Endorhizal FungiCurrent Projects Completed Projects
Fungal root symbionts are essential for the survival and growth of terrestrial plants. Arbuscular mycorrhizae are abundant even in plant roots growing on High Arctic tundra. Habitat-specific septate endophyte fungi confer tolerance for plants growing in otherwise extreme environments. Although the metabolic mechanisms are not yet understood, habitat-adaptive endophytes appear to increase water use efficiency of the plants with which they are associated.
Basinger's Axel Heiberg site is notable for having a diverse Eocene (40 million year old) temperate forest comprised of species whose nearest living relatives are now in southern China. These fossils are exquisitely well-preserved, leading to the possibility that ancient mycorrhizal and other plant:fungal interactions will also be available for study. The "Fossil Forest" at 80°N on Axel Heiberg Island has plants with abundant arbuscular mycorrhizae (AM) unlike any other high latitude site currently documented. This is a unique place to assess Arctic AM function.
Agriculture on saline soils is associated with reduced crop yield. Soil salinity increases with long-term use of irrigation, and threatens coastal regions with inundation as sea levels rise. Many Saskatchewan soils are naturally salty. The picture below shows the shore of Chaplain Lake in southern Saskatchewan. The white material is salt, probably sodium sulphate, which is commercially extracted from the lake. We are testing fungal endophytes in the sparse vegetation from this and other similar sites for their ability to confer tolerance to salinity.
My research is characterizing fungal endophyte strains that confer salt tolerance to plants.
Saskatchewan has naturally salty soils, and human activities are also associated with soil salinization. Both cause reduced crop yields.
Endophyte technology has the potential to improve agricultural yield without using genetically modified organisms.
Dominic Olver Tim Repas Huimin Zhang Dr. Zakia Boubakir Savanna Menke Liz Cronin Laurie Johnson Xiaohui Bao Yang (Lilia) Li Catherine Peters Xanthe Walker Fakhra Shahid Nathan Allen
I worked with Kumkum Azad to characterize salt tolerance endophytes. My project will compare salinity of the environment compared to plant fluids.
My TSTH20-1 project has progressed to mesocosm growth studies, since preliminary results strongly suggested this fungus was able to metabolize residual bitumen in the tailing sands. We expect this will provide a practical strategy for establishing early successional plant communities on tailing sands. We hope to take this to field trials in 2013.I am now funded by an NSERC Industrial Post-Graduate Scholarship, in partnership with Novozymes BioAg. I am characterizing a novel strain on phosphate-solubilizing fungus, previously isolated by the Kaminskyj Endophyte group.
I worked with Kumkum Azad on
characterizing fungal endophytes
that contributed to salt tolerance.
I lead the Saline Endophyte group, characterizing fungal strains that were isolated from plants that naturally grew in Mosaic Co tailings management areas (TMAs), which have high levels of sodium chloride (table salt). After earning my PhD from Braunschweig University in Germany, I had a 3-year post-doctoral fellowship at the Plant Biotechnology Institute in Saskatoon before joining the Kaminskyj lab.
This image is of a tomato seedling that was forgotten (and not watered) for nearly four weeks in a plant growth room. The label “422.08” indicates it was colonized with one of our endophyte strains. Seven weeks later this tomato superhero has three young fruit!
Savanna Menke: Saline endophytes
I am a Centennial Collegiate student entering grade 12. My first project was characterizing nutrient requirements of endophyte fungi with Tim Repas. Now I work on the saline endophyte project, helping with analysis of several dozen fungal isolates and their effect on plant salinity tolerance.
I am a U Vic Co-op student, spending my final undergrad term studying fungal endophytes and salt tolerance. I am working with Zakia to rescreen and confirm results from 2012.The image on the left shows young radish seedlings, chosen for their extremely delicate roots. After 6 days in our new DE-granule growth medium, we can remove the plants without damage to the roots (image on the right).
Terrestrial plants use symbioses with endophyte and mycorrhizal fungi to enhance survival. One group of endophyte fungi helps plants to survive in harsh environments, for example, being specialized for cold or dry or low-nutrient conditions. My project studied endophytes from the Canadian High Arctic and from local deserts like the Great Sand Hills of southwestern Saskatchewan. Wheat that had been colonized by specific endophyte germinated faster and grew significantly larger within the first week after seeding. These isolates may help agriculture without added chemicals.
Arbuscular mycorrhizae (AM) are associated with ~80% of terrestrial plant species, where they contribute to plant survival and competitiveness by supplying minerals in exchange for sugars produced by photosynthesis. Our lab has shown that AM and other fungal root associates are common even in extreme environments. I am studying root fungi associated with plants like dandelions that are able to grow on tar sands following extraction, a process that intuitively seems likely to have removed all possible soil microbes. Plants that can colonize this extreme environment may be useful for re-establishing soil micro-ecology in a relatively natural and cost-effective manner.
The Athabasca Tar Sands are a vast hydrocarbon reserve in western Canada that are a natural model system to understanding how mycorrhizal fungi respond to petrochemicals. The hydrocarbons are extracted using solvents and hot water, after which the sand is remediated to permit revegetation. I am studying mycorrhizal fungi associated with Taraxacum officinale (common dandelion) collected from unextracted, extracted, and remediated sites. This photo shows that, following extraction of bituminous tar, clean mineral sand has become colonized by dandelions and sowthistle. Surprisingly, although the extraction process was expected to severely deplete the soil microflora, preliminary studies showed that the dandelion roots have abundant AM typical of unextracted sites.
Taraxacum officinale (dandelion) lateral roots form arbuscular mycorrhizae (AM) as well as other root-fungal endophyte associations. I am examining roots containing multiple types of fungi using light, confocal epifluorescence and electron microscopy (EM).
Image to the right: confocal fluorescence microscopy of dandelion roots stained with lactofuchsin shows an aseptate AM hypha (arrow) that has produced arbuscules (A) near the vascular cylinder (V) that forms the core of the root. In addition, septate endophytic hyphae (arrowheads indicate septa) can be found throughout the root cortex. AM and septate fungi often occur close together. In future these species will be identified using molecular methods. This is the first ultrastructural study of dandelion lateral roots. These have closely packed cells in the peripheral cortex, and gaps between cells near the vascular cylinder, consistent with variations in AM morphology. EM will be used to characterize interactions between plant and fungal cells.
Truelove Lowland, on Devon Island in the Canadian High Arctic archipelago, has been studied since the 1970s as a model for tundra ecology. However, despite intensive study in the late 1980s (Bledsoe et al. 1990 Can J Bot 68: 1848-1856) no plants were found to host endorhizal fungal associations. Recent work in our lab (Ormbsy et al. 2007 Can J Bot, in press) showed that endorhizal fungi were more common in 2004 and 2006 than in previous years, at least for Asteraceae collected on Axel Heiberg Island. Using plant and soil samples collected at Truelove in 2005 from about 20 species, and sensitive confocal fluorescent microscopy methods for visualizing endorhizal fungi, I will be revisiting whether endorhizal fungi are indeed absent from Truelove.
Ranunculus (buttercups) are small herbaceous plants found from the Prairies to the High Arctic, where they are common in moist to marshy sites. Mycorrhizal fungi have seldom been reported from plants growing on wet soils, however our lab showed (Allen et al. 2006 Can J Bot 84: 1094-1100) these fungi are abundant in High Arctic Ranunculus. My project is to characterize endorhizal fungi in Ranunculus from diverse Arctic and Prairie sites.
The image shows Ranunculus nivalis from Axel Heiberg Island, 80ºN, growing by a stream with a temperature of 2.9ºC.
Equisetum (horsetails) is the sole remaining genus from a group of primitive plants that were abundant in the Carboniferous period. Today Equisetum is a dominant understory plant in boreal and mixed forests, although the inset shows it can also colonize disturbed sites. I am continuing work to characterize fungi associated with Equisetum roots, in order to better understand their role(s) in forest soil microbial ecology.
Arctic plants endure harsh conditions but relatively little is known about their mycorrhizae, due to difficulty of access to remote regions. My current project is to compare arbuscular mycorrhizae (AM) of temperate (Taraxacum officinale) and arctic (T. arcticum and T. hyparcticum) dandelion, imaged with confocal laser scanning microscopy (CLSM).
This CLSM fluorescence image shows a Taraxacum officinale arbuscular mycorrhiza stained with lactofuchsin. Click the above to play the movie (22 MB). (Larger, crisper still)
This arctic dandelion was collected on Axel Heiberg Island in the Canadian Arctic archipelago.
This arctic dandelion was collected on Axel Heiberg Island in the Canadian Arctic archipelago.