The genus Closterium, a new model organism to study sexual reproduction in streptophytes

Abstract

Contents Summary99I.Introduction99II.Life cycle of Closterium100III.Sexual reproductive processes in the heterothallic Closterium peracerosum‐strigosum‐littorale complex101IV.Homothallism in the C. psl. complex102V.Sexual reproduction and inheritance of mating types in Closterium ehrenbergii102VI.mt‐determining gene of the C. psl. complex103VII.Future perspectives103Acknowledgements103References103 Summary Closterium occupies a key phylogenetic position as an ancestor of land plants and is the best‐characterized Charophycean alga in terms of the process of sexual reproduction. Zygospores form as a result of sexual reproduction between genetically determined mating type plus (mt+) and mating type minus (mt−) cells in heterothallic strains, or between clonal cells in homothallic strains. Here we review knowledge on the intercellular communication and mating type determination for successful sexual reproduction in Closterium. Using genomic information and transgenic techniques, the genus could be a model organism to study the mechanisms and evolution of sexual reproduction in streptophytes.

Asymmetric mating behavior of isogamous budding yeast

“…Even the well-investigated example of brown alga Ectocarpus, where similarly sized gametes exhibit clear behavioral asymmetry, might be explained by mild but significant bias in both size and relative abundance of the two different gametes (mild anisogamy) and by the ancestor of Ectocarpus being anisogamous (6,7). Nevertheless, different responses to mating pheromones could potentially lead to asymmetries between gametes even in isogamous organisms, such as those observed in the green alga Closterium (8) or in the diatom Seminavis robusta (9,10).…”

Switching it up: algal insights into sexual transitions

“…Gametophyte-dominant land plants such as the bryophytes Marchantia polymorpha, Ceratodon purpureus, Physcomitrella patens (Chang et al 2016) and green algae such as volvocines, Closterium, Chara braunii, Ulva sp. (Nishiyama et al 2018;De Clerck et al 2018;Tsuchikane and Sekimoto 2019;Umen and Coelho 2019;Bringloe et al Communicated by Frederic Berger.…”

“…Gametophyte-dominant land plants such as the bryophytes Marchantia polymorpha , Ceratodon purpureus , Physcomitrella patens (Chang et al 2016 ) and green algae such as volvocines, Closterium, Chara braunii , Ulva sp. (Nishiyama et al 2018 ; De Clerck et al 2018 ; Tsuchikane and Sekimoto 2019 ; Umen and Coelho 2019 ; Bringloe et al 2020 ) offer alternative systems to help answer questions on the mechanisms and evolution of sexual reproductive modes. In particular, some algae show comparable diversity and frequency of shifts in reproductive modes as land plants (Hanschen et al 2018 ; Heesch et al 2019 ; Tsuchikane and Sekimoto 2019 ).…”

“…(Nishiyama et al 2018 ; De Clerck et al 2018 ; Tsuchikane and Sekimoto 2019 ; Umen and Coelho 2019 ; Bringloe et al 2020 ) offer alternative systems to help answer questions on the mechanisms and evolution of sexual reproductive modes. In particular, some algae show comparable diversity and frequency of shifts in reproductive modes as land plants (Hanschen et al 2018 ; Heesch et al 2019 ; Tsuchikane and Sekimoto 2019 ). The diversity of reproductive systems in algae frame is important topic in a complementary way, and their elucidation will help generate a more balanced perspective on the origins and evolution of plant reproductive modes and provide more data for testing evolutionary theories about sex.…”

Regeneration and transient gene expression in protoplasts of Draparnaldia (chlorophytes), an emerging model for comparative analyses with basal streptophytes

“…Although it is generally accepted that land plants evolved from freshwater streptophyte algae, their key properties enabling such a transition are still poorly understood [1–5 and citations therein]. To examine these properties several basal land plant and streptophyte algal models, such as Anthoceros [6], Chara [7] , Closterium [8] , Klebsormidium [9], Marchantia [10], Mougeotia [11] and Physcomitrella [12] are (or are currently being) established. However, there are also many chlorophytes (a sister lineage to streptophyte algae and land plants) that moved to terrestrial habitats and morphologically even resemble mosses.…”