SHATTERPROOF MADS-box genes control seed dispersal in Arabidopsis

The fruit, which mediates the maturation and dispersal of seeds, is a compl ex structure unique to flowering plants. Seed dispersal in plants such as A rabidopsis occurs by a process called fruit dehiscence, or pod shatter. Few studies(1-3) have focused on identifying genes that regulate this process, in spite of the agronomic value of controlling seed dispersal in crop plan ts such as canola(4,5). Here we show that the closely related SHATTERPROOF (SHP1) and SHATTERPROOF2 (SHP2) MADS-box genes are required for fruit dehis cence in Arabidopsis. Moreover, SHP1 and SHP2 are functionally redundant, a s neither single mutant displays a novel phenotype. Our studies of shp1 shp 2 fruit, and of plants constitutively expressing SHP1 and SHP2, show that t hese two genes control dehiscence zone differentiation and promote the lign ification of adjacent cells. Our results indicate that further analysis of the molecular events underlying fruit dehiscence may allow genetic manipula tion of pod shatter in crop plants.