Submitted to: Botanical Society of America Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: April 4, 2007
Publication Date: N/A
Technical Abstract: The majority of desiccation-tolerant plants are found in the less complex clades that constitute the algae, lichens and bryophytes. However, within the larger and more complex groups of vascular land plants there are some 120-130 species that exhibit some degree of vegetative desiccation tolerance. In our earlier work we were able to combine physiological and molecular evidence to fashion a broad overview of the evolution of this important trait. Our recent phylogenetically based comparative genomics studies, using the resources we have developed for representative species of both desiccation-tolerant bryophytes and angiosperms, are beginning to add further insights into this important trait and strengthen the original structure of our evolutionary analysis of desiccation tolerance in the land plants. Our comparisons, primarily based on EST and microarray data, are centered on the desiccation tolerance mechanism expressed by the bryophyte Tortula ruralis and its relationship to mechanisms seen in algae, spikemosses, ferns, and angiosperms (primarily). The data we have assembled point to some major similarities between the various mechanisms and offers an insight into novel aspects in the physiology of desiccation tolerance and the possible identification of those genes that have adaptive relevance for this trait. Interestingly, we have also been able, using the phylogenetic approach of sister group contrasts, to shed light on the evolutionary relationship between vegetative desiccation tolerance and the “water stress” response we see in desiccation-sensitive species such as our major crops. The unraveling of the physiological and molecular aspects of the mechanisms of desiccation tolerance and their evolution in the land plants have important ramifications for our overall understanding of how plants interact with the environment.