A Global Survey of Puccinia-Rust on Cucurbitaceae
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Research Collection Journal Article A global survey of Puccinia-rust on Cucurbitaceae Author(s): Berndt, Reinhard Publication Date: 2007 Permanent Link: https://doi.org/10.3929/ethz-b-000006504 Originally published in: Mycological Progress 6(3), http://doi.org/10.1007/s11557-007-0535-z Rights / License: In Copyright - Non-Commercial Use Permitted This page was generated automatically upon download from the ETH Zurich Research Collection. For more information please consult the Terms of use. ETH Library Mycol Progress (2007) 6:151–178 DOI 10.1007/s11557-007-0535-z ORIGINAL ARTICLE A global survey of Puccinia-rust on Cucurbitaceae Reinhard Berndt Received: 14 February 2007 /Revised: 11 May 2007 /Accepted: 11 May 2007 /Published online: 26 June 2007 # German Mycological Society and Springer-Verlag 2007 Abstract In this paper, all known autoecious Puccinia cultivated for their edible fruits. Prominent genera with species (rust fungi, Uredinales) on Cucurbitaceae are de- several economically important crops are Citrullus (melon), scribed and most of them illustrated. A key and information Cucumis (cucumber), Cucurbita (squash and pumpkin) and on their host range and distribution is presented. Four spe- Sechium (chayote). The cucurbits of the Old World are cies, Puccinia antennata, P. arbor-miraculensis, P. hi- especially diverse, comprising several genera and species eroglyphica, and P. rhytidioderma are proposed as new. that are already cultivated or are potential sources and P. momordicae and P. trochomeriae are recognised as valid reservoirs for breeding of new crop and medicinal plants or species different from P. cephalandrae. Uredo melothriae is to improve existing cultivars (Bates et al. 1990). a new combination for Uromyces melothriae. P. cucumeris Among the important fungal pathogens that attack cultivat- is a new report for Namibia, P. momordicae for Zimbabwe ed cucurbits are powdery and downy mildews, Alternaria, and P. vanderystii for Kenya. The species appear to be Fusarium and Verticillium spp. and Colletotrichum lagenarium host specific with regard to host tribes, but P. citrulli and (Pass.) Ellis and Halst. (Blancard et al. 1994;Robinsonand P. cucumeris may pass tribal boundaries. Most species are Decker-Walters 1999). Additionally, cucurbits are attacked morphologically very similar and are characterised by a by rust fungi (Uredinales, basidiomycetes) of the teleomorph unique set of teliospore characters. They are therefore genera Cerotelium, Chrysocelis, Coleosporium, Puccinia and regarded as a natural group. The distribution of this group Uromyces. Most of the latter do not seem to cause damage in semiarid habitats, mainly from southern Africa to India, on cultivated cucurbits and they are not mentioned as pests is discussed. in the manuals of Blancard et al. (1994), Robinson and Decker-Walters (1999) and Zitter et al. (1996). However, the genus Puccinia comprises 18 known species that infect wild Introduction and cultivated species of many cucurbit genera of the Old World and may therefore be potentially harmful (Rizvi and Cucurbitaceae are a medium sized, predominantly tropical Hasanain 1960). to subtropical, plant family with many members that are Most of these Puccinia species are morphologically similar. Where known, they are autoecious, have Caeoma- or Aecidium-like aecia, the latter often with rudimentary Taxonomic novelties peridia, uredinia of Uredium type and, generally, teliospores New species: Puccinia antennata R. Berndt and A. Rössel, P. with a more or less conspicuously bilaminate cell wall. A arbor-miraculensis R. Berndt, P. hieroglyphica R. Berndt, P. remarkable, though often overlooked, feature of several rhytidioderma R. Berndt species is the presence of two (to three) germ pores per New combination: Uredo melothriae (Henn.) R. Berndt for Uromyces teliospore cell. Several mycologists have noted that the latter melothriae Henn. teliospore characters are more typical for members of the R. Berndt (*) genus Uropyxis (Uropyxidaceae) than for Puccinia (Baxter Institute of Integrative Biology, ETH Zurich, 1959): Ito and Murayama (1943)combinedP. arisanensis to Herbarium turicense, 8092 Zurich, Switzerland Uropyxis arisanensis, and Ramakrishnan et al. (1952)men- e-mail: [email protected] tioned that P. gymnopetali-wightii was similar to Uropyxis 152 Mycol Progress (2007) 6:151–178 because of the layered cell wall of the teliospores. Ramachar Results et al. (1985)reportedUropyxis-like teliospores with two, rarely three, germ pores per cell in P. ctenolepidis from India. All species are listed in alphabetical order and described in The species revealed spermogonia of type 4, however, detail. Their validity and status are discussed briefly following indicative of Pucciniaceae, not Uropyxidaceae, which have the descriptions. The study resulted in the recognition of the spermogonia of type 5 (Cummins and Hiratsuka 2003). As new species P. antennata, P. arbor-miraculensis, P. hiero- the morphology of spermogonia has proven to be a reliable glyphica,andP. rh yt id io de rm a. marker for higher-level relationships among rust fungi, it is reasonable to accommodate these rust fungi with Puccinia Puccinia antennata R. Berndt and A. Rössel, sp. nov. according to morphology of spermogonia rather than teliospore traits. Another character that corroborates this Etymology: denominating the long apiculi of the teliospores affiliation is the presence of Aecidium-like aecia in some (Figs. 1, 2, 3 and 4). species—although the aecial peridium is generally vestigial Aecia in gregibus parvis, dense constipatis, foliicola, amphi- or almost lacking. Members of Uropyxidaceae possess gena sed praecipue abaxialia, bullata, irregulariter cupulato- Uredium-like aecia (Cummins and Hiratsuka 2003). aperta, sine peridio, copia sporarum pallide cinnamomea; The attempt to determine a Puccinia on Cucurbitaceae aeciosporae ellipsoideae, late ellipsoideae, subglobosae, saepe may confront the investigator with unexpected problems: subangulariter obovoideae, nonnunquam apicaliter paulum some species are deceptively similar with regard to certain elongatae et subapiculatae, 21–28(32)×(16)18–23 μm(medi- spore stages and have not always been adequately charac- um 24.5×19.9 μm), pariete ca. 1–1.5 μm crasso, apicaliter terised by the original descriptions. Additionally, quite leniter incrassato usque ad 3 μm (usque ad 6 μminsporis often the descriptions do not comprise the holomorph but subapiculatis), subhyalino ad ochraceo, delicate denseque only single spore stages. Taken together, the morphological similarity of the fungi and the incompleteness of the descriptions may lead—and has led—to misidentifications and erroneous synonymy that hamper our understanding of the biology of this group of fungi. The present study intends to portray all known autoe- cious Puccinia spp. on Cucurbitaceae and to facilitate their identification. It gives an account of the known fungus–host relationships and summarises present knowledge of the geographic distribution of the species. Materials and methods All descriptions are based on dried herbarium specimens. Spore scrapes were mounted in lactophenol and gently heated to boiling. The preparations were examined with a Carl Zeiss “Axiophot” light microscope using DIC optics, and photographs were taken with a Zeiss MC-80 camera on Kodak Ektachrome 64 Professional slide film. Freehand line drawings were prepared combining the observed characters. Details of the spore surface and layering of the spore wall are shown only in some of the depicted spores. At least 30 spores were measured for each spore stage; exceptions are mentioned in the text. Measurements comprise the usual range and the arithmetic means; extremes are given in brackets. The names of herbaria are abbreviated by their acronyms according to Index Herbariorum (Stafleu et al. 1981). The Roman numerals 0, I, II, III are used in “Material ” Fig. 1 Puccinia antennata (type), teliospores. The surface ornament studied to designate the spore stages spermogonia, aecia, illustrated on a single spore represents types of warts found on uredinia or telia, respectively. different spores. Bar 20 μm Mycol Progress (2007) 6:151–178 153 ordinary peridium lacking, spore mass pallid cinnamon; aeciospores ellipsoidal, broadly ellipsoidal, subglobose, often slightly angular obovate, sometimes apically slightly elongated and subapiculate, 21–28(32)×(16)18–23 μm (mean 24.5×19.9 μm), spore wall ca. 1–1.5 μmthick,api- cally generally slightly thickened to 3 μm, or—in subapicu- late spores—up to 6 μm, subhyaline to ochraceous, densely verruculose by delicate, slenderly cylindrical warts to ca. 0.5 μm long, germ pores obscure, most probably scattered. Uredinia amphigenous, predominantly abaxial, 0.3–1mm diam., deeply ferrugineous, pulverulent; urediniospores (broadly) ellipsoidal, obovoidal (to subglobose), 23–29×19– 23 μm (mean 26.6×20.8 μm), spore wall 1.5–2 μmthick, ferrugineous, finely and evenly echinulate except for two indistinct smooth patches around the germ pores, ca. (1.5)2– 3 μm between spines, with 2(3) equatorial, more or less opposite germ pores provided with small, inconspicuous papillae. Telia amphigenous, 0.3–1 mm diam. or larger by confluence, black, pulverulent; teliospores mostly broadly ellipsoidal, rarely ellipsoidal or subglobose, rounded at both ends, not or hardly constricted at the septum or even slightly inflated, 34–44(48)×26–32 μm (mean 37.9×28.6 μm), spore wall indistinctly bilaminate, ca. 4 μmthick,upto8μmover germ pores by swollen