The NTT transcription factor promotes replum development in Arabidopsis fruits

[EN] Fruits are complex plant structures that nurture seeds and facilitate their dispersal. The Arabidopsis fruit is termed silique. It develops from the gynoecium, which has a stigma, a style, an ovary containing the ovules, and a gynophore. Externally, the ovary consists of two valves, and their margins lay adjacent to the replum, which is connected to the septum that internally divides the ovary. In this work we describe the role for the zinc-finger transcription factor NO TRANSMITTING TRACT (NTT) in replum development. NTT loss of function leads to reduced replum width and cell number, whereas increased expression promotes replum enlargement. NTT activates the homeobox gene BP, which, together with RPL, is important for replum development. In addition, the NTT protein is able to bind the BP promoter in yeast, and when this binding region is not present, NTT fails to activate BP in the replum. Furthermore, NTT interacts with itself and different proteins involved in fruit development: RPL, STM, FUL, SHP1 and SHP2 in yeast and in planta. Moreover, its genetic interactions provide further evidence about its biological relevance in replum development.The Col-0 Arabidopsis 5-kb pBP-GUS line was kindly provided by S. Hake (Plant Gene Expression Center, U. S. Department of Agriculture-Agricultural Research Service, Plant and Microbial Biology Department, University of California at Berkeley, Berkeley, USA). The 1-kb pBP-GUS line was kindly provided by M. Timmermans (Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, USA). Lines N104422 (ntt-3) and N3161 (bp) were provided by NASC (http://arabidopsis.info) and A. Chalfun Jr. (Department of Biology, Federal University of Lavras, Minas Gerais, Brazil) pACTII was provided by S. E. Elledge. pYFN43 and pYFC43 were provided by A. Ferrando. The EST for NTT (FB085 g05) was provided by the Kazusa DNA Research Institute. We thank S. Dixit for making the NTT-GUS construct. The work in the Marsch-Martinez laboratory was supported by the National Council of Science and Technology of Mexico (CONACyT, grant 165986), and work in the de Folter laboratory was supported by CONACyT grants 82826 and 177739. Furthermore, S. d. F. and C. F. acknowledge the support of the European Union FP7 project EVOCODE (grant 247587).Marsch Martínez, N.; Zuñiga Mayo, VM.; Herrera Ubaldo, H.; Ouwerkerk, PB.; Pablo Villa, J.; Lozano Sotomayor, P.; Greco, R.... (2014). The NTT transcription factor promotes replum development in Arabidopsis fruits. Plant Journal. 80(1):69-81. https://doi.org/10.1111/tpj.12617S698180