The codA transgene for glycinebetaine synthesis increases the size of flowers and fruits in tomato.

The tolerance of various species of plant to abiotic stress has been enhanced by genetic engineering with certain genes. However, the use of such transgenes is often associated with negative effects on growth and productivity under non-stress conditions. The codA gene from Arthrobacter globiformis is of particular interest with respect to the engineering of desirable productive traits in crop plants. The expression of this gene in tomato plants resulted in significantly enlarged flowers and fruits under non-stress conditions. The enlargement of flowers and fruits was associated with high levels of glycinebetaine that accumulated in reproductive organs, such as flower buds and fruits. The enlargement of flowers was related to an increase in the size and number of cells, and reflected the pleiotropic effect of the codA transgene on the expression of genes involved in the regulation of cell division.