Cloning and functional analysis of the proximal promoter region of FaEXP2 gene in strawberry fruit.

DOTTO MC; STEPHENS C; MARTÍNEZ GA; CIVELLO PM; VALPUESTA V

Mar del Plata, Buenos Aires Argentina

Congreso; XLIII Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB); 2007

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB)

Studies of promoter regions of ripening specific genes are highly relevant due to their biotechnological implications in fruit quality improvement. Knowledge of either promoter strength or the length of its best regulatory regions is therefore essential. Transient expression systems allow a fast analysis especially valuable in fruits like strawberry. Expansins are cell wall proteins that have been related to fruit softening. FaEXP2 is a strawberry expansin gene whose expression is fruit specific and its hormonal regulation has not been determined yet. No promoter region of a strawberry expansin gene had been described until this report. In order to find the possible hormones in control of the expression of this gene and to characterize an expansin promoter, we isolated a 650 bp fragment of the promoter region of FaEXP2 gene. The prediction of cis-acting regulatory element was performed using PLACE and PlantCARE databases. Deletions of the promoter fragment were constructed in pGL3 Basic vector, fruit discs were transiently transformed by the biolistic method and luciferase activity was detected in protein extracts using a luminometer. Regulatory elements in response to light (G-box; I-box) and hormones (GARE y ABRE) were predicted. By transient transformation we determined that two fragments of 650 pb and 500 pb have the elements required to conduct satisfactory gene expression.