title: PCA22 acts as a suppressor of atrzf1 to mediate proline accumulation in response to abiotic stress in Arabidopsis.
abstract: Proline metabolism is important for environmental responses, plant growth, and development. However, its precise roles in plant abiotic stress tolerance are not well understood. Mutants are valuable for the identification of new genes and for elucidating their roles in physiological mechanisms. We applied a suppressor mutation approach to identify novel genes involved in the regulation of proline metabolism in Arabidopsis. Using the atrzf1 (Arabidopsis thaliana ring zinc finger 1) mutant as a parental line for activation tagging mutagenesis, we selected several mutants with suppressed induction of proline accumulation under dehydration conditions. One of the selected mutants [proline content alterative 22 (pca22)] appeared to have reduced proline contents compared with the atrzf1 mutant under drought stress. Generally, pca22 mutant plants displayed suppressed atrzf1 insensitivity to dehydration and abscisic acid during early seedling growth. Additionally, the pca22 mutant exhibited shorter pollen tube length than wild-type (WT) and atrzf1 plants. Furthermore, PCA22-overexpressing plants were more sensitive to dehydration stress than the WT and RNAi lines. Green fluorescent protein-tagged PCA22 was localized to the cytoplasm of transgenic Arabidopsis cells. Collectively, these results suggest that pca22 acts as dominant suppressor mutant of atrzf1 in the abiotic stress response.
authors.affiliation: Department of Plant Biotechnology, Chonnam National University, Gwangju 61186, Republic of Korea.
authors.forename: Ah-Reum
authors.initials: AR
authors.lastname: Kim
authors.affiliation: Department of Plant Biotechnology, Chonnam National University, Gwangju 61186, Republic of Korea.
authors.forename: Ji-Hee
authors.initials: JH
authors.lastname: Min
authors.affiliation: Department of Rural and Biosystems Engineering, Agricultural Robotics and Automation Research Center, Chonnam National University, Gwangju 61186, Republic of Korea.
authors.forename: Kyeong-Hwan
authors.initials: KH
authors.lastname: Lee
authors.affiliation: Department of Plant Biotechnology, Chonnam National University, Gwangju 61186, Republic of Korea.
authors.forename: Cheol Soo
authors.initials: CS
authors.lastname: Kim
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics* / Q000378:metabolism; D010802:Phylogeny; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D011392:Proline / Q000378:metabolism*; D016415:Sequence Alignment; D013312:Stress, Physiological
chemical_list: D029681:Arabidopsis Proteins; D047908:Intracellular Signaling Peptides and Proteins; C000627710:PCA22 protein, Arabidopsis; C000624899:RZF1 protein, Arabidopsis; D011392:Proline
keywords: Abiotic stress response; AtRZF1; pca mutant; pollen tube length; proline metabolism; suppressor.