Raikoke is a small volcanic island in the Kuril Archipelago for which there has been no previously published botanical research or plant list. Although Tatewaki and Tokunaga collected on the island ...in 1928, no subsequent botanical investigations were made until the field work performed under the auspices of the International Kuril Island Project (IKIP) in 1996 and 2000. A first plant checklist, including the specimens collected in 1928, is presented here and includes 27 families, 53 genera, and 68 species for the island. Shrubs of Salix subreniformis and S. aquilonia are common on the volcanic ash slope, but Alnus maximowiczii and Sorbus sambucifolia are very rare. Pinus pumila was not found, which is surprising since it is common on other islands in the area. Shrub belts composed of Pinus or Alnus have not formed on the island, indicating that the island remains at an early stage of plant succession after the 1924 volcanic eruption. Establishment of Salix may be easier than that for Alnus or Pinus in the central Kuril Islands because of the more effective long distance seed dispersal in Salix, although the vegetative reproduction of survivors after the volcanic eruption cannot be ruled out. True ferns (Polypodiophyta) appear to be rare on Raikoke.
A lichen thallus is an emergent structure formed through the long-lived symbiotic growth of a filamentous fungus and uni-cellular green algae. How the symbionts find and recognize each other, resist ...potential attack, and proceed to form this unique body remains enigmatic. Based on other well-studied eukaryotic systems, the development of a lichen thallus must rely upon the successful identification and collaboration of these two very different organisms. Identifying the molecular basis of microbe recognition and interactions remains one of the greatest challenges in studying symbiotic systems. In the development of stratified lichen thalli containing trebouxioid algae, the mycobiont undergoes a change in hyphal morphology when making physical contact with its photobiont. This change is characterized by a switch from apical growth to increased lateral branching, and has been proposed to be a result of thigmotropism (response to shape). This morphological change can be seen when the mycobiont Cladonia grayi contacts its symbiotic partner, the trebouxioid photobiont Asterochloris sp. Therefore, observations were made using environmental scanning electron microscopy, glass beads, alternative phototrophs, and the development of the lichen symbiosis between C. grayi and Asterochloris sp. The results of these observations confirmed that the change in growth pattern of C. grayi in lichen symbiosis is not a result of thigmotropism or fungal contact with phototrophs, but instead is diagnostic of lichen symbiosis. This phenotypically defined stage was next used to begin studying the genetic and molecular mechanisms underlying lichen-symbiosis development. Using suppression subtractive hybridization to determine differential gene expression, fungal and algal libraries were made of putatively upregulated genes in the pre-contact and initially post-contact stages of lichen symbiosis. The symbiotic expression levels of select genes were then verified using quantitative PCR. Fungal protein products of genes upregulated in lichen symbiosis show significant matches to proteins putatively involved in fungal self and non-self recognition, lipid metabolism, negative regulation of glucose repressible genes, an oxidoreductase, a dioxygenase, and a conserved hypothetical protein. Algal genes that are upregulated in lichen symbiosis include a chitinase-like protein, an amino acid metabolism protein, a dynamin related protein, and a protein arginine methyltransferase. Furthermore, early stages in lichen development are marked not by a drastic change in transcriptional products, but instead by an overall change in genes that are already expressed. Finally, one of the candidate fungal genes upregulated in the initial post-contact stage of lichen development, Lip3, was cloned from Cladonia grayi cDNA, and heterologously expressed in yeast. The protein product of this gene was shown to be a functional secreted extracellular lipase.
Lichen-forming fungi employ a successful mode of nutrition as symbiotic partners with green algae and/or cyanobacteria (the photobiont). Nearly one fifth of all known fungi are obligate lichen ...formers, yet we know little of how they find compatible partners and establish long-lived symbiotic relationships. The combined growth of these symbionts forms a body (thallus) with emergent properties unlike either of the symbionts individually grown. Based on other well-studied eukaryotic systems, the development of a lichen thallus must rely upon the successful identification and collaboration of these two very different organisms. Identifying the molecular basis of microbe recognition and interactions remains one of the greatest challenges in studying symbiotic systems. In this thesis, I determine the stage in which to begin looking for lichen symbiosis specific genes, and then examine mycobiont and photobiont genes that, when compared to the aposymbiotic state, are upregulated in the symbiotic state. Using the symbiosis between the mycobiont Cladonia grayi and the photobiont Asterochloris sp., as well as scanning electron microscopy observations of the earliest stages of contact between C. grayi and Asterochloris sp., I determined that the mycobiont undergoes a specific change in phenotypic growth in response to Asterochloris sp. This change is particular to the lichen symbiosis, and is not observed with algal shaped inanimate objects or algae other than Asterochloris. I then used this phenotypically defined stage that is exclusive to lichen symbiosis to begin studying the the genetic and molecular mechanisms underlying the development of a stratified lichen thallus. Using suppression subtractive hybridization to determine differential gene expression, fungal and algal libraries were made of upregulated genes in the first 2 stages of lichen symbiosis. The symbiotic expression levels of select genes were then verified using quantitative PCR. Lastly, a candidate gene for involvement in lichen symbiosis was transformed into Saccharomyces cerevisiae to test for protein function.Further results of this study show that the fungal protein products of genes upregulated in lichen symbiosis show significant matches to proteins putatively involved in fungal self and non-self recognition, lipid metabolism, negative regulation of glucose repressible genes, an oxidoreductase, a dioxygenase, and a conserved hypothetical protein. Algal genes that are upregulated in lichen symbiosis include a chitinase-like protein, an amino acid metabolism protein, a dynein related protein, and a protein arginine methyltransferase. Furthermore, genes that are expressed in the early stages of lichen symbiosis are common varying metabolic pathways. Furthermore stages 1 and 2 of development are marked not by a drastic change in transcriptional products, but instead by an overall change in genes that are already expressed. Finally, the Cladonia~grayi Lip3was cloned in its entirety from genomic DNA and cDNA, was predicted to be secreted using signal peptide prediction software, and shown to be a functioning secreted extracellular lipase in yeast.I conclude that many genes are involved in the interactions of symbionts and the development of a stratified lichen thallus, and that many more genes remain to be discovered. Furthermore, the possibility that genes exist in either symbiont that are specific to lichen symbiosis remains, and that their discovery awaits the creation of better genomic tools for \textit{Cladonia~grayi} and Asterochloris.
Dissertation
Ramalina of the Kuril Islands Joneson, Suzanne; Kashiwadani, Hiroyuki; Tschabanenko, Svetlana ...
The Bryologist,
03/2004, Letnik:
107, Številka:
1
Journal Article
Recenzirano
Ten species of Ramalina Ach. are reported from the Kuril Islands, Far Eastern Russia. This is the first complete account of the Ramalina distribution from Japan to the Russian peninsula of Kamchatka. ...The Ramalina flora of the Kuril Islands represents a unique combination of species found in outlying areas, and the distribution of individual species throughout the archipelago corresponds with changes in island size, proximity to larger bodies of land, and climate.
Acroscyphus sphaerophoroides Lév. is reported new to Washington State (U.S.A.) Previously this rare and monotypic fruticose lichen has been reported from North America only in Veracruz, Mexico and ...British Columbia, Canada. We are unable to verify the collection from Mexico at this time, however it's locality near Perote in the highlands of southern Mexico fits with a southern extension of boreal forests down the cordilleras of western North America, and an overall disjunct worldwide distribution from high exposed regions of China, Japan, Peru, Patagonia, and South Africa. Listing of this species as critically imperiled is strongly recommended for Washington State.
