Quantitative proteomic analysis of Araucaria angustifolia (Bertol.) Kuntze cell lines with contrasting embryogenic potential

Abstract

GeLC–MS/MS based label free proteomic profiling was used in the large scale identification and quantification of proteins from Brazilian pine (Araucaria angustifolia) embryogenic cell (EC) lines that showed different propensities to form somatic embryos. Using a predicted protein sequence database that was derived from A. angustifolia RNA-Seq data, 2398 non-redundant proteins were identified. The log2 of the spectral count values of 858 proteins of these proteins showed a normal distribution, and were used for statistical analysis. Statistical tests indicated that 106 proteins were significantly differentially abundant between the two EC lines, and that 35 were more abundant in the responsive genotype (EC line SE1) and 71 were more abundant in the blocked genotype (EC line SE6). An increase in the abundance of proteins related to cell defense, anti-oxidative stress responses, and storage reserve deposition was observed in SE1. Moreover, in SE6 we observed an increased abundance of two proteins associated with seed development during the embryogenic cell proliferation stage, which we suggest is associated with genotypes showing a low responsiveness to embryo formation. Differences in protein abundance between the EC lines are discussed in terms of carbohydrate metabolism, cell division, defense response, gene expression, and response to reactive oxygen species.

Carbohydrate-mediated responses during zygotic and early somatic embryogenesis in the endangered conifer, Araucaria angustifolia

“…It provides a reliable experimental system for investigating the regulatory mechanisms of embryo development [13,14]. Araucaria angustifolia , a native Brazilian conifer with considerable economic, ecological and social importance [15], has emerged as a model for investigating embryo development. This species is classified as critically endangered by the International Union of Conservation of Nature Red List of Threatened Species [16] and has recalcitrant seeds, resulting in rapid loss of viability [17].…”

“…angustifolia through somatic embryogenesis has not yet been developed. In part, this is due to insufficient knowledge of the underlying regulatory process that control embryogeneis in this species [15,22,23,24]. …”

“…angustifolia embryogenesis [23,24,25,26]. A notable exception is the role of carbohydrates, which has not been studied in detail, although transcriptome and proteome analyses suggest that several genes and proteins involved in carbohydrate metabolism are highly expressed during both zygotic and somatic embryo development [15,22]. In addition, while the importance of carbohydrate metabolism and nutrient availability for somatic embryo growth and development has been examined in other conifer species [11,13,27,28,29], a role for carbohydrates as signaling molecules during embryogenesis has not been established.…”

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

“…Apart from the aforementioned storage function of vicilins, they are also considered potential biomarkers for early selection of ECLs with high embryogenic potential with positive responsiveness to maturation conditions (dos Santos et al 2016). This fact is in agreement with our findings because EMs generated at 28°C were those with the highest amount of embryos developed at the end of maturation stage (García-Mendiguren et al 2015).…”

“…This event results in the synthesis of new mRNAs and proteins specific to the different stages through which embryo development proceeds (Chugh and Khurana 2002). In conifers, some efforts have recently been made to describe SE development at the molecular level (Jo et al 2014) and differences in proteins abundance between cell lines with contrasting embryogenic potential have been found (dos Santos et al 2016). Proteomic studies combining two-dimensional (2D) gel electrophoresis with a high degree of accuracy in protein identification by mass spectrometry (MS), are available for Cupressus sempervirens (Sallandrouze et al 1999), Picea glauca (Lippert et al 2005), Larix×eurolepis (Teyssier et al 2014) and other conifers as it was reviewed by Abril et al (2011).…”