Proteins play a central role in the life of any organism. The term proteome is used to describe all proteins expressed in a given cell, tissue or organism. Proteomics is the study of the composition, structure, function and interaction of proteins in a given cell, tissue or organism. Proteomics offers a powerful approach to discover the proteins and pathways that are crucial for plant stress responsiveness and tolerance.

Alison Abbott, a senior European correspondent for "Nature," the international weekly journal of science, once said: "As the full-length sequences of target genomes come into view, biologists know they represent just the start of a long march towards an understanding of how organisms, including humans, develop and function. To many, the next key landmark will be an overview of the characteristics and activity of every protein that an organism can synthesize in its lifetime: 'its proteome'. "

The two key steps in classical proteomics are protein separation and identification using a combined approach of two-dimensional gel electrophoresis (2-DE) and mass spectrometry. Proteins are first separated using 2-DE to develop protein expression profiles.

Mass spectrometry will be used to identify the amino acid sequence and function of each protein that is separated through 2-DE. In recent years, proteomic-based technologies have been successfully applied to the systematic study of the proteomic responses of plants to a wide range of abiotic stresses, including heat, drought, nutrition deficiency, cold, oxidative stress, herbicide, anoxia, salt, ultraviolet-B and metal stress, which have unraveled critical mechanisms of plant stress tolerance (Rossignol et al., 2006).

However, most proteomic studies mainly focused on Arabidopsis (a small annual weed in the mustard family that is the focus of much genetic research) and other crop species. Little has been done to investigate the proteomic response of turgrasses to adverse environments. Our limited knowledge of stress-associated protein metabolism in turfgrass plants remains a major gap in our understanding; therefore, comprehensive profiling of stress-associated proteins is most relevant to further understanding the molecular mechanisms controlling turfgrass stress tolerance. Through global studies of changes in proteins in response to environmental stresses, novel proteins can be identified.

The detailed characterization of stress proteins and their corresponding genes has proven to be of immense practical values. The applications based on results of protein analysis are enormous in production of abiotic stress-tolerant transgenic plants, proving that useful research strategies have emerged based on proteomics information. An example is the identification of late embryogenesis abundant (LEA) proteins and significant improvement of drought and salinity tolerance of various crop species through transferring the LEA gene (Chinnusamy, et al., 2005).

The future avenues for further increasing stress tolerance warrant that stress-related genes must be pyramided. The realization of this goal can only be achieved if major breakthroughs are made in further identification of stress-related proteins and isolation and cloning of the requisite genes.

We have compared the root proteomic response to heat stress between thermal rough bentgrass (thermal Agrostis scabra) and heat-sensitive creeping bentgrass (A. stolonifera), a widely used cool-season turf on golf courses, and have identified some proteins associated with heat tolerance (Xu and Huang, 2008). A. scabra is one of the predominant grass species in thermal areas in Yellowstone National Park. This geothermal grass species can survive and even grow at temperatures up to 45 degrees Celsius to 50 degrees C in soils that are permeated by steam. In contrast, the growth temperature for common cool-season turfgrass species is between 10 degrees C to 18 degrees C for roots and 15 degrees C to 24 degrees C for shoots, and physiological injury and death occur in roots of these species when soil temperatures reach 23 degrees C.