TDR4 might mediate tomato fruit development

BUSI MV, BUSTAMANTE CA, 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)

The FRUITFULL (FUL) gene encodes a MADS-box protein that has previously been shown to be required for carpel and fruit development in Arabidopsis thaliana. The ful mutation affects several aspects of plant development. The most dramatic effect is observed within the carpel where, from stage 12, the valve cells fail to elongate and differentiate and the replum cells growth with and altered morphology. The lack of coordinated growth of the fruit tissues leads to crowded fruits, a failure of dehiscence and, frequently, the premature rupture of the carpel valves. TDR4 of Licopersicon esculentum shares high similarity in sequence to FUL. According to our RT-PCR and in-situ hybridization results, TDR4 mRNA is first detected at stage 0 of flower development. It is then detected at high levels shortly after or at anthesis showing a peak (phase I) and diminishing to phase II. Thus, FUL and TDR4 show similar bimodal expression patterns. To know if they could be considered ortholog genes, an antisense strategy in Arabidopsis thaliana was performed. Phenotypic analyses of these plants expressing antisense TDR4 gene showed small and crowded fruits (reduced by 70 % in size) with small seeds and diminished fresh weight. So, TDR4 is sufficiently homologue to FUL to diminishe its expression and both should be putative orthologue. TDR4 might exert an important function during tomato fruit development. Efforts to express it ectopically in Arabidopsis thaliana are currently being made.