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2001 Annual Science Report

University of Colorado, Boulder Reporting  |  JUL 2000 – JUN 2001

Symbiosis and the Origin of Multicellularity in Photosynthetic Organisms

4 Institutions
3 Teams
0 Publications
0 Field Sites
Field Sites

Project Progress

Symbiosis and the origin of multicellularity in photosynthetic organisms (dm)

Symbioses, the mutually beneficial relationships between two organisms, have evolved numerous times over the course of the evolutionary history of life on Earth. Different forms of symbiosis have resulted in some of the most profound evolutionary radiations; e.g., the origin of the mitochondrion from a symbiosis of a proteobacterium with early eukaryotes, the origin of the chloroplast from a symbiosis of a cyanobacterium with an originally heterotrophic eukaryote resulting in the evolution of all photosynthetic lines of eukaryotes, and the establishment of multicellular photosynthetic organisms (plants) in terrestrial environments from a symbiosis of a fungus and a green alga.

We have begun to study, for the first time, the actual fungal symbiotic partners that may have been critical to the colonization of terrestrial environments on earth by photosynthetic organisms. Using DNA extraction and amplification techniques, we have begun to identify the fungal lineages that currently play a central role in the widespread symbiosis between plants and fungi (mycorrhizal association). We have chosen to work with phylogenetically basal land plant lineages so that we can reconstruct the evolutionary history of this key symbiosis.

During the last year, a synthesis of the developmental biology of cells that conduct water within the body of terrestrial plants was completed and published in the Philosophical Transactions of the Royal Society. The goal of this work was provide developmental insights for the paleontological community in their analysis of the earliest phases of the origin of terrestrial photosynthetic life and the microfossil record that was left behind.

    William Friedman

    Jennifer Winther
    Doctoral Student

    Objective 4.0
    Expand and interpret the genomic database of a select group of key microorganisms in order to reveal the history and dynamics of evolution.

    Objective 6.0
    Define how ecophysiological processes structure microbial communities, influence their adaptation and evolution, and affect their detection on other planets.

    Objective 10.0
    Understand the natural processes by which life can migrate from one world to another. Are we alone in the Universe?