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Rinalducci S.,University of Tuscia | Egidi M.G.,University of Tuscia | Mahfoozi S.,Iranian Seed and Plant Improvement Institute | Jahanbakhsh Godehkahriz S.,University of Mohaghegh | Zolla L.,University of Tuscia
Journal of Proteomics

In this work, proteomics was used to study the influence of both optimal and low temperatures on growth and development in a vernalization-requiring winter wheat (Triticum aestivum L. cv Cheyenne) after prolonged times of treatment. For this purpose, plants were grown at optimal temperature (20°C) for 14days (zero point) after which half were transferred to conditioned chambers kept at 4°C for a period of 63days. Cold tolerance, as estimated from lethal temperatures (LT 50), and phenological development, as measured by final leaf number (FLN) and shoot apex dissection, were determined. Proteomic analysis indicated a down-accumulation of several photosynthesis-related proteins and a concomitant increase in abundance of some Calvin cycle enzymes. A cold-induced accretion of soluble sugars and proline was observed as well. In parallel, an increase of proteolysis accomplished by an up-modulation of TCA cycle enzymes was also noticed, probably suggesting an efficient recycling of amino acids as energy source. Proteomic analysis of plants grown at optimal temperature allowed to specifically discriminate cold-induced proteins and highlight molecular processes driven by vernalization. Among identified proteins typically involved in vernalization responses and floral transition we observed a marked increase of wrab17, wcor18 and glycine-rich RNA-binding proteins. © 2011 Elsevier B.V. Source

Erfani J.,University of Tehran | Ebadi A.,University of Tehran | Abdollahi H.,Iranian Seed and Plant Improvement Institute | Fatahi R.,University of Tehran
Plant Molecular Biology Reporter

The genetic diversity and relationships among 47 pear cultivars and genotypes (Pyrus spp.), including 4 Japanese pears (Pyrus pyrifolia), 40 European pears (Pyrus communis), 1 Chinese pear (Pyrus bretschneideri) as well as 2 wild relatives (Pyrus salicifolia and Pyrus mazandaranica) were studied using 28 microsatellite primer pairs. A total of 174 alleles were produced at the 28 SSR loci with their sizes ranging from 81 to 290 bp. The number of observed alleles for each locus ranged from 3 (TsuENH014 and TsuENH046) to 12 (NB103a), with an average of 6. 21 alleles per locus. In some SSR loci, more than two alleles were amplified in some cultivars and genotypes, suggesting that duplication has occurred in those accessions. This information suggests that at least two genomic regions exist for these loci in the pear genome. The observed heterozygosity (H o) values of amplified loci ranged from 0. 17 (TsuENH006) to 0. 97 (NB103a). Shannon's information index (I) value was observed to be highest (2. 14) in the NB103a locus, while the TsuENH006 locus had the lowest value with an average of 1. 37 among SSR loci. The Dice genetic similarity coefficient ranged from 0. 29 ("Nijisseiki" and P. mazandaranica) to 0. 91 ("Chojuro" and "Nijisseiki") among samples. UPGMA cluster analysis showed two major groups corresponding to the Japanese and European pears. © 2012 Springer-Verlag. Source

Afshari F.,Iranian Seed and Plant Improvement Institute
Archives of Phytopathology and Plant Protection

The wheat stripe (yellow) rust is one of the most important diseases in Iran. In this study, 41 races out of 104 isolates in greenhouse were determined from 2008 to 2010. Races 6E6A+, 6E10A+ and 6E0A+ were more common. Races 0E0A+ was less aggressive than races 166E158A+ and 134E158A+ with virulence on 11 known genes. Virulence on plant/s with gene/s Yr1, Yr2, Yr4, Yr6, Yr7, Yr8, Yr9, Yr10, Yr25, Yr27, YrSU, YrSD, YrND, Yr3, Yr2+, Yr6+, Yr9+, Yr7+, YrCV and YrA was detected. The majority of isolates with high frequency (more than 70%) showed virulence on plant/s with Yr2, Yr7, Yr9 and YrA genes. No virulence was detected on plant/s with Yr3, Yr5 and YrSP. In greenhouse test, frequency of virulence to wheat genotypes with Yr1, Yr4, Yr10, YrCV (32+) and YrSD gene was less than 7%. Frequency of virulence to other wheat genotypes was between 8 and 100%. © 2013 Taylor & Francis. Source

Mehrabi R.,Wageningen University | Mehrabi R.,Iranian Seed and Plant Improvement Institute | Bahkali A.H.,King Saud University | Abd-Elsalam K.A.,King Saud University | And 7 more authors.
FEMS Microbiology Reviews

Plant pathogenic fungi adapt quickly to changing environments including overcoming plant disease resistance genes. This is usually achieved by mutations in single effector genes of the pathogens, enabling them to avoid recognition by the host plant. In addition, horizontal gene transfer (HGT) and horizontal chromosome transfer (HCT) provide a means for pathogens to broaden their host range. Recently, several reports have appeared in the literature on HGT, HCT and hybridization between plant pathogenic fungi that affect their host range, including species of Stagonospora/Pyrenophora, Fusarium and Alternaria. Evidence is given that HGT of the ToxA gene from Stagonospora nodorum to Pyrenophora tritici-repentis enabled the latter fungus to cause a serious disease in wheat. A nonpathogenic Fusarium species can become pathogenic on tomato by HCT of a pathogenicity chromosome from Fusarium oxysporum f.sp lycopersici, a well-known pathogen of tomato. Similarly, Alternaria species can broaden their host range by HCT of a single chromosome carrying a cluster of genes encoding host-specific toxins that enabled them to become pathogenic on new hosts such as apple, Japanese pear, strawberry and tomato, respectively. The mechanisms HGT and HCT and their impact on potential emergence of fungal plant pathogens adapted to new host plants will be discussed. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. Source

Stergiopoulos I.,University of California at Davis | Collemare J.,Wageningen University | Mehrabi R.,Wageningen University | Mehrabi R.,Iranian Seed and Plant Improvement Institute | De Wit P.J.,Wageningen University
FEMS Microbiology Reviews

Many necrotrophic plant pathogenic fungi belonging to the class of Dothideomycetes produce phytotoxic metabolites and peptides that are usually required for pathogenicity. Phytotoxins that affect a broad range of plant species are known as non-host-specific toxins (non-HSTs), whereas HSTs affect only a particular plant species or more often genotypes of that species. For pathogens producing HSTs, pathogenicity and host specificity are largely defined by the ability to produce the toxin, while plant susceptibility is dependent on the presence of the toxin target. Non-HSTs are not the main determinants of pathogenicity but contribute to virulence of the producing pathogen. Dothideomycetes are remarkable for the production of toxins, particularly HSTs because they are the only fungal species known so far to produce them. The synthesis, regulation, and mechanisms of action of the most important HSTs and non-HSTs will be discussed. Studies on the mode of action of HSTs have highlighted the induction of programed cell death (PCD) as an important mechanism. We discuss HST-induced PCD and the plant hypersensitive response upon recognition of avirulence factors that share common pathways. In this respect, although nucleotide-binding-site-leucine-rich repeat types of resistance proteins mediate resistance against biotrophs, they can also contribute to susceptibility toward necrotrophs. This review paper describes host-specific toxins (HSTs) and non-HSTs produced by fungal species belonging to the class of Dothideomycetes. © 2012 Federation of European Microbiological Societies. Source

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