title: Arabidopsis PYL8 Plays an Important Role for ABA Signaling and Drought Stress Responses.
abstract: Plants are frequently exposed to numerous environmental stresses such as dehydration and high salinity, and have developed elaborate mechanisms to counteract the deleterious effects of stress. The phytohormone abscisic acid (ABA) plays a critical role as an integrator of plant responses to water-limited condition to activate ABA signal transduction pathway. Although perception of ABA has been suggested to be important, the function of each ABA receptor remains elusive in dehydration condition. Here, we show that ABA receptor, pyrabactin resistance-like protein 8 (PYL8), functions in dehydration conditions. Transgenic plants overexpressing PYL8 exhibited hypersensitive phenotype to ABA in seed germination, seedling growth and establishment. We found that hypersensitivity to ABA of transgenic plants results in high degrees of stomatal closure in response to ABA leading to low transpiration rates and ultimately more vulnerable to drought than the wild-type plants. In addition, high expression of ABA maker genes also contributes to altered drought tolerance phenotype. Overall, this work emphasizes the importance of ABA signaling by ABA receptor in stomata during defense response to drought stress.
authors.affiliation: Department of Life Sciences, Chung-Ang University, Seoul 156-756, Korea.
authors.forename: Chae Woo
authors.initials: CW
authors.lastname: Lim
authors.affiliation: Department of Life Sciences, Chung-Ang University, Seoul 156-756, Korea.
authors.forename: Woonhee
authors.initials: W
authors.lastname: Baek
authors.affiliation: Department of Integrative Plant Science, Chung-Ang University, Anseong 456-756, Korea.
authors.forename: Sang-Wook
authors.initials: SW
authors.lastname: Han
authors.affiliation: Department of Life Sciences, Chung-Ang University, Seoul 156-756, Korea.
authors.forename: Sung Chul
authors.initials: SC
authors.lastname: Lee
keywords: ABA receptor; PYL8; RCAR3; abscisic acid; drought stress