Cellular expansion: more than a game of forces

GRISOLIA, M.J.; BARCHIESI, J.; PERALTA, D.A.; PEROTTI, V.; GOMEZ-CASATI, D.F; BUSI, M.V.

Mar del Plata, Buenos Aires

Encuentro; VIII Encuentro Latinoamericano y del Caribe de Biotecnología REDBIO-Argentina 2013; 2013

REDBIO

CBMs (carbohydrate binding modules) are structures associated to catalytic domains, which have the ability to bind to different polysaccharides. Among these, those with a strong affinity for starch (SBD) have an evolutionary advantage due to the presence of two substrate-binding sites. In order to modify the plant cell wall to make more flexible, we have fused the SSIII (AT1G11720) SBD to the signal peptide of EXPA8 (AT2G40610), and targeted to the cell wall of Arabidopsis plants. Transgenic plants showed an increased size, due to an increment in cell expansion, and a thinning of the cell wall. Interestingly, we observed an alteration in transient starch composition (amylose/amylopectin) ratio, but not in the leaf starch total content. Furthermore, we performed phenotypic, metabolomics, transcriptomic and proteomic studies in order to interpret the relationship between the two metabolisms, and we found evidence suggesting that hormone regulation could be involved in this phenomenon. The results suggest that the tested methodology can be useful in generating better substrates for livestock feed or bioenergy.