Developmental gene regulation during tomato fruit ripening and in-vitro sepal morphogenesis

Here, we have further examined regulation of putative developmental genes possibly involved in tomato fruit ripening and development. Using molecular biological methods, we have determined the relative abundance of various transcripts of genes during in vitro sepal ripening and in tomato fruit pericarp at three stages of development. A number of transcripts show similar expression in fruits to RIN and PSY1, ripening-associated genes, and others show quite different expression.Our investigation has resulted in confirmation of some of our previous database mining results and has revealed differences in gene expression that may be important for tomato cultivar variation. We present new and intriguing information on genes that should now be studied in a more focused fashion.Red ripe (RR) tomatoes, appealing to the eye as well as the palate, are the result of numerous physiological changes controlled by hormonal, environmental, and developmental signals, causing maturation or differentiation of various fruit tissues simultaneously. These physiological changes affect the visual, textural, flavor, and aroma characteristics to make fruit more appealing to potential consumers for dispersal of seed. One hormonal cue, ethylene evolution, active at the onset of the respiratory burst during ripening in this climacteric fruit, has been scrutinized in detail over the years [1,2]. Transgenic tomato plants, expressing antisense genes for ethylene biosynthesis enzymes, show that ethylene is necessary for tomato fruit ripening [3]. However, something must signal ethylene induction before the climacteric ethylene burst. Because 1-aminocyclopropane-1-carboxylic acid synthase (ACCS), an enzyme involved in ethylene biosynthesis, is induced before the onset of ethylene evolution, it seems reasonable to assume that other factors control early developmental stages of ripening fruit [4,5]. E8, a gene of unknown function, is expressed in the rin mutant, which does not exhibit the climacteric b