See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/322908252 The Genus Periglandula and Its Symbiotum with Morning Glory Plants (Convolvulaceae) Chapter · February 2018 DOI: 10.1007/978-3-319-71740-1_5 CITATIONS READS 4 555 2 authors, including: Eckhard Walter Leistner, My name is not Leister!!!!!!!!! University of Bonn 220 PUBLICATIONS 3,333 CITATIONS SEE PROFILE Some of the authors of this publication are also working on these related projects: Dear Suvarna, I am retired since 10 years. I cannot do any research anymore. I am reading a little bit and write reviews some time. Best wishes Eckhard Leistner View project Ginkgo biloba View project All content following this page was uploaded by Eckhard Walter Leistner, My name is not Leister!!!!!!!!! on 23 March 2018. The user has requested enhancement of the downloaded file. The Genus Periglandula and Its Symbiotum with Morning Glory Plants (Convolvulaceae) 1 2 E. LEISTNER ,U.STEINER CONTENTS characteristic of a limited amount of microbial or I. The Ecological Role of Natural plant taxa, e.g., an order, a family, a species, or Products ..................................... 131 even a subspecies only. Many of the natural pro- II. The Symbiosis Between Poaceae and ducts exhibit physiological activities which is the Clavicipitaceous Fungi ....................... 132 basis for their use in medical applications III. Epibiotic Clavicipitaceous Fungi Associated with Convolvulaceae ......................... 133 (Clardy and Walsh 2004). A. Identification of Genus Periglandula ...... 133 The high physiological activities of many 1. Microscopic and Electron Microscopic natural products had triggered a now historical Characterization ........................ 133 dispute about the role of natural products in the 2. Phylogenetic Trees and Taxonomy . 136 producing organism. It was proposed that “the B. Seed Transmittance of Epibiotic Fungi Colonizing Convolvulaceae . ............... 137 multiplicity of natural products is caused by ran- C. Plant Growth Under Germfree Conditions 139 dom processes of mutations, i.e. it reflects the D. Biosynthesis and Accumulation of Ergot gambling of nature rather than a sophisticated Alkaloids in the Fungus/Plant strategy” (Mothes 1981;Mothesetal.1985). Symbiotum . ............................ 141 This hypothesis, however, neglects the pos- E. Periglandula and the Evolution of the Ergot Biosynthetic Pathways . ................... 142 sibility that mutations may turn out to be det- IV. Additional Fungus/Plant Symbiota in rimental or advantageous to the mutated Dicotyledonous Plants ....................... 143 organism. In the former case, a mutated organ- V. Conclusions ................................. 144 ism may be eliminated or in the latter case References . ................................ 145 benefit from an increased fitness and a better chance to survive in a certain ecological setting (Zenk 1967). Today the ecological role of natu- I. The Ecological Role of Natural ral products is well accepted in the scientific Products community (Harborne 2004; Eisner 2003; White Jr et al. 2003). Natural product research entered a new era Microorganisms and plants have one thing in when it was discovered that plants and fungi common: both are frequently equipped with an elaborated during evolution, another way to elaborate biosynthetic machinery responsible for acquire natural products. They may not only the formation of an almost unlimited variety of be formed in biosynthetic processes by one natural products. Typically, natural products— particular organism itself, but instead, a host which are also called secondary metabolites—are organism may harbor a natural product-pro- ducing microorganism: A plant may be asso- 1 Institut fu¨r Pharmazeutische Biologie, Rheinische Friedrich ciated with a bacterium (Piel 2004; Strobel et al. Wilhelm-Universita¨t Bonn, Bonn, Germany; e-mail: eleist- 2004; Gunatilaka 2006) or a fungus (Strobel et [email protected] 2 Institut fu¨r Nutzpflanzenwissenschaften und Ressour- al. 2004; Gunatilaka 2006), while a fungus may censchutz (INRES), Rheinische Friedrich Wilhelm-Universita¨t harbor a bacterium (Partida-Martinez and Bonn, Bonn, Germany; e-mail: [email protected] Hertweck 2005). Physiology and Genetics, 2nd Edition The Mycota XV T. Anke, A. Schu¨ffler (Eds.) © Springer International Publishing AG 2018 132 E. Leistner and U. Steiner In such associations both organisms may Steiner et al. 2006; Ahimsa-Mueller et al. 2007; form a symbiotum in which the associated Markert et al. 2008; Steiner et al. 2008, 2011; microorganism benefits by receiving nutrients, Beaulieu et al. 2015). This indicates that ergot protection, reproduction, and dissemination, alkaloids are components in a fungus/plant whereas the host takes advantage of physiolog- symbiotum characterized by mutual defense ically active compounds which may promote and interaction which constitutes a driving plant growth, herbivore deterrence, and/or force for evolutionary processes (Saikkonen et increased fitness (Arnold et al. 2003; White Jr al. 2015, Schardl et al. 2013). et al. 2003; Saikkonen et al. 2004). Symbiota and their contained natural pro- ducts play a decisive role in evolution as all species evolve in interactions with other species II. The Symbiosis Between Poaceae and (Saikkonen et al. 2015). A point in case is the Clavicipitaceous Fungi beneficial activity of ergot (syn. ergoline) alka- loids which are products of clavicipitaceous A rather well-investigated experimental system fungi colonizing monocotyledonous plants consists of clavicipitaceous fungi colonizing like Poaceae, Juncaceae, and Cyperaceae (Clay Juncaceae, Cyperaceae, and Poaceae plants. In and Schardl 2002; White Jr et al. 2003; Schardl these symbiota ergoline alkaloids play an et al. 2006). Ergot alkaloids, however, are also important role (Keller and Tudzynski 2002). present in higher dicotyledonous plants of the The symbiotic fungi belong either to the tribe family Convolvulaceae (Hofmann 1961, 2006). Clavicipeae or Balanseae within the family This disjointed occurrence of a group of natural Clavicipitaceae (Bacon and Lyons 2005). The products in evolutionarily unrelated taxa (fungi morphological associations of the fungi with and Convolvulaceae plants) seemed to contra- grasses occur either epicuticular, epibiotic, or dict the generally accepted principle of chemo- endophytic (Bacon and Lyons 2005). In epi- taxonomy that similar or even identical natural phytic growth the fungal mycelium is concen- products are present in related taxa. It was trated on the surface of young leaves, buds, therefore assumed that during evolution, a hor- meristematic regions, and reproductive struc- izontal transfer of genes responsible for ergo- tures (Clay and Schardl 2002). The association line alkaloid biosynthesis might have occurred between fungi and their plant hosts is likely to from fungi to higher plants (Groeger and Floss be an example of host-symbiont codivergence 1998; Tudzynski et al. 2001; Clay and Schardl (Schardl et al. 2008). 2002). Alternatively, it was discussed that ergo- The fungus may be asexual belonging to the line alkaloid biosynthesis was repeatedly group of fungi imperfecti and shows a sexual invented during evolution (Mothes et al. lifestyle or switch between sexual and asexual 1985). In a recent review in this series, Keller propagation. In the sexual lifestyle, fungi para- and Tudzinsky (2002) dealt with the pharmaco- sitize a wide range of grasses where they form logical aspects, biochemistry, genetics, and bio- infections of single grass florets and replace the technology of ergot alkaloids in fungi seed with individual sclerotia (Clay and Schardl associated with Poaceae. We show in the pres- 2002). ent review that neither the horizontal transfer The asexual fungi are vertically transmitted of genes encoding the ergot alkaloid biosynthe- through seeds. They have never been known to sis nor the repeated invention of a rather com- produce infectious spores and rely entirely on plicated biosynthetic pathway took place seed transmission. Especially the asexual fungi during evolution but rather that clavicipitac- exhibit high host specificity. Most interesting, eous fungi not only live on different grasses sexual and asexual fungi may interact in para- but also colonize dicotyledonous plants of the sexual processes contributing to a high diversity family Convolvulaceae (Kucht et al. 2004; of fungal asexual endophytes (Tsai et al. 1994). The Genus Periglandula and Its Symbiotum with Morning Glory Plants (Convolvulaceae) 133 In general, grasses are poor producers of III. Epibiotic Clavicipitaceous Fungi natural products that assist other plants in their Associated with Convolvulaceae long-term strategy to gain an ecological advan- tage. Grasses, however, have the ability to com- A. Identification of Genus Periglandula pensate for this deficiency by acquiring fungi notorious for their poisonous natural products. 1. Microscopic and Electron Microscopic In some cases fungi can be considered the live- Characterization stock of grasses. Fungi associated with plants may produce The infestation of the clavicipitaceous fungi on different classes of alkaloids among which toxic Ipomoea asarifolia and Turbina corymbosa, ergot alkaloids are an important group (Schardl members of the family Convolvulaceae, is sys- et al. 2004, 2007). The main ecological roles of temic. Evidence of systemic infection came from ergot alkaloids in nature are probably to