Quantitative levels of Deficiens and Globosa during late petal development show a complex transcriptional network topology of B function.

The transcriptional network topology of B function in Antirrhinum, required for petal and stamen development, is thought to rely on initial activation of transcription of DEFICIENS (DEF) and GLOBOSA (GLO), followed by a positive autoregulatory loop maintaining gene expression levels. Here, we show that the mutant compacta (co), whose vegetative growth and petal size are affected, plays a role in B function. Late events in petal morphogenesis such as development of conical cell area and scent emissions were reduced in co and def (nicotianoides) (def (nic) ), and absent in co def (nic) double mutants, suggesting a role for CO in petal identity. Expression of DEF was down-regulated in co but surprisingly GLO was not affected. We investigated the levels of DEF and GLO at late stages of petal development in the co, def (nic) and glo-1 mutants, and established a reliable transformation protocol that yielded RNAi-DEF lines. We show that the threshold levels of DEF or GLO required to obtain petal tissue are approximately 11% of wild-type. The relationship between DEF and GLO transcripts is not equal or constant and changes during development. Furthermore, down-regulation of DEF or GLO does not cause parallel down-regulation of the partner. Our results demonstrate that, at late stages of petal development, the B function transcriptional network topology is not based on positive autoregulation, and has additional components of transcriptional maintenance. Our results suggest changes in network topology that may allow changes in protein complexes that would explain the fact that not all petal traits appear early in development. © 2012 The Authors. The Plant Journal © 2012 Blackwell Publishing Ltd.

Citation

María Manchado-Rojo, Luciana Delgado-Benarroch, María J Roca, Julia Weiss, Marcos Egea-Cortines. Quantitative levels of Deficiens and Globosa during late petal development show a complex transcriptional network topology of B function. The Plant journal : for cell and molecular biology. 2012 Oct;72(2):294-307

Mesh Tags

Substances

PMID: 22708513

search → result