From callus to embryo: a proteomic view on the development and maturation of somatic embryos in Cyclamen persicum

Abstract

In this study, the proteome structures following the pathway in somatic embryogenesis of Cyclamen persicum were analysed via high-resolution 2D-SDS-PAGE with two objectives: (1) to identify the significant physiological processes during somatic embryogenesis in Cyclamen and (2) to improve the maturation of somatic embryos. Therefore, the effects of maturation-promoting plant growth regulator abscisic acid (ABA) and high sucrose levels on torpedo-shaped embryos were investigated. In total, 108 proteins of differential abundance were identified using a combination of tandem mass spectrometry and a digital proteome reference map. In callus, enzymes related to energy supply were especially distinct, most likely due to energy demand caused by fast growth and cell division. The switch from callus to globular embryo as well as from globular to torpedo-shaped embryo was associated with controlled proteolysis via the ubiquitin-26S proteasome pathway. Storage compound accumulation was first detected 21 days after transfer to plant growth regulator (PGR)-free medium in early torpedo-shaped embryos. Increase in abundance of auxin-amidohydrolase during embryogenesis suggests a possible increase in auxin release in the late embryo stages of Cyclamen. A development-specific isoelectric point switch of catalases has been reported for the first time for somatic embryogenesis. Several proteins were identified to represent markers for the different developmental stages analysed. High sucrose levels and ABA treatment promoted the accumulation of storage compounds in torpedo-shaped embryos. Additionally, proteins of the primary metabolic pathways were decreased in the proteomes of ABA-treated embryos. Thus, ABA and high sucrose concentration in the culture medium improved maturation and consequently the quality of somatic embryos in C. persicum.

Polyphenols Distribution and Reserve Substances Analysis in Cocoa Somatic Embryogenesis

“…They highlighted seven categories: (1) carbohydrate metabolism; (2) energy metabolism; (3) amino acid metabolism; (4) genetic information processing; (5) cellular processes; (6) stress response; and (7) defense. As described above, embryogenesis is a complex developmental process which is extensively based on carbohydrate metabolism (including sugar conversion), as previously reported in Picea glauca (Iraqi and Tremblay, 2001), Cyclamen persicum (Rode et al, 2012) and in Phoenix dactylifera (Sghaier-Hammami et al, 2009). The explanation for extensive carbohydrate metabolism is the heavy energy demand required for metabolic processes that occur during cell division and elongation (Kroon and Williams, 1999).…”

The Current Status of Proteomic Studies in Somatic Embryogenesis

“…These pairs of distinct cultures have been analyzed using proteomics tools with the goal of identifying proteins markers associated with embryogenic potency (Varhanikova et al 2014;Correia et al 2012;Marsoni et al 2008;Sharifi et al 2012;Almeida et al 2012;Guzmán-García et al 2013). However, these studies have not used sufficiently robust proteomics pipelines and therefore have not covered a comprehensive proportion of the proteome during initiation of the acquisition of the embryogenic potency (Rode et al 2011(Rode et al , 2012. In most of the proteomics studies of somatic embryogenesis, proteins have been analyzed with 2D-SDS-PAGE and mass spectrometry tools (Rode et al 2011(Rode et al , 2012Varhanikova et al 2014;Correia et al 2012;Marsoni et al 2008;Sharifi et al 2012;Almeida et al 2012;Guzmán-García et al 2013;Vale Ede et al 2014).…”

“…However, these studies have not used sufficiently robust proteomics pipelines and therefore have not covered a comprehensive proportion of the proteome during initiation of the acquisition of the embryogenic potency (Rode et al 2011(Rode et al , 2012. In most of the proteomics studies of somatic embryogenesis, proteins have been analyzed with 2D-SDS-PAGE and mass spectrometry tools (Rode et al 2011(Rode et al , 2012Varhanikova et al 2014;Correia et al 2012;Marsoni et al 2008;Sharifi et al 2012;Almeida et al 2012;Guzmán-García et al 2013;Vale Ede et al 2014).…”

“…Several studies have shed light on the important roles of growth regulators, protein receptors, and transcription factors (Martin 2004;Zeynali et al 2010;Cheung and Wu 2011;Wolf and Hofte 2014;Karami et al 2009). Recently, with the surge of "omics" technologies we have been able to generate a more comprehensive panorama of the genome-wide expression profiles during SE (Silva et al 2014;Noah et al 2013;Gomez-Garay et al 2013;Salvo et al 2014;Hoenemann et al 2010;Rode et al 2011Rode et al , 2012. These comprehensive studies allow us to identify specific modifications of genome architecture through epigenetic regulation during SE (Feher 2015;Nic-Can et al 2013;Imin et al 2005).…”

“…Furthermore, proteomic studies of SE in several species have created protein profiles of cultures in different conditions during the induction of embryogenic potential (Varhanikova et al 2014;Correia et al 2012;Marsoni et al 2008;Sharifi et al 2012;Almeida et al 2012;Guzman-Garcia et al 2013). These studies have been followed up with the focused identification of key proteins associated with each stage of the transdifferentiation of somatic embryos (Rode et al 2012;Bian et al 2010;Vale Ede et al 2014). Moreover, the morphological and physiological similarities between zygotic and somatic embryogenesis have suggested similar biochemical status for cells undergoing both of these processes, and protein profiles for zygotic and somatic embryogenesis have been compared in a few plants species (Sghaier-Hammami et al 2009;Winkelmann et al 2006;Noah et al 2013).…”