Hecatomb: Studying the central role of HECATE in the specificatiOn of Multiple plant reproductive Boundaries

For succesful plant reproduction, including seed dispersal, highly specialized tissues form and orchestrate the sequential steps from gametogenesis to seed germination. It is clear that plant reproduction is not only fundamental to the fitness of plant species, but also the basis of the entire agricultural economy, since most of the agricultural activities begin with seed and end with seed. In this context, it is crucial to understand the genetic networks underlying the differentiation of these specialized tissues and their function. Only a deep knowledge of these networks may allow the optimization of agricultural practices, the biotechnological improvement of crop beneficial traits and the design and adoption of strategies for conservation of biological diversity.

In HECATOMB we aim to contribute to the field with the study of HECATE3 (HEC3) across flowering plants. HEC3 encodes a transcription factor well studied in Arabidopsis thaliana, but for which limited functional information is available in other species. We have generated a significant body of preliminary results in Arabidopsis, Oryza sativa and Nicotiana benthamiana that indicate that HEC3 has a highly conserved role in regulating the development of key traits for plant reproduction success and of high agronomic interest: the formation of the stigma and the transmitting tract tissues, and the specification of the dehiscence zone in anthers and fruits.

In the context of this general goal, we want to address the following specific questions:

1. Do the hec3 mutants share morphological and functional defects in the species under study? Can we explain the differences in the hec3 phenotypes by the differential morphology and development of the tissues under study or by different effects of hec3 mutations in the development of these analogous tissues?

2. What are the genes regulated by HEC3? Are there common elements in separation processes (anther/fruit/seed dehiscence)? How is the network for stigma development? Are there also common elements in separation processes and stigma development?

3. What is the basis for selectivity of HEC3 downstream targets? How is this modulated by protein-protein interactions? Are these interactions conserved? Why hec3 ind mutants do not have anther indehiscence in Arabidopsis? Has the subfunctionalization of HEC3 and IND been complemented by the neofunctionalization of additional genes?

4. How is HECATE regulated in these different tissues? Can we separate HEC3 roles by manipulating its expression?

5. Can we translate this knowledge to crop improvement? Can we engineer specifically fruit indehiscence and anther indehiscence and/or manipulate stigma and transmitting tract performance?

Ministerio de Ciencia, Innovación y Universidades

Agencia Estatal de Investigación

MICIU/FEDER. RTI2018-099239-B-I00.