Poster Presentation International Plant Molecular Biology Conference 2024

Novel role for SHATTERPROOF MADS-box transcription factors in seed coat mucilage formation (#135)

Rebecca E Carra 1 , Maheshika Herath 1 , Debra R David 1 , Tanping Huang 1 , John F Golz 1
  1. University of Melbourne, Parkville, VIC, Australia

In myxospermous species such as Arabidopsis (Arabidopsis thaliana), exposure of the mature seed coat to water causes the seed coat to release a polysaccharide-rich gel known as seed coat mucilage. Production of mucilage during seed coat development is governed by a gene regulatory network composed of transcription factors that are arranged into a hierarchy1. Previous work has shown that mutations in two closely related MADS-box transcription factors SHATTERPROOF1 (SHP1) and SHATTERPROOF2 (SHP2) have a mucilage release defect, although the nature of these defects has not been studied2. SHP1 and SHP2 are closely related to SEEDSTICK (STK), which has a well-characterised role in mucilage production3. As STK and SHP1/SHP2 work together during ovule development4, it is possible that these transcription factors perform similar roles in the developing seed coat. Using a combination of phenotypic and molecular analyses, SHP1/SHP2 are identified as regulators of genes associated with mucilage regulation, synthesis, and modification, and it is demonstrated that the function of SHP1/SHP2 differs from STK. Additionally, we present preliminary work suggesting SHP1/SHP2 expression is controlled by the upstream regulators DE1-BINDING FACTOR1 (DF1) and MYB61. These results suggest that the function of SHP1/SHP2 and STK diverges following fertilisation and that they control different aspects of mucilage production/modification. As well as providing insight into the role of MADS-box transcription factors during seed coat development, these results identify new interactions between transcription factors within the gene regulatory network controlling the production of seed coat mucilage. 

 

  1. Golz JF, Allen PJ, Li SF, Parish RW, Jayawardana NU, Bacic A and Doblin MS (2018) Layers of regulation – Insights into the role of transcription factors controlling mucilage production in the Arabidopsis seed coat. Plant Science. 272, 179–192.
  2. Ehlers K, Bhide AS, Tekleyohans DG, Wittkop B, Snowdon RJ and Becker A (2016) The MADS Box Genes ABS, SHP1, and SHP2 Are Essential for the Coordination of Cell Divisions in Ovule and Seed Coat Development and for Endosperm Formation in Arabidopsis thaliana. PLoS One. 11 (10), e0165075.
  3. Ezquer I, Mizzotti C, Nguema-Ona E, Gotté M, Beauzamy L, Viana VE, Dubrulle N, de Oliveira AC, Caporali E, Koroney AS, Boudaoud A, Driouich A and Colombo L (2016) The Developmental Regulator SEEDSTICK Controls Structural and Mechanical Properties of the Arabidopsis Seed Coat. Plant Cell. 28, 2478–2492.
  4. Favaro R, Pinyopich A, Battaglia R, Kooiker M, Borghi L, Ditta G, Yanofsky MF, Kater MM and Colombo L (2003) MADS-Box Protein Complexes Control Carpel and Ovule Development in Arabidopsis. Plant Cell. 15, 2603–2611.