Proteomic Identification of Differentially Altered Proteins During Regeneration from Nodular Cluster Cultures in Vriesea reitzii (Bromeliaceae)

Abstract

Tissue culture techniques have been employed for bromeliad mass propagation by means of the morphogenetic route of nodular cluster cultures (NC), which exhibit high regenerative potential. This study aimed to identify proteins differentially altered during the regeneration of shoots from NC in the bromeliad Vriesea reitzii. Proteomic analysis was performed by two-dimensional electrophoresis and MALDI-TOF mass spectrometry. Image analysis from NC, microshoots and shoots resulted in the detection of 345, 482, and 209 protein spots, respectively. Proteins related to the stress response (catalase, probable l-ascorbate peroxidase 3 and heat shock protein 81-1) and amino acid metabolism (glutamine synthetase, 4-hydroxy-tetrahydrodipicolinate reductase 1, serine hydroxymethyltransferase 1 and 14-3-3-like protein GF14-F) and other proteins (elongation factor Ts, probable signal peptidase complex subunit 2, calcium-dependent protein kinase 23, and ubiquitin-like protein-NEDD8-like protein RUB3) exhibited increased abundance in the early stages of development. On the other hand, proteins related to carbohydrate metabolism (ribulose bisphosphate carboxylase/oxygenase activase, ribulose bisphosphate carboxylase, and phosphoglycerate kinase 1) and ATP synthesis (ATP synthase subunit alpha and ATP synthase subunit beta) exhibited increased abundance in later stages. Changes in proteins related to cellular metabolic processes, the assembly of the photosynthetic mechanism, the response to medium stress and the dynamics of the cell cytoskeleton contribute to a high regenerative potential, which characterizes NC. To our knowledge, this is the first proteomic analysis performed during the regeneration process from NC in bromeliads. This study may provide important insights into proteins and cellular events involved in the micropropagation of this group of plants.