TÍTULO: Secondary Cell Walls: from Outside to Inside
PALESTRANTE: Zheng Li -University of Melbourne
DATA: 06.06.18
HORÁRIO: 14H
LOCAL: Anfiteatro AG da Botânica - IB/USP

Abstract
Secondary cell walls (SCWs) are essential for plant growth and development. They also provide textiles, timber and other materials for human use. The identification of several master switches of the SCW transcriptional regulatory network enables us to readily study changes in transcriptional, metabolic and posttranscriptional events during SCW formation, and to integrate these data into a systems biology based framework. In this study, this was done by using a hormone-inducible transcription factor driven system of the SCW master switch VND7. The data has revealed the coordination of a number of metabolic processes and gene activities in the SCW development. Cellulose, the major secondary wall constituent, is synthesized by plasma membrane-localized cellulose synthases (CesAs) whose catalytic activity propels them through the membrane. We show that the protein CELLULOSE SYNTHASE INTERACTING1 (CSI1)/POM2 is necessary to align the secondary wall CesAs and MTs during the initial phase of xylem vessel development in Arabidopsis thaliana and rice (Oryza sativa). Surprisingly, these MT-driven patterns successively become imprinted and sufficient to sustain the continued progression of wall thickening in the absence of MTs and CSI1/POM2 function. Hence, two complementary principles underpin wall patterning during xylem vessel development.