Regulation of expression of two novel flower‐specific genes from tomato (Solanum lycopersicum) by gibberellin

Two flower‐specific cDNAs have been isolated after differential screening of an anther cDNA library. This library was constructed 48 h after GA3 treatment of buds of the GA‐deficient gib‐1 mutant of tomato. Northern blot analysis during flower development in tomato demonstrated that the expression of both genes is regulated by gibberellins (GAs). Application of GA3 to developmentally arrested gib‐1 flower buds induced new expression of tgas100 mRNA 48 h post‐treatment, while an increased accumulation of tgas105 mRNA was found after 8 h. In situ analyses showed the spatial distribution of the expression of both genes within the tomato flower. One of the deduced polypeptides (TGAS105) displays similarities to cysteine‐rich extensin‐like proteins, while the other (TGAS100) shows significant homology with a stamen‐specific gene of Antirrhinum majus. Based on the deduced protein sequences, the possible function of the encoded proteins is discussed.