گزارشی از سفیدک‌های پودری (تیره erysiphaceae) استان اردبیل و معرفی چند میزبان‎ جدید برای ایران

قارچ‌های عامل سفیدک‌ پودری متعلّق به تیره erysiphaceae، یکی از گسترده ترین و قابل تشخیص ترین بیماری های گیاهی هستند و خسارت قابل توجهی را به محصولات کشاورزی وارد می کنند. به‎منظور مطالعه این قارچ‌های بیماری‌زا، طی سال‌های 1400 و 1401 نمونه‌هایی از انواع گیاهان زراعی، فضای سبز و درختان میوه و جنگلی در برخی شهرهای استان اردبیل جمع‌آوری و خشک شدند. گیاهان میزبان به کمک متخصص گیاه شناسی و با استفاده از منابع مرتبط با فلور ایران شناسایی گردید. از اندام های مختلف قارچ‌ها از قبیل فرم جنسی یا غیرجنسی، اسلاید میکروسکوپی تهیه شد. با استفاده از میکروسکوپ نوری، مشخصات ریخت شناختی نمونه ها جهت شناسایی قارچ عامل بیماری یادداشت شده و در نهایت به کمک تک نگاشت براون و کوک (2012) و برخی مقالات معتبر، قارچ های عامل سفیدک پودری در حد جنس و گونه مورد شناسایی قرار گرفتند. در این پژوهش، تعداد 33 گونه قارچ عامل سفیدک پودری از هفت جنس مختلف بر روی 46 میزبان گیاهی شناسایی شدند. در بین آرایه‌ها، گونه‌های erysiphe trifoliorum از روی trifolium tumens، golovinomyces orontii species complex از روی fraxinus excelsior و lactuca scarioloides، g. sonchicola از روی sonchus asper، و leveillula taurica از روی vicia sativa برای اولین بار از روی این میزبان‌های جدید از ایران گزارش می شوند. هم چنین گزارش 11 گونه شامل e. capreae، e. prunastri، e. trifoliorum، e. ulmi var. ulmi، g. cichoracearum، g. orontii، l. chrozophorae، l. taurica، podosphaera euphorbiae، p. fusca و p. plantaginis از روی 14 میزبان برای میکوفلور استان اردبیل جدید می‌باشد. جنس‌های erysiphe و podosphaera به‌ترتیب با 13 و نه گونه، دارای بیشترین فراوانی بودند.

a report on powdery mildew fungi (erysiphaceae) of ardabil province and introduction of some new hosts for iran

introductionpowdery mildews belong to the order erysiphales, class leotiomycetes, and phylum ascomycota. these fungi belong to the family erysiphaceae and cause a fungal disease called powdery mildew in various host plants. the symptoms of powdery mildew are mostly seen as spots or a layer of white, yellow, brown, or gray mycelium (conidiophores) or spherical sexual structures with yellow, brown to black color (chasmothecium). as obligate biotrophs, powdery mildew fungi obtain their nutrients from living cells of their host plants through specialized feeding organs known as the haustoria. the host range of this group of fungi is limited to angiosperms, and no powdery mildew is known to occur on gymnosperms. the life cycle of most members of the erysiphaceae family consists of both sexual and asexual stages, and only in a few genera, the asexual stage is not known. the infection usually starts rapidly with conidia on the leaf surface. the conidia of powdery mildew fungi are transferred by wind from infected hosts to other plants and to initiate infection, they germinate on the budding leaves of plants and form appressorium, leading to the formation of haustorium. with more than 7500 plant species and a diverse climate, iran harbors many plant pathogenic fungal species, including powdery mildew causing fungi. according to the available literature, about 33 species belonging to nine genera, which cause powdery mildew, have been identified and described from ardabil province. as we know, the major use of land in ardabil province is for agriculture and pasture. for this reason, fungi belonging to the erysiphaceae family are important and diverse in this province. due to limited studies in this area, the fungi causing powdery mildew disease on various plants in some cities of ardabil province including ardabil, parsabad, khalkhal, sarein, meshginshahr, namin and nir were investigated and identified in the present study.materials and methodsto study powdery mildew fungi, samples of various crops, landscapes, fruit trees, and forests were collected from some cities of ardabil province during the years 2021 and 2022. each sample was given a unique code corresponding to the host. the plant samples were identified with helping of a botanist and using literature related to the flora of iran. microscopic slides were prepared from different structures of fungi such as sexual and asexual forms. morphological characteristics of the samples were measured and recorded to identify the fungus causing the disease via microscopic analyses using an optical microscope. in the case of fresh fungal samples, conidia germination was investigated according to the method described by cook and braun (2009). finally, powdery mildew species were identified using braun and cook’s (2012) monograph and related literature at the level of genus and species. in addition, microscopic color photos were prepared with helping of a digital camera connected to a zeiss optical microscope.results and discussionin recent years in iran and compared to other important groups of fungi, articles related to fungi have been significant and are increasing more or less. some recent publications include lists of powdery mildew causing fungi from iran, but they are often incomplete and limited to regional studies (khodaparast et al., 2002; tavanaei et al., 2005; pirnia et al., 2007). in the past, according to the research conducted in ardabil province, until today, about 32 species belonging to 9 genera powdery mildew causing fungi have been identified and described (davari et al., 2015). in this research, seven genera and 33 species including erysiphe (13 species), golovinomyces (4 species), leveillula (3 species), neoerysiphe (1 species), phyllactinia (2 species), podosphaera (9 species) and sawadaea (one species) were identified from the erysiphaceae.