The expression of several cell wall-related genes in Arabidopsis roots is down-regulated under boron deficiency

Plant cell wall is a dynamic structure that is of fundamental importance in plant growth and development, as well as in the response to environmental stresses. There is direct evidence for a role of boron (B) in cross-linking of cell wall rhamnogalacturonan II (RG-II) and pectin assembly, which shows that B is essential for cell wall structure and function. The aim of the present work was to investigate the effects of B deficiency on the expression of cell wall-related genes in Arabidopsis roots. For this purpose, plants were grown hydroponically in a nutrient solution supplemented with 2 mu M B and then transferred to a boron-free medium for 6 and 24 h. A transcriptome analysis was carried out and several cell wall-related genes were identified, whose expressions were down-regulated by B deficiency. These genes belong to arabinogalactan protein, xyloglucan endotransglycosylase/hydrolase, polygalacturonase, pectate lyase, pectin methylesterase, expansin, and cellulose synthase-like gene families. These results suggest that in addition to the essential role that B plays in the structural organization of the cell wall, it could directly or indirectly have an impact on the expression levels of genes related to the cell wall. (C) 2007 Elsevier B.V. All rights reserved.