Biodiversity and Plant SystematicsDr. Anja Schmidt
Plant reproduction and seed formation are not only crucial steps in the life cycle of higher plants, but plant seeds are of great importance for human and animal nutrition. In higher plants, apart from sexual reproduction, also asexual reproduction through seeds (apomixis) has been described in ~400 species. This is scientifically fascinating from a developmental and evolutionary point of view. Furthermore, apomixis has an outstanding potential for applications in agriculture, as it leads to the formation of clonal offspring. Therefore, an engineering of apomixis in crops would allow the fixation of complex and heterozygous high yielding genotypes over several subsequent generations. As a precondition for targeted manipulation of crop seed formation, a precise understanding of the underlying genetic basis and molecular programs is required.
To gain an understanding of the gene regulatory programs governing the formation and development of plant reproductive tissues, we are combining laser assisted microdissection with RNA-Seq for transcriptome analyses at high spatial and temporal resolution. As model systems, we are using Arabidopsis thaliana and sexual and apomictic accessions of the closely related genus Boechera. This has recently identified a number of new candidate genes for apomixis and substantiated previous evidence of RNA helicases to be crucial for development of the reproductive lineages in plants, resembling conserved features of animal germlines. Interestingly, the coding regions of many RNA helicases remain highly conserved and under purifying selection also in apomicts, in agreement with their importance in fundamental cellular or developmental processes. In support of this notion, we recently uncovered crucial roles of different novel RNA helicases for germline development. Importantly, we demonstrated that in Arabidopsis lines carrying mutant alleles of a single RNA helicase, RH17, show phenotypes resembling different elements of apomixis. We further identified additional RNA helicases causing severe defects during reproductive development. Current directions aim at the elucidation of the molecular processes and regulatory networks they are involved in to control aspects of gene activity, genome integrity, and stress response during reproductive development.
Selected recent publications
- Stein RE, Nauerth BH, Binmöller L, Zühl L, Loreth A, Reinert M, Ibberson D, Schmidt A. (2021). RH17 acts in repression of reproductive fate and autonomous seed coat development in Arabidopsis. Development, 148 (19):dev.198739.
- Kiefer M, Nauerth BH, Volkert C, Ibberson D, Loreth A, Schmidt A. (2020) Gene function rather than reproductive mode drives the evolution of RNA helicases in sexual and apomictic Boechera. Genome Biol Evol. 12(5):656-673.
- Schmidt A. (2020) Controlling apomixis: Shared features and distinct characteristics of gene regulation. Genes 11(3):329.
- Zühl L, Volkert C, Ibberson D, Schmidt A. (2019) Differential activity of F-box genes and E3 ligases distinguishes sexual versus apomictic germline specification in Boechera. J. Exp. Bot. 70(20):5643-5657. doi: 10.1093/jxb/erz323.