Viridiplantae Explained

Viridiplantae constitute a clade of eukaryotic organisms that comprises approximately 450,000–500,000 species that play important roles in both terrestrial and aquatic ecosystems.^[1] They include the green algae, which are primarily aquatic, and the land plants (embryophytes), which emerged from within them.^{[2] [3] [4]} Green algae traditionally excludes the land plants, rendering them a paraphyletic group. However it is accurate to think of land plants as a kind of alga. Since the realization that the embryophytes emerged from within the green algae, some authors are starting to include them.^{[5] [6] [7] [8] [9]} They have cells with cellulose in their cell walls, and primary chloroplasts derived from endosymbiosis with cyanobacteria that contain chlorophylls a and b and lack phycobilins. Corroborating this, a basal phagotroph archaeplastida group has been found in the Rhodelphydia.^[10]

In some classification systems, the group has been treated as a kingdom,^[11] under various names, e.g. Viridiplantae, Chlorobionta, or simply Plantae, the latter expanding the traditional plant kingdom to include the green algae. Adl et al., who produced a classification for all eukaryotes in 2005, introduced the name Chloroplastida for this group, reflecting the group having primary chloroplasts with green chlorophyll. They rejected the name Viridiplantae on the grounds that some of the species are not plants, as understood traditionally.^[12] The Viridiplantae are made up of two clades: Chlorophyta and Streptophyta as well as the basal Mesostigmatophyceae and Chlorokybophyceae.^{[13] [14]} Together with Rhodophyta and glaucophytes, Viridiplantae are thought to belong to a larger clade called Archaeplastida or Primoplantae.

Phylogeny and classification

Simplified phylogeny of the Viridiplantae, according to Leliaert et al. 2012.^[15]

• Viridiplantae
  • Chlorophyta
    • core chlorophytes
      • Ulvophyceae
        • Cladophorales
        • Dasycladales
        • Bryopsidales
        • Trentepohliales
        • Ulvales-Ulotrichales
        • Oltmannsiellopsidales
      • Chlorophyceae
        • Oedogoniales
        • Chaetophorales
        • Chaetopeltidales
        • Chlamydomonadales
        • Sphaeropleales
      • Trebouxiophyceae
        • Chlorellales
        • Oocystaceae
        • Microthamniales
        • Trebouxiales
        • Prasiola clade
      • Chlorodendrophyceae
        • Chlorodendrales
      • Pedinophyceae^[16]
    • prasinophytes (paraphyletic)
      • Pyramimonadales
      • Mamiellophyceae
      • Pycnococcaceae
      • Nephroselmidophyceae
      • Prasinococcales
      • Palmophyllales
• Streptophyta
  • • • • Charophytes Mesostigmatophyceae
      • Mesostigmatales
      • Chlorokybales
    • Klebsormidiophyceae
    • Phragmoplastophyta
      • Charophyceae
      • Coleochaetophyceae
      • Zygnematophyceae
      • Embryophyta (land plants)

Cladogram

In 2019, a phylogeny based on genomes and transcriptomes from 1,153 plant species was proposed.^[17] The placing of algal groups is supported by phylogenies based on genomes from the Mesostigmatophyceae and Chlorokybophyceae that have since been sequenced. Both the "chlorophyte algae" and the "streptophyte algae" are treated as paraphyletic (vertical bars beside phylogenetic tree diagram) in this analysis.^{[18] [19]} The classification of Bryophyta is supported both by Puttick et al. 2018,^[20] and by phylogenies involving the hornwort genomes that have also since been sequenced.^{[21] [22]}

Ancestrally, the green algae were flagellates.

Notes and References

1. Michael Deyholos. Leebens-Mack JH, Barker MS, Carpenter EJ, Deyholos MK, Gitzendanner MA, Graham SW, etal . One Thousand Plant Transcriptomes Initiative . One thousand plant transcriptomes and the phylogenomics of green plants . Nature . 574 . 7780 . 679–685 . October 2019 . 31645766 . 6872490 . 10.1038/s41586-019-1693-2 .
2. Cocquyt E, Verbruggen H, Leliaert F, Zechman FW, Sabbe K, De Clerck O . Gain and loss of elongation factor genes in green algae . BMC Evolutionary Biology . 9 . 39 . February 2009 . 19216746 . 2652445 . 10.1186/1471-2148-9-39 . free .
3. Book: Becker B . Function and evolution of the vacuolar compartment in green algae and land plants (Viridiplantae) . 264 . 1–24 . 2007 . 17964920 . 10.1016/S0074-7696(07)64001-7 . 9780123742636 . International Review of Cytology . registration .
4. Kim E, Graham LE . EEF2 analysis challenges the monophyly of Archaeplastida and Chromalveolata . PLOS ONE . 3 . 7 . e2621 . July 2008 . 18612431 . 2440802 . 10.1371/journal.pone.0002621 . 2008PLoSO...3.2621K . Redfield . Rosemary Jeanne . vanc . free .
5. Delwiche CF, Timme RE . Plants . Current Biology . 21 . 11 . R417–22 . June 2011 . 21640897 . 10.1016/j.cub.2011.04.021 . free .
6. Web site: Charophycean Green Algae Home Page. www.life.umd.edu. 2018-02-24.
7. Ruhfel BR, Gitzendanner MA, Soltis PS, Soltis DE, Burleigh JG . From algae to angiosperms-inferring the phylogeny of green plants (Viridiplantae) from 360 plastid genomes . BMC Evolutionary Biology . 14 . 23 . February 2014 . 24533922 . 3933183 . 10.1186/1471-2148-14-23 . free .
8. Delwiche CF, Cooper ED . The Evolutionary Origin of a Terrestrial Flora . Current Biology . 25 . 19 . R899–910 . October 2015 . 26439353 . 10.1016/j.cub.2015.08.029 . free .
9. Parfrey LW, Lahr DJ, Knoll AH, Katz LA . Estimating the timing of early eukaryotic diversification with multigene molecular clocks . Proceedings of the National Academy of Sciences of the United States of America . 108 . 33 . 13624–9 . August 2011 . 21810989 . 3158185 . 10.1073/pnas.1110633108 . 2011PNAS..10813624P . free .
10. Bowles . Alexander M. C. . Williamson . Christopher J. . Williams . Tom A. . Lenton . Timothy M. . Donoghue . Philip C. J. . 2022-10-31 . The origin and early evolution of plants . Trends in Plant Science . 28 . 3 . 312–329 . English . 10.1016/j.tplants.2022.09.009 . 1360-1385 . 36328872. 10871/131900 . 253303816 . free .
11. Web site: Viridiplantae . 2009-03-08.
12. Adl SM, Simpson AG, Farmer MA, Andersen RA, Anderson OR, Barta JR, Bowser SS, Brugerolle G, Fensome RA, Fredericq S, James TY, Karpov S, Kugrens P, Krug J, Lane CE, Lewis LA, Lodge J, Lynn DH, Mann DG, McCourt RM, Mendoza L, Moestrup O, Mozley-Standridge SE, Nerad TA, Shearer CA, Smirnov AV, Spiegel FW, Taylor MF . 6 . The new higher level classification of eukaryotes with emphasis on the taxonomy of protists . The Journal of Eukaryotic Microbiology . 52 . 5 . 399–451 . 2005 . 16248873 . 10.1111/j.1550-7408.2005.00053.x . 8060916 . free .
13. Simon A, Glöckner G, Felder M, Melkonian M, Becker B . EST analysis of the scaly green flagellate Mesostigma viride (Streptophyta): implications for the evolution of green plants (Viridiplantae) . BMC Plant Biology . 6 . 2 . February 2006 . 16476162 . 1413533 . 10.1186/1471-2229-6-2 . free .
14. Sánchez-Baracaldo P, Raven JA, Pisani D, Knoll AH . Early photosynthetic eukaryotes inhabited low-salinity habitats . Proceedings of the National Academy of Sciences of the United States of America . 114 . 37 . E7737–E7745 . September 2017 . 28808007 . 5603991 . 10.1073/pnas.1620089114 . 2017PNAS..114E7737S . free .
15. Leliaert F, Smith DR, Moreau H, Herron MD, Verbruggen H, Delwiche CF, De Clerck O . 2012 . Phylogeny and molecular evolution of the green algae . 10.1080/07352689.2011.615705 . Critical Reviews in Plant Sciences . 31 . 1 . 1–46 . 2012CRvPS..31....1L . 17603352 .
16. Marin B . Nested in the Chlorellales or independent class? Phylogeny and classification of the Pedinophyceae (Viridiplantae) revealed by molecular phylogenetic analyses of complete nuclear and plastid-encoded rRNA operons . Protist . 163 . 5 . 778–805 . September 2012 . 22192529 . 10.1016/j.protis.2011.11.004 .
17. Leebens-Mack . M. . Barker . M. . Carpenter . E. . Michael Deyholos . Deyholos . M. K. . Gitzendammer . M. A. . Graham . S.W. . Grosse . I. . Li . Zheng . 3 . One thousand plant transcriptomes and the phylogenomics of green plants . Nature . 574 . 7780 . 2019 . 679–685 . 10.1038/s41586-019-1693-2 . 31645766 . 6872490 . free .
18. Liang . Zhe . etal . Mesostigma viride Genome and Transcriptome Provide Insights into the Origin and Evolution of Streptophyta . Advanced Science . 7 . 1 . 2019 . 1901850 . 10.1002/advs.201901850 . 31921561 . 6947507 . free .
19. Wang . Sibo . etal . Genomes of early-diverging streptophyte algae shed light on plant terrestrialization . Nature Plants . 6 . 2 . 2020 . 95–106 . 10.1038/s41477-019-0560-3 . 31844283 . 7027972 . free .
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21. Zhang . Jian . etal . The hornwort genome and early land plant evolution . Nature Plants . 6 . 2 . 2020 . 107–118 . 10.1038/s41477-019-0588-4. 32042158 . 7027989 . free .
22. Li . Fay Wei . etal . Anthoceros genomes illuminate the origin of land plants and the unique biology of hornworts . Nature Plants . 6 . 3 . 2020 . 259–272 . 10.1038/s41477-020-0618-2. 32170292 . 8075897 . free .