Comparative proteomic analysis of somatic embryo maturation in Carica papaya L.

Abstract

BackgroundSomatic 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.).ResultsThe 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%).ConclusionsThe 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.

Different environmental conditions at initiation of radiata pine somatic embryogenesis determine the protein profile of somatic embryos

“…This enzyme has been found during late SE in Picea glauca and Carica papaya, suggesting that this protein can be used as a marker of embryo maturation (Lippert et al 2005;Vale et al 2014); However, in our study we obtained somatic embryos in HI and LI which may indicate that in this case this protein do not act as a marker of embryogenicity. Phosphoglycerate kinase (s226) is an enzyme that catalyzes the reversible transfer of a phosphate group from ATP to 3-phosphoglycerate (Fraga et al 2013).…”

“…Indeed, proteome profiling has been successfully applied to the systematic analysis of protein expression in several broad-leaf (Correia et al 2016) and conifer species (Teyssier et al 2011) during the different stages of the development of the somatic embryos. Comparative studies using proteomics to find markers have been carried out by several authors for different aspects of the SE process (Correia et al 2012;Morel et al 2014;Teyssier et al 2011;Vale et al 2014). Proteomic approaches have a great potential to study non-model species, because protein sequences have the advantage of being more conserved, making the high-throughput identification of non-model gene products quite effective by comparison to orthologous proteins (Liska and Shevchenko 2003).…”

Somatic embryogenesis in Carica papaya as affected by auxins and explants, and morphoanatomical-related aspects

“…Despite the low induction frequency of SEs (48.5 SE callus -1 ), the medium containing ABA (0.5 µM) and PEG (60 g L -1 ) very efficiently inhibited precocious germination (4%). Studies have described the ability of PEG to increase the osmolarity of the medium and increase the frequency of somatic embryo induction (Castillón and Kamo 2002, Vooková and Kormuták 2002, Steiner et al 2005, Alkhateeb 2006, Calic-Dragosavac et al 2010, Vale et al 2014. The results achieved with PEG may be related to the non-plasmolyzing osmotic effect of this compound: PEG may be able to induce water stress even if no water actually enters the plant cell (Alkhateeb 2006), and lead to an increased protein synthesis (Heringer et al 2013, Vale et al 2014.…”

“…Studies have described the ability of PEG to increase the osmolarity of the medium and increase the frequency of somatic embryo induction (Castillón and Kamo 2002, Vooková and Kormuták 2002, Steiner et al 2005, Alkhateeb 2006, Calic-Dragosavac et al 2010, Vale et al 2014. The results achieved with PEG may be related to the non-plasmolyzing osmotic effect of this compound: PEG may be able to induce water stress even if no water actually enters the plant cell (Alkhateeb 2006), and lead to an increased protein synthesis (Heringer et al 2013, Vale et al 2014. ABA has been widely used in maturation medium because it can induce the final development of the embryo through the accumulation of LEA proteins (late embryogenesis abundant), related to the maintenance of desiccation tolerance (Dodeman et al 1997, Capelle et al 2010, stimulate the storage of reserve substances (Gutmann et al 1996, Sholi et al 2009) and prevent precocious germination (von Arnold et al 2002).…”

Somatic Embryogenesis in Banana, Musa ssp.

“…Maturation, the final stage of embryo development is distinguished by overall cell expansion and accumulation of reserve substances of the embryo. In general, at this stage, repression of germination and the acquisition of desiccation tolerance, is frequent in the zygotic embryo maturation, and often is lacking in somatic embryo terminal development (Merkle et al 1995;de Moura Vale et al 2014). In several edible bananas genotypes, the basis for the low quality and quantity of the somatic embryos, and the poor regeneration and conversion to vigorous plants is frequently the least studied aspects in banana (Krikorian and Scott 1995).…”