17 Plant Telomeres

Abstract

The field of telomere biology was pioneered, in large part, through the seminal studies of Barbara McClintock in maize more than 60 years ago. Although many of the key insights in telomere research in the ensuing years have derived from other organisms, there is renewed interest in plant telomere biology as our understanding of the intimate relationship between cellular proliferation and telomere maintenance evolves. This interest is fueled by the striking contrast between the plasticity of plant development and genome architecture, and the much more deterministic nature of mammals. In contrast to mammals, plants produce new organs throughout their lives from meristematic proliferation zones, and many cells in the plant body are totipotent. The plant genome also displays an exceptional plasticity and tolerance to genome stresses, including changes in ploidy, DNA methylation, chromosomal rearrangements, and transposition. Taken together, these features raise fundamental questions about the contribution of telomeres and telomerase in facilitating cell proliferation and genome stability in plants. In the last few years, plant telomere biology has begun to blossom, owing in large part to research with the small flowering plant of the mustard weed family, Arabidopsis thaliana . The completion of the Arabidopsis genome sequencing project and the availability of T-DNA insertion lines that allow for gene knockouts have enabled researchers to make rapid progress in deciphering the functions of several telomere-related genes and in uncovering plant responses to telomere dysfunction. In this review, I focus on recent studies of telomere architecture and function and illustrate how plants are...