title: Rapid degradation of Pseudomonas fluorescens 1-aminocyclopropane-1-carboxylic acid deaminase proteins expressed in transgenic Arabidopsis.
abstract: 1-Aminocyclopropane-1-carboxylate (ACC) deaminase is commonly produced by plant growth-promoting rhizobacteria (PGPR) and has been suggested to facilitate the growth and stress tolerance of hosts via a reduction in levels of ethylene. However, the regulatory mechanism of ACC deaminase (AcdS) protein within host plant cells is largely unknown. Here, we demonstrated beneficial effects and post-translational modification of PGPR-originated AcdS proteins in plants. Compared with the wild-type, transgenic Arabidopsis expressing the Pseudomonas fluorescens acdS (PfacdS) gene displayed increased root elongation and reduced sensitivity to 10 μM exogenous ACC, an ethylene precursor. Arabidopsis expressing PfacdS also showed increased tolerance to high salinity (150 mM NaCl). PfAcdS proteins accumulated in transgenic Arabidopsis were rapidly degraded, which was potentially mediated by the 26S proteasome pathway. The degradation of PfAcdS was alleviated in the presence of exogenous ACC. In conclusion, our data suggest that the plant growth-promoting effects of bacterial AcdS proteins are potentially modulated via protein turnover inside the host plant cells. Such post-translational modification plays a physiological role in the mutualistic interactions between microorganisms and plants in the rhizospheric and/or endospheric niche.
authors.affiliation: Division of Biotechnology, College of Environmental & Bioresource Sciences, Chonbuk National University, Iksan, Korea; Advanced Institute of Environment and Bioscience, Chonbuk National University, Iksan, Korea.
authors.forename: Kangmin
authors.initials: K
authors.lastname: Kim
authors.forename: Sung-Hee
authors.initials: SH
authors.lastname: Park
authors.forename: Jong-Chan
authors.initials: JC
authors.lastname: Chae
authors.forename: Byoung Yul
authors.initials: BY
authors.lastname: Soh
authors.forename: Kui-Jae
authors.initials: KJ
authors.lastname: Lee
mesh_terms: D000598:Amino Acids, Cyclic / Q000378:metabolism; D017360:Arabidopsis / Q000235:genetics / Q000382:microbiology / Q000502:physiology*; D019755:Carbon-Carbon Lyases / Q000235:genetics / Q000378:metabolism*; D005030:Ethylenes / Q000378:metabolism; D018517:Plant Roots / Q000235:genetics / Q000382:microbiology; D030821:Plants, Genetically Modified / Q000382:microbiology; D011499:Protein Processing, Post-Translational; D055550:Protein Stability; D011551:Pseudomonas fluorescens / Q000201:enzymology* / Q000235:genetics; D013559:Symbiosis
chemical_list: D000598:Amino Acids, Cyclic; D005030:Ethylenes; C023863:1-aminocyclopropane-1-carboxylic acid; C036216:ethylene; C033634:1-aminocyclopropane-1-carboxylate deaminase; D019755:Carbon-Carbon Lyases
keywords: 1-aminocyclopropane-1-carboxylate; ethylene; protein degradation; salt stress