Role of the male germ line for the alternation of generations

• Applicant: Professor Dr. Sven B. Gould, since 6/2022
• Subject Area: Plant Cell and Developmental Biology ; Evolution and Systematics of Plants and Fungi ; Plant Genetics and Genomics
• Term: since 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 440411476

The alternation of generations of plants was coined middle of the 19th century by Hofmeister and describes the haplodiplontic life cycle of all land plants, with two multicellular phases: the haploid gametophyte and the diploid sporophyte. Early in the 20th century Bower hypothesized that this peculiar life cycle evolved from the haplontic life cycle of streptophyte algae (sister to land plants) via intercalation of mitosis before meiosis occurs, at the zygotic stage. Flowering plants, and with them the prime plant model, Arabidopsis, possess a drastically reduced gametophytic generation that is difficult to assess experimentally. Moreover, flowering plants have secondarily lost motile (flagellated) spermatozoids and replaced it by pollen. In this proposal, we want to study the role of the male germ line (spermatozoids) for the alternation of generations. For that, we are employing bryophyte model organisms that possess motile spermatozoids, and have easily tractable gametophytic and sporophytic generations. The proposal is based on our preliminary work that has unrooted several candidate genes involved in the male germ line, and addresses two questions of relevance for MAdLand: “How did embryogenesis and the alternation of generations evolve?” and “Which features enabling conquest of land evolved in charophyte freshwater algae?”. The project involves comparative studies of bryophytes, charophytes and seed plants and is expected to further our understanding of the evolution of the plant male germ line and the alternation of generations.

• DFG Programme: Priority Programmes
• Subproject of: SPP 2237: MAdLand — Molecular Adaptation to Land: plant evolution to change
• Ehemaliger Antragsteller: Professor Dr. Stefan A. Rensing, until 6/2022