This plays a critical role in the impact of sound on living organisms. Plants perceive sound using an unidentified organ. Fruit flies detect vibrations via their antennae, whereas snakes use their jawbones ( Gagliano et al., 2012). Moreover, fruit flies, snakes, frogs, and birds can perceive sound vibrations without an eardrum ( Gagliano et al., 2012). Even insects emit species-specific sounds to help them escape unfavorable conditions or to attract mate ( Djemai et al., 2001). Sound-based communication through the eardrum or specialized mechanosensory systems are commonly found in humans and certain terrestrial mammals ( Grothe et al., 2010). Living organisms produce and perceive sound to help understand the environment around them ( Morales et al., 2010 Aggio et al., 2012). The speed of sound depends on the medium the waves pass through, and is a fundamental property of the material ( McCall, 2010). In air at standard temperature and pressure, the corresponding wavelengths of sound waves range from 17 m to 17 mm. The audible sound that is perceptible by humans has frequencies from about 20 to 20,000 Hz, and above it is ultrasonic. The definition of sound is “a vibration that typically propagates as an audible wave of pressure, through a transmission medium such as a gas, liquid or solid,” and each sound is characterized by its wavelength hertz (Hz), intensity (decibel), speed, and direction ( Shipman et al., 2012). Sound is an omnipresent feature throughout the world ( Theunissen and Elie, 2014). We believe that sound wave treatment is a new trigger to help protect plants against unfavorable conditions and to maintain plant fitness. Here, beyond chemical triggers which can improve plant health by enhancing plant growth and resistance, we provide an overview of the latest findings, limitations, and potential applications of sound wave treatment as a physical trigger to modulate physiological traits and to confer an adaptive advantage in plants. New information is emerging about the responses of plants to sound and the associated downstream signaling pathways. Recent evidence supports the notion that naturally occurring and artificially generated sound waves contribute to plant robustness. 4National Institute of Agricultural Science, Rural Development Administration, Wanju, South Korea.3Personalized Genomic Medicine Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea.2Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, South Korea.1Molecular Phytobacteriology Laboratory, Infectious Disease Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea.Kim 4, Mi-Jeong Jeong 4* and Choong-Min Ryu 1*

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