A MADS-Box Gene Necessary for Fruit Ripening at the Tomato Ripening-Inhibitor ( Rin ) Locus

Tomato plants harboring the ripening - inhibitor ( rin ) mutation yield fruits that fail to ripen. Additionally, rin plants display enlarged sepals and loss of inflorescence determinacy. Positional cloning of the rin locus revealed two tandem MADS-box genes ( LeMADS - RIN and LeMADS - MC ), whose expression patterns suggested roles in fruit ripening and sepal development, respectively. The rin mutation alters expression of both genes. Gene repression and mutant complementation demonstrate that LeMADS - RIN regulates ripening, whereas LeMADS - MC affects sepal development and inflorescence determinacy. LeMADS - RIN demonstrates an agriculturally important function of plant MADS-box genes and provides molecular insight into nonhormonal (developmental) regulation of ripening.