Cell-to-cell trafficking patterns in cell lines of Araucaria angustifolia (Brazilian pine) with contrasting embryogenic potential

Abstract

The acquisition of embryogenic competence involves aspects at a cellular level related to cell communication and signaling. For Araucariaangustifolia, transcriptome and proteome databases have indicated differential gene expression and protein abundance related to cell-to-cell communication during embryogenesis. The differences are mainly related to vesicular transport and regulation of plasmodesmata region-related proteins. This study aims to understand the behavior of cell-to-cell communication in cell cultures with contrasting embryogenic potential. We used two embryogenic cell lines of A. angustifolia (Responsive and Blocked) and carried out gene expression, coexpression network, immunocytochemical, and ultrastructural analyses. Eight proteins related to vesicular transport and cell-to-cell communication processes were identified with a significantly different abundance in both cell lines. One callose hydrolase (AaGHL17) was differentially expressed between the two cell lines. Accordingly, we used immunocytochemistry and found a higher intensity of callose in the Responsive, as opposed to the Blocked embryogenic cells. Transmission Electron Microscopy images highlighted a more intense vesicular activity in the Responsive cell line compared to the Blocked one. Different status of cell-to-cell intercommunication and vesicular transport is associated with somatic embryogenic competence.