Zygnematophyceae

Zygnematophyceae (or Conjugatophyceae) is a class of green algae in the division Charophyta,[2] consisting of more than 4000 described species.[3] It contains the order Zygnematales. The Desmidiales emerged within the Zygnematales.[4] The Zygnematophyceae are the sister clade of the Mesotaenium, together forming the sister clade of the land plants.[5][6][7] The body plan of Zygnematophyceae is simple, and appear to have gone through a secondary loss of morphological complexity.[8] They contain genes involved in protection from desiccation that appear to have been derived by horizontal gene transfer from bacteria; the genes are found in plants, Zygnematophyceae, bacteria, but no other organisms. The genes may have helped to enable plants to make the transition to life on land.[9][10]

Zygnematophyceae
Conjugation in Spirogyra.
Scientific classification
Domain:
Eukaryota
(unranked):
Archaeplastida
Kingdom:
Plantae
Division:
Charophyta/Streptophyta
Class:
Zygnematophyceae

Round, 1971
Orders

Zygnematales

Synonyms[1]
  • Akontae Blackman & Tansley, 1902
  • Conjugatophyceae Engler, 1892
  • 'Conjugatae' Engler, 1892
  • Gamophyceae
  • Saccodermae Pascher ex Kossinskaja, 1952
  • Zygnemaphyceae Round 1971
  • Zygophyceae Widder, 1960

Sexual reproduction in the Zygnematophyceae takes place through a process called conjugation.[11] Here cells or filaments of opposite gender line up, and tubes form between corresponding cells. The male cells then become amoeboid and crawl across the female, or sometimes both cells crawl into the connecting tube. The cells then meet and fuse to form a zygote, which later undergoes meiosis to produce new cells or filaments. As in plants, only the female passes its chloroplasts on to the offspring.

References
  1. Guiry, M.D. (2013). "Taxonomy and nomenclature of the Conjugatophyceae (=Zygnematophyceae)". Algae. 28 (1): 1–29. doi:10.4490/algae.2013.28.1.001. hdl:10379/11755.
  2. Gontcharov, A. A. (2003-12-05). "Are Combined Analyses Better Than Single Gene Phylogenies? A Case Study Using SSU rDNA and rbcL Sequence Comparisons in the Zygnematophyceae (Streptophyta)". Molecular Biology and Evolution. 21 (3): 612–624. doi:10.1093/molbev/msh052. ISSN 0737-4038. PMID 14739253.
  3. Molecular and morphological diversity of Zygnema and Zygnemopsis (Zygnematophyceae, Streptophyta) from Svalbard (High Arctic)
  4. Lemieux, Claude; Otis, Christian; Turmel, Monique (2016). "Comparative Chloroplast Genome Analyses of Streptophyte Green Algae Uncover Major Structural Alterations in the Klebsormidiophyceae, Coleochaetophyceae and Zygnematophyceae". Frontiers in Plant Science. 7: 697. doi:10.3389/fpls.2016.00697. ISSN 1664-462X. PMC 4877394. PMID 27252715.
  5. Wickett, Norman J.; Mirarab, Siavash; Nguyen, Nam; Warnow, Tandy; Carpenter, Eric; Matasci, Naim; Ayyampalayam, Saravanaraj; Barker, Michael S.; Burleigh, J. Gordon (2014-11-11). "Phylotranscriptomic analysis of the origin and early diversification of land plants". Proceedings of the National Academy of Sciences. 111 (45): E4859–E4868. Bibcode:2014PNAS..111E4859W. doi:10.1073/pnas.1323926111. ISSN 0027-8424. PMC 4234587. PMID 25355905.
  6. de Vries, Jan; Stanton, Amanda; Archibald, John M.; Gould, Sven B. (2016-02-16). "Streptophyte Terrestrialization in Light of Plastid Evolution". Trends in Plant Science. 0 (6): 467–476. doi:10.1016/j.tplants.2016.01.021. ISSN 1360-1385. PMID 26895731.
  7. Gitzendanner, Matthew A.; Soltis, Pamela S.; Wong, Gane K.-S.; Ruhfel, Brad R.; Soltis, Douglas E. (2018). "Plastid phylogenomic analysis of green plants: A billion years of evolutionary history". American Journal of Botany. 105 (3): 291–301. doi:10.1002/ajb2.1048. ISSN 0002-9122. PMID 29603143.
  8. from The Chara Genome - ScienceDirect.com
  9. Zimmer, Carl. "How did plants conquer land? These humble algae hold clues". The New York Times.
  10. Cheng, Shifeng; Xian, Wenfei; Fu, Yuan; Marin, Birger; Keller, Jean; Wu, Tian; Sun, Wenjing; Li, Xiuli; Xu, Yan; Zhang, Yu; Wittek, Sebastian; Reder, Tanja; Günther, Gerd; Gontcharov, Andrey; Wang, Sibo; Li, Linzhou; Liu, Xin; Wang, Jian; Yang, Huanming; Xu, Xun; Delaux, Pierre-Marc; Melkonian, Barbara; Wong, Gane Ka-Shu; Melkonian, Michael (2019). "Genomes of Subaerial Zygnematophyceae Provide Insights into Land Plant Evolution". Cell. 179 (5): 1057–1067.e14. doi:10.1016/j.cell.2019.10.019. ISSN 0092-8674. PMID 31730849.
  11. Kapraun DF (April 2007). "Nuclear DNA Content Estimates in Green Algal Lineages: Chlorophyta and Streptophyta". Ann. Bot. 99 (4): 677–701. doi:10.1093/aob/mcl294. PMC 2802934. PMID 17272304.


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