Project Details
Projekt
On the origin of the seed habit II: reverse genetics of MADS-box genes in Ceratopteris
Applicant
Professor Dr. Günter Theißen
Subject Area
Plant Genetics and Genomics
Evolution and Systematics of Plants and Fungi
Plant Cell and Developmental Biology
Evolution and Systematics of Plants and Fungi
Plant Cell and Developmental Biology
Term
since 2021
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 431732981
The ultimate goal of our project is to better understand the proximate mechanisms that brought about seeds during evolution. During the course of this work we want to clarify the molecular mechanisms, especially innovations in gene regulatory networks, that were involved in the origin of ovules and seeds. We will pursue our goal by studying the molecular developmental genetics of reproduction in the fern model system Ceratopteris richardii. As a fern, C. richardii is a member of the monilophytes, which represent the closest living relatives of extant seed plants (flowering plants and gymnosperms). We will pursue our goal in two independent ways, a ‘targeted candidate gene approach’, and an ‘unbiased transcriptomic approach’. In the candidate gene approach we study the function of six MIKCC-type MADS-box genes in C. richardii. Close relatives of these genes control crucial aspects of reproductive development in flowering plants, including ovule and seed development. We hypothesize that the MADS-box genes that we have chosen have related functions in C. richardii. To test our hypothesis, we will use methods of reverse genetics, harnessing methodology that we have established in the previous phase of the project. In one approach we will knockout these six genes, individually and in some combinations, employing the genome editing tools of CRISPR-Cas9. In a parallel approach we will overexpress the genes in C. richardii under the control of a strong promoter. The mutant phenotypes of both the knockout and overexpressing plants will provide complementary insights into the function of the six genes in ferns and their potential role during the origin of the seed. In addition, we will study the interaction of MADS-domain proteins from diverse land plant species, including C. richardii, with the transcriptional co-regulators LUG and SEU in an evolutionary context, employing Electrophoretic Mobility Shift Assays (EMSA). In the transcriptomics approach we will evaluate data about the differential expression of genes at several developmental stages throughout the life-cycle of C. richardii that we have gathered in the previous phase of the project. We will compare these data with those of diverse seed plants, mosses and liverworts. This analysis will allow us to identify differences in reproductive gene regulatory networks between major taxa of land plants. The recognized differences will then enable us to identify critical changes in regulatory genes during the origin of the seed in evolution.
DFG Programme
Research Units
