title: Comparative proteomic analysis of somatic embryo maturation in Carica papaya L.
abstract: BACKGROUND
  Somatic embryogenesis is a complex process regulated by numerous factors. The identification of proteins that are differentially expressed during plant development could result in the development of molecular markers of plant metabolism and provide information contributing to the monitoring and understanding of different biological responses. In addition, the identification of molecular markers could lead to the optimization of protocols allowing the use of biotechnology for papaya propagation and reproduction. This work aimed to investigate the effects of polyethylene glycol (PEG) on somatic embryo development and the protein expression profile during somatic embryo maturation in papaya (Carica papaya L.).
  
  
  RESULTS
  The maturation treatment supplemented with 6% PEG (PEG6) resulted in the greatest number of somatic embryos and induced differential protein expression compared with cultures grown under the control treatment. Among 135 spots selected for MS/MS analysis, 76 spots were successfully identified, 38 of which were common to both treatments, while 14 spots were unique to the control treatment, and 24 spots were unique to the PEG6 treatment. The identified proteins were assigned to seven categories or were unclassified. The most representative class of proteins observed in the control treatment was associated with the stress response (25.8%), while those under PEG6 treatment were carbohydrate and energy metabolism (18.4%) and the stress response (18.4%).
  
  
  CONCLUSIONS
  The differential expression of three proteins (enolase, esterase and ADH3) induced by PEG6 treatment could play an important role in maturation, and these proteins could be characterized as candidate biomarkers of somatic embryogenesis in papaya.
authors: Laboratório de Biotecnologia, Centro de Biociências e Biotecnologia (CBB), Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Av. Alberto Lamego 2000, Campos dos Goytacazes, RJ 28013-602, Brazil.
authors: Ellen de Moura
authors: Ede M
authors: Vale
authors: Laboratório de Biotecnologia, Centro de Biociências e Biotecnologia (CBB), Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Av. Alberto Lamego 2000, Campos dos Goytacazes, RJ 28013-602, Brazil.
authors: Angelo Schuabb
authors: AS
authors: Heringer
authors: Laboratório de Biotecnologia, Centro de Biociências e Biotecnologia (CBB), Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Av. Alberto Lamego 2000, Campos dos Goytacazes, RJ 28013-602, Brazil.
authors: Tatiana
authors: T
authors: Barroso
authors: Laboratório de Toxinologia da Fundação Oswaldo Cruz, Instituto Oswaldo Cruz. Instituto Oswaldo Cruz /IOC /FIOCRUZ, Av. Brasil, 4365. Manguinhos, CEP: 21040-360 Rio de Janeiro, RJ, Brazil.
authors: André Teixeira da Silva
authors: AT
authors: Ferreira
authors: Laboratório de Toxinologia da Fundação Oswaldo Cruz, Instituto Oswaldo Cruz. Instituto Oswaldo Cruz /IOC /FIOCRUZ, Av. Brasil, 4365. Manguinhos, CEP: 21040-360 Rio de Janeiro, RJ, Brazil.
authors: Monique Nunes
authors: MN
authors: da Costa
authors: Laboratório de Toxinologia da Fundação Oswaldo Cruz, Instituto Oswaldo Cruz. Instituto Oswaldo Cruz /IOC /FIOCRUZ, Av. Brasil, 4365. Manguinhos, CEP: 21040-360 Rio de Janeiro, RJ, Brazil.
authors: Jonas Enrique Aguilar
authors: JE
authors: Perales
authors: Laboratório de Biologia Celular e Tecidual, CBB-UENF, Av. Alberto Lamego 2000, Campos dos Goytacazes, RJ 28013-602, Brazil.
authors: Claudete
authors: C
authors: Santa-Catarina
authors: Laboratório de Biotecnologia, Centro de Biociências e Biotecnologia (CBB), Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Av. Alberto Lamego 2000, Campos dos Goytacazes, RJ 28013-602, Brazil.
authors: Vanildo
authors: V
authors: Silveira
keywords: Mass spectrometry; Papaya; Protein profile; Somatic embryogenesis; Two-dimensional electrophoresis