Genetic Diversity and Host Range of Powdery Mildews on Papaveraceae
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Mycol Progress (2016) 15: 36 DOI 10.1007/s11557-016-1178-8 ORIGINAL ARTICLE Genetic diversity and host range of powdery mildews on Papaveraceae Katarína Pastirčáková1 & Tünde Jankovics2 & Judit Komáromi3 & Alexandra Pintye2 & Martin Pastirčák4 Received: 29 September 2015 /Revised: 19 February 2016 /Accepted: 23 February 2016 /Published online: 10 March 2016 # German Mycological Society and Springer-Verlag Berlin Heidelberg 2016 Abstract Because of the strong morphological similarity of of papaveraceous hosts. Although E. macleayae occurred nat- the powdery mildew fungi that infect papaveraceous hosts, a urally on Macleaya cordata, Macleaya microcarpa, M. total of 39 samples were studied to reveal the phylogeny and cambrica,andChelidonium majus only, our inoculation tests host range of these fungi. ITS and 28S sequence analyses revealed that the fungus was capable of infecting Argemone revealed that the isolates identified earlier as Erysiphe grandiflora, Glaucium corniculatum, Papaver rhoeas, and cruciferarum on papaveraceous hosts represent distinct line- Papaver somniferum, indicating that these plant species may ages and differ from that of E. cruciferarum sensu stricto on also be taken into account as potential hosts. Erysiphe brassicaceous hosts. The taxonomic status of the anamorph cruciferarum originating from P. somniferum was not able to infecting Eschscholzia californica was revised, and therefore, infect A. grandiflora, C. majus, E. californica, M. cordata, a new species name, Erysiphe eschscholziae, is proposed. The and P. rhoeas. The emergence of E. macleayae on M. taxonomic position of the Pseudoidium anamorphs infecting microcarpa is reported here for the first time from the Glaucium flavum, Meconopsis cambrica, Papaver dubium, Czech Republic and Slovakia. The appearance of chasmothecia and Stylophorum diphyllum remain unclear. This study re- of E. macleayae on C. majus in Slovakia was reported, as well. vealed that Erysiphe macleayae exhibits a specific host range Erysiphe cruciferarum was identified on G. corniculatum and different from that of E. cruciferarum, the common pathogen reported here for the first time from Slovakia. Keywords Erysiphaceae . Eschscholzia . Macleaya . ITS . Section Editor: Franz Oberwinkler 28S nrDNA . Morphology Taxonomic novelty Erysiphe eschscholziae Pastirč. & Jankovics Katarína Pastirčáková and Tünde Jankovics contributed equally to this work. Introduction * Katarína Pastirčáková Asexual morphs of powdery mildews belonging to the same [email protected] genus are, in many cases, morphologically indistinguishable from each other. Therefore, their identification is often com- plicated, especially in the absence of the sexual morphs 1 Institute of Forest Ecology, Branch for Woody Plant Biology, Slovak Academy of Sciences, Akademicka 2, SK-94901 Nitra, Slovakia (chasmothecia), and sometimes questionable based exclusive- ly on morphological data. The identification might be more 2 Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, P.O. Box 102, problematic in those particular cases when one host plant spe- H-1525 Budapest, Hungary cies is infected by more than one asexual powdery mildew 3 Agricultural Institute, Centre for Agricultural Research, Hungarian fungi with highly similar morphologies (Cook et al. 1997). Academy of Sciences, Brunszvik u. 2, On the other hand, morphologically indistinguishable asexual H-2462 Martonvásár, Hungary morphs may represent genetically distinct lineages that seem 4 Research Institute of Plant Production, National Agricultural and to be specialized to one or a few host plant species belonging Food Centre, Bratislavska cesta 122, SK-92168 Piestany, Slovakia even to different plant families. Recently, phylogenetic 36 Page 2 of 18 Mycol Progress (2016) 15: 36 relationships among various closely related powdery mildew this study were (i) to investigate the phylogenetic relationships species have been revealed based on the nucleotide sequences and taxonomic positions of the powdery mildew pathogens of the internal transcribed spacer (ITS) and 28S regions of occurring naturally on papaveraceous hosts and exhibiting nuclear ribosomal DNA (nrDNA) (e.g. Cunnington et al. morphologically indistinguishable asexual morphs of the 2005; Kiss et al. 2006; Inuma et al. 2007; Jankovics et al. Pseudoidium type, based on the nucleotide sequences of the 2008; Takamatsu et al. 2008, 2013). ITS and 28S nrDNA regions; and (ii) to determine whether the To date, three Erysiphe species exhibiting asexual two powdery mildew species E. cruciferarum and E. Pseudoidium stages have been reported from the family macleayae, both of which occur on hosts native to Europe, Papaveraceae, namely Erysiphe cruciferarum Opiz ex L. can infect papaveraceous plant species other than their origi- Junell, E. hylomeci H.D. Shin & Y.J. La, and E. macleayae nal hosts. R.Y. Zheng & G.Q. Chen (Braun and Cook 2012). Erysiphe cruciferarum is the most common causal agent of the powdery mildew on various papaveraceous hosts in Asia and Europe (Braun 1987; Braun and Cook 2012), while E. hylomeci was Materials and methods recorded only on Hylomecon vernalis in Korea (Shin 2000), and E. macleayae haslongbeenconsideredtobeendemicto Fungal material and morphological observations Asia (Park et al. 2012). Recently, asexual powdery mildew morphs identified as E. macleayae have been reported to oc- In order to find fruiting bodies of the powdery mildew patho- cur on Macleaya cordata in Germany (Ale-Agha et al. 2008; gen infecting C. majus, diseased leaves of this host were col- Schmidt and Scholler 2011)andMacleaya microcarpa in lected in Slovakia and Hungary, where the fungus is known to Poland and Ukraine (Park et al. 2012; Heluta and Kravchuk occur only in its asexual stage. For the precise identification of 2015). In Germany, the asexual morph of this species has been the fungus causing symptoms on Glaucium corniculatum,the observed on Chelidonium majus as BOidium sp.^ since 2003 powdery mildew infected leaves and seed pods of this plant (Jage et al. 2010), while both the asexual and sexual morphs species were also collected in Slovakia in 2013. The speci- were found to be present on a new host, Meconopsis cambrica mens were examined using a stereo binocular microscope (Schmidt and Scholler 2011). Since the first record of pow- (SZ61, Olympus, Japan) and a standard light microscope dery mildew infection on C. majus in Italy (Ciferri and (BX51, Olympus, Japan). Fresh powdery mildew mycelium Camera 1962), only Oidium/Pseudoidium sp. has been iden- was scraped off the leaves and mounted in distilled water for tified on this host in several European countries until recently morphological characterization and measurements using oil (Pastirčáková and Pastirčák 2013; Heluta and Kravchuk immersion at 1000× magnification. The morphological struc- 2015). In 2014, chasmothecia have been collected on C. majus tures of the fungi were photographed using a digital camera in Germany several times by H. Jage and were distributed as (SP350, Olympus, Japan). Representative specimens of the U. Braun, Fungi selecti exsiccati 213 (Braun 2014). In Asia, a new collections were deposited in the herbarium NR. A du- powdery mildew, indistinguishable from the one occurring in plicate of the specimen of E. macleayae on C. majus Europe and identified as either E. cruciferarum or Oidium sp., (with mature chasmothecia) from Slovakia was deposit- hasbeenreportedtooccuronChelidonium spp. in the Russian ed at BPI, as well. Far East (Bunkina 1991), Japan (Nomura 1997), and South In order to re-examine the powdery mildew fungi collected Korea (Shin 2000). Recently, Jiang et al. (2015)havefound previously from various papaveraceous hosts, 29 herbarium chasmothecia on C. majus in China and identified the causal specimens were borrowed from G, HMAS, KR, and SOMF agent as E. macleayae confirmed by morphological and (abbreviations of herbaria according to Thiers [continuously molecular analyses. However, although the above men- updated]). The specimens from Japan and Romania were pro- tioned European records suggest the recent emergence vided by S. Takamatsu (Mie University, Tsu, Japan) and V. of E. macleayae in Europe, exhaustive attempts to iden- Iacob (University of Applied Life Sciences and Environment, tify these primarily asexual powdery mildew morphs Iasi, Romania), respectively. The herbarium specimens repre- have not been made so far, particularly by means of sented powdery mildew fungi occurring naturally on 13 dif- molecular approaches. ferent host plant species, i.e. C. majus, Eschscholzia Because of their morphological similarity, as well as the californica, G. corniculatum, G. flavum, M. cordata, M. close affinities of their host species, many powdery mildews cambrica, Papaver aurantiacum, P. croceum, P. dubium, P. on papaveraceous hosts have been assigned to E. nudicaule, P. rhoeas, P. somniferum,andStylophorum cruciferarum or Oidium sp./Pseudoidium sp. Such powdery diphyllum. Herbarium specimens of E. cruciferarum on type mildew species might easily be misidentified, above all when host Alyssum spp. (Brassicaceae) were borrowed from PRM only morphological patterns and hosts are considered; there- and SAV. The lactic acid technique (Shin and La 1993)was fore, a more complex approach is required. The objectives of used for microscopic examination of herbarium material. Mycol Progress (2016) 15: 36 Page 3 of 18 36 DNA extraction, PCR amplification, and sequencing Foster City, CA) according