AUTHOR=Lim Junsub , Lim Chae Woo , Lee Sung Chul 

TITLE=Functional Analysis of Pepper F-box Protein CaDIF1 and Its Interacting Partner CaDIS1: Modulation of ABA Signaling and Drought Stress Response

JOURNAL=Frontiers in Plant Science

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2019.01365

DOI=10.3389/fpls.2019.01365

ISSN=1664-462X

ABSTRACT=<p>Plant adaptive responses to environmental stress are coordinated by inhibition of plant growth and development. Abscisic acid (ABA) is a major phytohormone that regulates the stress response, and its sensitivity determines stress tolerance levels. In this study, we report the identification and functional role of a novel F-box protein, CaDIF1 (<italic>Capsicum annuum</italic> Drought-Induced F-box Protein 1). The expression of <italic>CaDIF1</italic> in pepper leaves was induced by ABA, drought, H<sub>2</sub>O<sub>2</sub>, and NaCl treatments. In comparison with wild-type pepper plants, <italic>CaDIF1</italic>-silenced pepper plants exhibited a drought-sensitive phenotype, whereas <italic>CaDIF1</italic>-overexpressing (OX) plants exhibited ABA-sensitive and drought-tolerant phenotypes. Using a yeast two-hybrid assay, we identified CaDIS1 (<italic>C. annuum</italic> DIF1-Interacting SKP 1), which interacts with CaDIF1 in the cytoplasm and nucleus. Consistent with <italic>CaDIF1</italic>-silenced pepper plants, <italic>CaDIS1</italic>-silenced pepper plants displayed ABA insensitivity and reduced drought tolerance, and these were characterized by larger stomatal apertures and greater transpirational water loss. Taken together, our results indicate that CaDIF1 and its interacting partner CaDIS1 synergistically regulate the ABA-dependent defence signaling response to drought stress.</p>