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United States Department of Agriculture

Agricultural Research Service

Research Project: ECOPHYSIOLOGICAL, BIOCHEMICAL, AND MOLECULAR MECHANISMS OF DESICCATION TOLERANCE IN THE FERNS

Location: Plant Genetics Research

Project Number: 3622-21000-034-04
Project Type: Reimbursable

Start Date: May 04, 2010
End Date: Sep 30, 2012

Objective:
Elucidate the mechanism of dehydration tolerance in a model plant (fern) that differs in the level of tolerance between different life stages. The objective is to profile genes that respond to dehydration and rehydration and the degree of their expresssion, and to employ molecular phylogenomics to understand better how molecular mechanisms are related across green plants.

Approach:
This work will examine species from three different habitats in Costa Rica: tropical dry forest, tropical lowland rain forest, and tropical high elevation paramo. Each site will be assessed and monitored for microclimate characteristics. Initial ecophysiological surveys of dessication tolerance (DT) will be made on field collected samples in Costa Rica. Others will be brought back to the US for detailed DT studies. At least for species from each habitat will be grown under controlled conditions. The DT capabilities for gametophytes and sporophytes for each species will be determined experimentally using controlled drying regimes coupled with survival assays and cell leakage measurements. The effect of dehyration on various physiological parameters (photosynthesis, respiration, water relations) will be assessed. Mechanisms of tolerance will be assessed by following the behavior of key cellular components during a wet-drywet cycle: including dehydrins (stress proteins), carbohydrates and key antioxidants. Dehydrins are of particular interest, as we will look at the gene structure, expression and protein accumulation patterns for each species. These measurements will form the basis of our molecular phylogenomics investigations.

Last Modified: 9/10/2014
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