The INHIBITOR OF MERISTEM ACTIVITY (IMA) protein

Abstract

The INHIBITOR OF MERISTEM ACTIVITY (IMA) gene The meristem activity is intimately linked to hormonal growth from tomato regulates the processes of flower and ovule develop- ment.1 IMA encodes a Mini Zinc Finger (MIF) protein that is characterized by a very short sequence containing an unusual zinc- finger domain. IMA acts as a repressor of WUSCHEL expression which controls the meristem organizing centre and the determi- nacy of the nucellus during ovule development. IMA inhibits cell proliferation during floral termination, controls the number of carpels during floral development and participates in the initiation of ovule primordia by activating D-type gene expression. In addi- tion IMA is involved in a multiple hormonal signalling pathway like its Arabidopsis homolog MIF1. We thus propose that IMA, as a representative of this new family of zinc finger proteins, is an important effector in the regulatory pathway controlling meristem activity linking cell division, differentiation and hormonal control of development.