Shahr, then between Chardavol and Badreh. The dendrogram indicated a clear break between Asemanabad and the remaining populations. These results will be useful in breeding for chickpea root rot resistant cultivars and developing necessary control measures.

Fungal spores are continuously deposited on the leaf surfaces by wind impaction, sedimentation and rain wash– out from the atmosphere and splash– dispersal. They reside and act as asymptomatic mutualists, benign commensals or latent pathogens. A slight imbalance in this relation can lead to a pathogenic phase of the fungi, resulting in a variety of symptoms on leaves viz. discoloration, blight, sooty– spots, shot– hole, tar spot, powdery mildew, black mildews, downy mildews, rust, smuts, galls, sooty moulds and so on. With a view of studying the foliicolous fungi, a project entitled “ Foliicolous fungi of Maharashtra” was undertaken and various areas were visited in different forest ecosystems of Maharashtra. A total of 429 isolates belonging 336 fungal species and intra specific taxa recorded during this study were categorized on the basis of foliage symptoms caused by them. Out of the entire recorded fungal taxa, 19. 81% fungal species cause black mildews; 5. 83% fungal species belong to only cercosporoid fungi causing leaf spots; 2. 10% fungal species incite powdery mildews; 10. 96% cause sooty molds; 1. 63% incite anthracnose; 0. 23% incite leaf smut; 3. 50% incite leaf rust infection; 19. 35 % incite leaf spots; 11. 42% cause leaf blight/canker; 0. 47% fungal species incite tar spots; 1. 86% incite wilt diseases and the remaining 22. 84% were found to be associated with leaves as facultative parasites/ saprophytes/Hyperparasites. Therefore, above studies were designed to characterize foliicolous fungi that would further help in the conservation and management of biological resources and also increase the agriculture wealth of the nation.

Field surveys in Zagros forests located in western Iran were done to study some aspects of biology and host range of Biscogniauxia mediterranea during 2014-2016. The ability of its conidia and ascospores to cause the disease was evaluated under greenhouse condition. Ascospore viability and development of anamorph and teleomorph were surveyed under different conditions. The pathogen host range was determined by field observations, laboratory and greenhouse tests. Results showed that ascospores unlike conidia produced colony and caused disease by inoculation into the lesion in Quercus brantii seedlings. Ascospore germination was decreased as much as 17. 3% under forest conditions after one year. Extent necrosis in the inner bark and wood tissues of inoculated adult Q. brantii trees was induced however no fungal stroma has appeared for three years. Monopartite black stroma lacking teleomorph was formed beneath the outer bark of inoculated excised branches on which conidia were produced. Teleomorph was formed only on one Q. infectoria excised branch under natural-like condition. Teleomorph and anamorph have not produced on inoculated Q. brantii, Q. infectoria and Q. libani seedlings for 34 months. In the forest, the sign of charcoal disease was seen only on Q. brantii and Q. infectoria trees that the latter is a new host for it. Necrosis appeared in the inner bark of inoculated excised branches of Amygdalus sp. Acer monspessulanum, Cerasus microcarpa, Pistacia sp. and Rosa sp. but not in Crataegus sp. and Ulmus sp. Pathogenicity of B. mediterranea was demonstrated for the first time on seedlings of Q. infectoria and Q. libani.