title: Constitutive expression of CaRma1H1, a hot pepper ER-localized RING E3 ubiquitin ligase, increases tolerance to drought and salt stresses in transgenic tomato plants.
abstract: CaRma1H1, an endoplasmic reticulum (ER)-localized hot pepper really interesting new genes (RING) E3 Ub ligase, was previously reported to be a positive regulator of drought stress responses. To address the possibility that CaRma1H1 can be used to improve tolerance to abiotic stress in crop plants, CaRma1H1 was constitutively expressed in transgenic tomato (Solanum lycopersicum) plants. CaRma1H1-overexpressing tomato plants (35S:CaRma1H1) exhibited greatly enhanced tolerance to high-salinity treatments compared with wild-type plants. Leaf chlorophyll and proline contents in CaRma1H1 overexpressors were 4.3- to 8.5-fold and 1.2- to 1.5-fold higher, respectively, than in wild-type plants after 300 mM NaCl treatment. Transgenic cotyledons developed and their roots elongated in the presence of NaCl up to 200 mM. In addition, 35S:CaRma1H1 lines were markedly more tolerant to severe drought stress than were wild-type plants. Detached leaves of CaRma1H1 overexpressors preserved water more efficiently than did wild-type leaves during a rapid dehydration process. The ER chaperone genes LePDIL1, LeBIP1, and LeCNX1 were markedly up-regulated in 35S:CaRma1H1 tomatoes compared with wild-type plants. Therefore, overexpression of CaRma1H1 may enhance tomato plant ER responses to drought stress by effectively removing nonfunctional ubiquitinated proteins. Collectively, constitutive expression of CaRma1H1 in tomatoes conferrred strongly enhanced tolerance to salt- and water-stress. This raises the possibility that CaRma1H1 may be useful for developing abiotic stress-tolerant tomato plants.
  
  
  CONCLUSIONS
  CaRma1H1 increases drought tolerance in transgenic tomato plants.
authors.affiliation: Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, 120-749, Korea.
authors.forename: Young Sam
authors.initials: YS
authors.lastname: Seo
authors.forename: Jun Young
authors.initials: JY
authors.lastname: Choi
authors.forename: Soo Jin
authors.initials: SJ
authors.lastname: Kim
authors.forename: Eun Yu
authors.initials: EY
authors.lastname: Kim
authors.forename: Jeong Sheop
authors.initials: JS
authors.lastname: Shin
authors.forename: Woo Taek
authors.initials: WT
authors.lastname: Kim
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects*; D002212:Capsicum / Q000187:drug effects / Q000201:enzymology*; D055864:Droughts; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism*; D018551:Solanum lycopersicum / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D010940:Plant Proteins / Q000378:metabolism; D030821:Plants, Genetically Modified; D021381:Protein Transport / Q000187:drug effects; D054712:Salinity; D012965:Sodium Chloride / Q000494:pharmacology*; D013312:Stress, Physiological / Q000187:drug effects; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism*
chemical_list: D010940:Plant Proteins; D012965:Sodium Chloride; D044767:Ubiquitin-Protein Ligases