Frontiers in Plant Science (May 2020)

MADS-Box and bHLH Transcription Factors Coordinate Transmitting Tract Development in Arabidopsis thaliana

  • Maurizio Di Marzo,
  • Irma Roig-Villanova,
  • Eva Zanchetti,
  • Francesca Caselli,
  • Veronica Gregis,
  • Paola Bardetti,
  • Matteo Chiara,
  • Andrea Guazzotti,
  • Elisabetta Caporali,
  • Marta Adelina Mendes,
  • Lucia Colombo,
  • Martin M. Kater

DOI
https://doi.org/10.3389/fpls.2020.00526
Journal volume & issue
Vol. 11

Abstract

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The MADS-domain transcription factor SEEDSTICK (STK) controls several aspects of plant reproduction. STK is co-expressed with CESTA (CES), a basic Helix-Loop-Helix (bHLH) transcription factor-encoding gene. CES was reported to control redundantly with the brassinosteroid positive signaling factors BRASSINOSTEROID ENHANCED EXPRESSION1 (BEE1) and BEE3 the development of the transmitting tract. Combining the stk ces-4 mutants led to a reduction in ovule fertilization due to a defect in carpel fusion which, caused the formation of holes at the center of the septum where the transmitting tract differentiates. Combining the stk mutant with the bee1 bee3 ces-4 triple mutant showed an increased number of unfertilized ovules and septum defects. The transcriptome profile of this quadruple mutant revealed a small subset of differentially expressed genes which are mainly involved in cell death, extracellular matrix and cell wall development. Our data evidence a regulatory gene network controlling transmitting tract development regulated directly or indirectly by a STK-CES containing complex and reveal new insights in the regulation of transmitting tract development by bHLH and MADS-domain transcription factors.

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