Major changes in the cell wall during silique development in Arabidopsis thaliana.

Fruit development is a highly complex process, which involves major changes in plant metabolism leading to cell growth and differentiation. Changes in cell wall composition and structure play a major role in modulating cell growth. We investigated the changes in cell wall composition and the activities of associated enzymes during the dry fruit development of the model plant Arabidopsis thaliana. Silique development is characterized by several specific phases leading to fruit dehiscence and seed dispersal. We showed that early phases of silique growth were characterized by specific changes in non-cellulosic sugar content (rhamnose, arabinose, xylose, galactose and galacturonic acid). Xyloglucan oligosaccharide mass profiling further showed a strong increase in O-acetylated xyloglucans over the course of silique development, which could suggest a decreased capacity of xyloglucans to be associated with each other or to cellulose. The degree of methylesterification, mediated by the activity of pectin methylesterases (PMEs), decreased over the course of silique growth and dehiscence. The major changes in cell wall composition revealed by our analysis suggest that it could be major determinants in modulating cell wall rheology leading to growth or growth arrest.