Proteome changes during the germination and early seedling development of carnauba palm (Copernicia prunifera) under skotomorphogenic conditions

We analyze the proteome changes during the development of the carnauba palm (Copernicia prunifera) seedlings under skotomorphogenic conditions, by separating the embryo into its two components: haustorium (HA) and cotyledonary petiole (CP) and established the descriptive and quantitative proteomes of these tissues across four developmental stages. 5205 proteins were identified in HA and 6028 in CP. These proteomes are rich in proteins known to maintain the skotomorphogenic state, and in a complete set of proteins involved in cellular respiration and biosynthesis of secondary metabolites. The quantitative analysis employing a label-free approach revealed that 583 proteins in HA and 383 in CP were differentially abundant, with 251 proteins shared between the datasets. The results showed that HA participates in the digestion of food reserves present in HA itself and in the endosperm, acting as a conduit of nitrogen and carbon sources for the growing embryo axis. Among the differentially abundant proteins in the CP, we identified the presence of proteins from the cellular metabolism and proteins involved in the hydrolysis of food reserves such as starch and proteins. This indicates that the CP, in addition to the endosperm and HA, serves as a source of food reserves for the embryo axis.

Significance

Our results also reveal the differential regulation of specific proteins involved in reactive oxygen species scavenging, cell wall remodeling, respiratory metabolism, and protein repair in seeds and seedlings of C. prunifera. These findings have broad implications for understanding the energy metabolism that drives the transition from seed to seedling.

For this study, we employed state-of-the-art proteomic techniques, including quantitative mass spectrometry and bioinformatic analysis, that allowed us to create a large dataset that will be a valuable resource for future research on the physiological and biochemical aspects of skotomorphogenesis, photomorphogenesis, and the transition between these states.