Submitted to: Biomed Central (BMC) Genomics
Publication Type: Peer reviewed journal
Publication Acceptance Date: 11/29/2010
Publication Date: 11/29/2010
Publication URL: hdl.handle.net/10113/49544
Citation: Pechanova, O., Hsu, C., Adams, J.P., Pechan, T., Vandervelde, L., Drnevich, J., Jawdy, S., Adeli, A., Suttle, J.C., Lawrence, A.M., Tschaplinski, T.J., Seguin, A., Yuceer, C. 2010. Apoplast proteome reveals that extracellular matrix contributes to multistress response in poplar. Biomed Central (BMC) Genomics. 11:674. doi:10.1186/1471-2164-11-674. Interpretive Summary: Under natural conditions, plants are simultaneously exposed to both environmental and pathogen-induced stress. Plants respond to these stresses by altering the synthesis and secretion of numerous proteins whose functions are to effectively mitigate these challenges to ensure the survival of the organism. Despite the importance of these stress responses, the actual integration of environmental and pathogen-related defenses is unknown. In this paper, the effects of simultaneous stresses on gene expression and protein content in different tissues of the model species poplar are investigated. Results demonstrate that the stress response differs depending on the tissue examined and that distinct proteins are expressed in leaves, stems, and roots in response to water, pathogen, and oxidative stresses. These are the first results to demonstrate the systematic response of plants to multiple stresses and suggest that each organ has unique mechanisms to counter environmental and pathogen challenges.
Technical Abstract: Riverine ecosystems that are highly sensitive to climate change and human activities are characterized by rapid environmental change to fluctuating water levels and siltation, causing stress on their biological components. We have little understanding of mechanisms by which riverine plant species have developed adaptive strategies to cope with stress in dynamic environments while maintaining growth and development. Here we show that poplar (Populus spp.) has evolved a systems level “stress proteome” in the leaf-stem-root apoplast continuum to counter biotic and abiotic factors. To successfully obtain apoplast proteins from P. deltoides, we developed and used pressure-chamber and water-pressure methods for leaves and stems, respectively. Analyses of 303 proteins and a subset of transcripts along with experiments under controlled conditions demonstrated that poplar depends on constitutive and inducible factors to deal with water, pathogen, and oxidative stress. However, each apoplast possesed a unique set of proteins, indicating that response to stress is partly compartmentalized. Apoplast proteins that are involved in glycolysis, fermentation, and sucrose and starch catabolism appeared to enable poplar to grow normally under water stress. Pathogenesis-related proteins that mediate water and pathogen stress in apoplast were particularly abundant and effective in suppressing growth of the most prevalent poplar pathogen, Melampsora spp. Unexpectedly, we found abundant and diverse peroxidases that appear to be involved in stress-induced cell wall modification in apoplast, particularly during the growing season. Poplar developed a robust antioxidative system to buffer oxidation in stem apoplast. These are important adaptative traits of poplar to respond to multistress and inhabit riverine ecosystems under fluctuating environmental conditions.