Intercellular transport and plant development
Plant cells are joined by a relatively rigid cell wall that provides structural and mechanical support but restricts cell-to-cell communication. Plasmodesmata are channels embedded in the cell wall that connect the cytoplasm of neighbouring cells providing a path for short- and long- distance intercellular transport. Proteins, metabolites, RNAs, viral proteins among others move through plasmodesmata to regulate development and the plant response to the environment. Plasmodesmata are also the gateways for the vascular network that allows systemic spreading of nutrients and signalling molecules around the plant.
Despite their importance, we understand very little about plasmodesmata structural and functional organization, which remains one of the outstanding challenges in plant biology. Our research investigates the composition and regulation of these channels. Specifically, the role of the cell wall in regulating channel aperture, the environmental and developmental signals and signalling pathways affecting channel structure and permeability and the importance of plasmodesmata in the formation and maintenance of apical and lateral meristems.
Identification and characterization of novel proteins and signalling pathways affecting plasmodesmata regulation. We are assessing the intracellular localization of selected proteins identified in a proteomic screen of plasmodesmata-enriched cell walls (Fernandez-Calvino et al., 2011) using fluorescence approaches. Confirmed PD-proteins are being characterized using mutants and overexpression lines. Their regulation in response to developmental and environmental signals provide information about cues affecting intercellular transport.
Determining the importance of plasmodesmata regulation in the plant response to oxidative signalling. Past research revealed the role of reactive oxygen species in Plasmodesmata regulation (Benitez-Alfonso et al., 2009). Now, we are dissecting the mechanism underlying this regulation and identifying their importance in the plant response to oxidative stress environments.
Dissecting the role of plasmodesmata in root organogenesis. The importance of regulating plasmodesmata during the initiation and development of lateral root primordia has recently emerged (Benitez-Alfonso et al., 2013). We are currently investigating signalling pathways affecting the expression of plasmodesmata proteins and the formation of symplastic domains in this process. We are also applying the knowledge and tools obtained in Arabidopsis to analyse the influence of plasmodesmata in the formation of a symbiotic nodule.
Characterization of the properties of the cell wall surrounding Plasmodesmata. The accumulation of the polymer callose (β-1,3 glucans) in the cell wall constricts the channel aperture, modulating intercellular molecular flux. We are closely studying the proteins involved directly and indirectly in the metabolism of callose at plasmodesmata (Gaudioso-Pedraza and Benitez-Alfonso, 2014; Knox and Benitez-Alfonso, 2014). We are also dissecting the contribution of other cell wall components in regulating channel structure/aperture.