|Gasulla, F -|
|Jain, R -|
|Barrano, E -|
|Guera, A -|
|Balbuena, T.S -|
|Thelen, J.J. -|
Submitted to: Plant Cell and Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 26, 2012
Publication Date: July 1, 2013
Repository URL: http://handle.nal.usda.gov/10113/56970
Citation: Gasulla, F., Jain, R., Barrano, E., Guera, A., Balbuena, T., Thelen, J., Oliver, M.J. 2013. The response of Asterochloris erici (Ahmadjian) Skaloud et Peksa to desiccation: a proteomic approach. Plant Cell and Environment. 36:1363-1378. Interpretive Summary: To fully understand what aspects of dehydration tolerance, a critical part of drought tolerance, that are actually critical and adaptive it is necessary to obtain an evolutionary perspective on the cellular events associated with the response to drying. Such insights make it possible to design rational strategies for crop improvement with regards to drought tolerance. In this study we have looked at the details of the cellular response of a terrestrial algae, a plant associated with the most drought tolerant of all orgnisms:lichens. Using the proteomics approach, a global look at the protein level response of the cells, we have determined that proteins involved in dehydration tolerance have structural activities that limit damage. We have also shown that the algae are consitutively tolerant and do not need a signal to induce their ability to survive drying. These results lead to several new hypotheses that will lead us to explore the possibility of investigating the role of cell structural components in drought tolerance phenotypes in crops.
Technical Abstract: The study of desiccation tolerance of lichens, and of their photobionts in particular, has frequently focused on the antioxidant system that protects the cell against photo-oxidative stress during dehydration/rehydration cycles. Thus, in this work we carried out proteomic and transcript analyses of the changes associated with desiccation in the isolated photobiont Asterochloris erici. Algae were dried either slowly (5 - 6 h) or rapidly (< 60 min), and were rehydrated after 24 h in the desiccated state. To identify those proteins that accumulated during the drying or the rehydration processes, we employed 2-D Difference Gel Electrophoresis (DIGE) coupled with individual protein identification using trypsin digestion and LC-MS/MS. Proteomic analyses revealed that desiccation caused an up-regulation of only 11-13 proteins - either after rapid and slow drying - involved in glycolisis, cellular protection, cytoskeleton, cell cycle and targeting and degradation. Transcripts of five Hsp90 and two ß-tubulin genes were accumulated mainly at the end of the dehydration process. These results suggest that desiccation tolerance of A. erici is achieved by constitutive mechanisms. However, TEM images showed that ultrastructural cell injuries were more intense after a rapid dehydration, which might result from physical or mechanical stresses, rather than metabolic damage.