DNA-protein interactions regulating the degradation of cell wall during Aerenchyma development in roots of sugarcane

Abstract

Mechanisms incurring in degradation of plant cell wall polysaccharides are quite frequent, given that it is an important barrier to the entry of pathogens and is it also an obstacle to the physical expansion, cell division and differentiation of a tissue. In many physiological events the cell wall has to be modified to enable structural changes typical of each event. The study of these processes is quite appealing, since it combines the possibility of analyzing the regulatory mechanisms of gene expression and exploring plant glycosyl hydrolases intended to degrade their own wall. There is a series of events comprised as soon as the cell receives a signal to degrade its cell wall until the moment in which it recruits an array of glycosyl hydrolases. It corresponds to a valuable opportunity to explore how the plant cell operates in a way synchronized and reciprocal with its surrounding environment, as for how these signals are interpreted and how the response is executed. Our group has characterized the cell wall degradation during the aerenchyma formation in roots of sugarcane, which is an important tool to advance the knowledge of degradative enzymes for the second generation bioethanol production. Our results demonstrated that as the aerenchyma develops on the root, the transcriptional activity of glycosyl hydrolases and transcription factors genes respond to a complex auxin-ethylene balance. The co-transcriptional profile of both genes and evidences from the literature and evidence points to a direct interaction of these regulators on the expression of genes of glycoside hydrolases. The analysis of the expression pattern led to the identification of target genes for sequencing. The investigation of putative glycosyl hydrolases promoter region revealed the presence of cis elements possibly recognized by the DNA binding domains identified in the transcription factor of interest. The confirmation of the functionality of the regions predicted in silico are goals of this project. Results demonstrating the interaction of ethylene response factors and promoters of genes encoding for glycosyl hydrolases are practically absent in the literature and represent an important link between hormone signaling and cell wall degradation in the developing model of the aerenchyma formation. (AU)