Distribution and Identification of Ectomycorrhizal and Insect Pathogenic Fungi in Icelandic Soil and Their Mediation of Root-Herbivore Interactions in Afforestation
Total Page:16
File Type:pdf, Size:1020Kb
Distribution and identification of ectomycorrhizal and insect pathogenic fungi in Icelandic soil and their mediation of root-herbivore interactions in afforestation Edda Sigurdís Oddsdóttir University of Iceland Rannsóknastöð skógræktar Faculty of Life and Environmental Sciences Icelandic Forest Research Askja, Sturlugötu 7 Mógilsá 101 Reykjavík, Iceland 116 Reykjavík, Iceland Academic Dissertation University of Iceland, Faculty of Life and Environmental Sciences and Icelandic Forest Research Reykjavík, 2010 Research Supervisor Dr. Guðmundur Halldórsson Supervising Teacher Prof. Kesara Anamthawat-Jónsson PhD Advisory Committee Prof. Kesara Anamthawat-Jónsson Prof. Jørgen Eilenberg Dr. Guðmundur Halldórsson Dr. Robin Sen Opponents Prof. Alan Gange Prof. Gísli Már Gíslason Academic dissertation for the degree of Ph.D. in Soil Biology Reykjavík, June 18th 2010 © 2010 Edda Sigurdís Oddsdóttir Printed by Leturprent ISBN 978-9979-9967-3-6 Abstract The objectives of the studies in this thesis were to study the distribution and to identify ectomycorrhizal (ECM) and insect pathogenic fungi (IPF) in native Icelandic birch woodlands and eroded (non-vegetated) soils. Furthermore, to study the mediation of these two beneficial soil fungal groups of plant-herbivore interaction in a model system, which consisted of tree seedlings, Otiorhynchus larvae, IPF and ECM fungi. The study was divided into three steps: 1) mapping the distribution and identifying these target soil beneficial fungi in Icelandic soils originating from birch woodlands, heath land and eroded areas, 2) studying the effects of ECM and IPF fungi on Otiorhynchus sulcatus larvae under controlled situations, and 3) studying the interaction among soil beneficial fungi, Otiorhynchus larvae and tree seedlings in representative afforestation sites. Both ECM and IPF were identified in vegetated ecosystems, whereas no IPF were recorded in eroded ecosystems that also supported significantly lower occurrence of ECM. The low fungal occurrence was reflected in poorer birch seedling performance in eroded soil. Three IPF species were identified: Isaria farinosa, Beauveria bassiana and Metarhizium anisopliae, the latter two species were not previously found in Icelandic soil. Preliminary phylogenetic analysis targeting internal transcribed spacer (ITS) sequences of the major ribosomal gene of mycorrhizal fungi from mycorrhizal birch root tips revealed three main phylogenetic groups: two Basidiomycetes (Hebeloma and Cortinarius) and one Ascomycetes group, of these Hebeloma and Ascomycetes were more common. Inoculation with forest soil, IPF and certain ECM species had negative effects on survival of O. sulcatus under controlled conditions, thus highlighted the importance of careful selection of fungal species used as inoculants in the biological control of Otiorhynchus. The importance of inoculate selection and the need to understand the interaction between the inoculants and native soil biota were further demonstrated under field conditions, where habitat specific, differential root damage response to inoculation was detected. Ágrip Í þessu verkefni eru áhrif tveggja hópa hagnýtra jarðvegssveppa á rótarskemmdir af völdum ranabjöllulirfa rannsökuð. Verkefnið var framkvæmt í þremur skrefum: 1) kortlagning og tegundagreining hagnýtra jarðvegssveppa í mismunandi vistkerfum. Sveppahóparnir sem voru rannsakaðir voru skordýrasníkjusveppir og svepprótarsveppir á trjám, 2) rannsókn á áhrifum svepprótar og skordýrasníkjusveppa á lifun húskepps (Otiorhynchus sulcatus) í gróðurhúsum, og 3) rannsókn á samspili svepprótar, skordýrasníkjusveppa, ranabjöllulirfa (O. arcticus, og O. nodosus) og trjáplantna í mismunandi gróðurvistkerfum. Bæði sníkjusveppir og svepprótarsveppir fundust í grónum vistkerfum (lyngmói og birkiskógur) en engir skordýrasníkjusveppir fundust í uppblásnum vistkerfunum og tíðni svepprótarsveppa var marktækt minni í uppblásnu svæðnum en þeim grónu. Þrjár tegundir sníkjusveppa á skordýrum fundust, Isaria farinosa, Beauveria bassiana og Metarhizium anisopliae, en tvær síðustu tegundirnar höfðu ekki fundist fyrr hér á landi. Fyrstu niðurstöður DNA greiningar á ITS svæði svepprótarsveppa sýndu þrjá mismunandi hópa, tvo hópa basíðusveppa, ættkvíslirnar Hebeloma og Cortinarius og einn hóp asksveppa. Smitun með skógarjarðvegi, skordýrasníkjusveppum og sumum svepprótarsveppum hafði marktæk neikvæð áhrif á lifun húskeppslirfa í gróðurhúsi. Enn fremur hafði smitun með svepprótarsveppum og skordýrasníkjusveppum marktæk áhrif á rótarskemmdir gróðursettra plantna í mörkinni en þau áhrif voru mismunandi eftir þeim vistkerfum sem gróðursett var í. Þessar niðurstöður sýna að smitun með jarðvegsörverum getur dregið úr skemmdum af völdum ranabjöllulirfa á nýgróðursettum plöntum. Jafnframt undirstrika þær mikilvægi þess að velja vel þær sveppategundir sem smitað er með og hve nauðsynlegt er að rannsaka samspil þeirra tegunda sem smitað er með við jarðvegsvistkerfi viðkomandi gróðursetningastaða. To my father Oddur Eggertsson (1949-1994) whose immeasurable interest and love for nature has inspired and encouraged me during this work List of original papers This thesis is based on the following papers: I. Halldorsson, G., Sverrisson, H, Eyjolfsdottir, G.G. and Oddsdottir E.S. (2000). Ectomycorrhizae reduce damage to Russian larch by Otiorhyncus larvae. Scandinavian Journal of Forest Research. 15(3) 354-358. II. Oddsdottir, E.S., Nielsen, C., Sen, R., Harding, S., Eilenberg, J. and Halldorsson, G. Distribution patterns of entomopathogenic fungi in soil and birch symbiotic ectomycorrhizal fungi across native woodland and degraded habitats in Iceland. (submitted to Icelandic Agricultural Sciences) III. Oddsdottir, E.S., Eilenberg, J., Sen, R. and Halldorsson, G. (2010). The effects of insect pathogenic soil fungi and ectomycorrhizal inoculation of birch seedlings on the survival of Otiorhynchus larvae. Agricultural and Forest Entomology (in press) IV. Oddsdottir, E.S., Eilenberg, J., Sen, R., Harding, S. and Halldorsson, G. (2010) Early reduction of Otiorhynchus spp. larval root herbivory on Betula pubescens by beneficial soil fungi. Applied Soil Ecology. doi:10.1016/j.apsoil. 2010.03.009 Papers I, III and IV are reproduced with kind permission from the publishers. In addition, some unpublished data are presented. Author’s contribution Paper I. The study was planned by Gudmundur Halldorsson, Halldor Sverrisson and Gudridur G. Eyjolfsdottir, Edda S. Oddsdottir participated in field work, analyzed the data and participated in writing the paper. Paper II. Edda S. Oddsdottir designed the ectomycorrhizal part together with Robin Sen and Gudmundur Halldorsson. The insect pathogenic component was planned and carried out by Charlotte Nielsen, Susanne Harding and Jørgen Eilenberg. Edda S. Oddsdottir interpreted the results, wrote the paper together with co-authors and is the corresponding author. Paper III. Edda S. Oddsdottir, in collaboration with Gudmundur Halldorsson, designed the experiment and was responsible for the experimental work. She interpreted the results, wrote the paper together with co-authors and is the corresponding author. Paper IV. Edda S. Oddsdottir and Gudmundur Halldorsson designed the experiment and Edda was responsible for the study. She interpreted the results and wrote the paper together with co-authors and is the corresponding author. Contents List of Figures.....................................................................................................................xiii List of Tables....................................................................................................................... xv Abbreviations and definitions.............................................................................................xvi Acknowledgements ...........................................................................................................xvii 1 INTRODUCTION........................................................................................................... 1 1.1 Forestry in Iceland..................................................................................................... 1 1.1.1 Betula spp. ........................................................................................................... 3 1.1.2 Exotic tree species ............................................................................................... 4 1.1.3 Survival of newly planted seedlings.................................................................... 5 1.2 Soil............................................................................................................................. 7 1.2.1 Icelandic soil........................................................................................................ 8 1.3 Soil biota.................................................................................................................. 10 1.3.1 Soil biota in Iceland........................................................................................... 12 1.4 Mycorrhizal fungi.................................................................................................... 15 1.4.1 Roles of mycorrhiza........................................................................................... 17 1.4.2 Mycorrhiza in Iceland........................................................................................ 18 1.5 Insect pathogenic fungi............................................................................................ 22 1.5.1 Roles of insect pathogenic fungi