Characterisation of TDR6 gene expressed during the tomato fruit development

BUSTAMANTE CA, BUSI MV, ZABALETA EJ

Carlos Paz, Córdoba. Argentina.

Congreso; XXXVIII Reunión de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB); 2002

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

MADS box genes in plants have been shown to play fundamental roles in flower development. Recent reports indicate that they are involved in other processes than flower development such as the establishment of developing embryos, seed coat and ultimately in root and fruit development. We have identified seven tomato MADS box genes that are highly expressed during the first steps of tomato fruit development. In this work, we are interested in characterizing one of them, tdr6 gene. RT-PCR analyses indicate that tdr6 is expressed during flower development. After anthesis its expression increases showing a peak at phase II of tomato fruit development. During phase III its expression diminishes but it is still detected apparently confined to developing seeds. In situ hybridization analyses show that tdr6 is expressed in the three inner whorls, petals, stamens and carpels. Tdr6 RNA is expressed at anthesis preferentially in ovules and ovary walls. After fertilization, the expression is confined to the endothelium in four-day fruits. Tdr6 transcript in not detected at phase III in any layer of pericarp. Tdr6 RNA is not detected in embryo in any stage of development. Yeast two-hybrid analyses reveal that TDR6 is not able to form homodimers but interacts with TDR4 and TAGL11 only in one direction. TDR6 does not transactivate. These results are important for a model of tomato fruit development.