OVEREXPRESSION OF A CBM ON Arabidopsis thaliana CELL WALL INCREASES PLANT RESISTANCE TO Botrytis cinerea

CRISTINA F. NARDI; NATALIA VILLARREAL; FRANCO ROSSI; GUSTAVO MARTINEZ; MARCOS CIVELLO

Chascomús

Congreso; SAB; 2013

A carbohydrate binding module (CBM) is a contiguous amino acid sequence within a carbohydrate-active enzyme that provides the ability to bind cell wall polysaccharides. Most of cell wall enzymes contain CBMs. Here we present an approach to modified the cell wall by overexpressing a strawberry (Fragaria x ananassa) EXPANSIN 2 CBM (CBMFaEXP2) in Arabidopsis cell wall. In order to direct the CBM to the secretory pathway, a fusion was made between CBMFaEXP2 and the signal peptide of AtEXP8. Once transgenic plants were obtained, the subcellular localization was confirmed by confocal microscopy. Real Time PCR assays revealed that expression levels of a number of genes involved in cell wall catabolism were down-regulated in transgenic plants regarding wild type (WT). Considering that in a previous work we reported that overexpression of CBMFaEXP2 confers an increase in total cell wall content and in cell wall thickness; the resistance of CBM-expressing plants to B. cinerea was evaluated. Results showed a significant decrease of the necrotic area in transgenic plants after inoculation in comparison to WT. We conclude that overexpression of CBMFaEXP2 alters cell wall genes expression and increases resistance to damage caused by the necrotrophic fungus B. cinerea.