TY - JOUR
T1 - Improved taxon sampling and multigene phylogeny of unicellular chlamydomonads closely related to the colonial volvocalean lineage Tetrabaenaceae-Goniaceae-Volvocaceae (Volvocales, Chlorophyceae)
AU - Nakada, Takashi
AU - Tsuchida, Yudai
AU - Tomita, Masaru
N1 - Funding Information:
We are grateful to Dr. Kazuyuki Miyaji (formerly Toho University), Mr. Masayuki Yamamoto (Mos Yamagata Co., Ltd.), Ms. Miki Yamamoto (Mos Yamagata Co., Ltd.), Mr. Hitoshi Otaki (Shonai Industrial Promotion Center), Dr. Tadashi Kurimoto (Keio University), and Mr. Sohei Tomizawa (formerly University of Tokyo) for assistance in sample collection, to Dr. Hisayoshi Nozaki (University of Tokyo) for help in cultivation, and to Mr. Hiroaki Abe, Mr. Yasuha Watanabe, Mr. Ryusei Doi, Mr. Satoshi Ikuta, Mr. Yuito Sugawara, Mr. Takahiro Terui, Mr. Reiji Abe, and Mr. Shunsuke Takahashi (formerly Research Assistants at the Institute for Advanced Biosciences, Keio University; also students at Tsuruoka Chuo High School) for technical support (HA and YW for sample isolation, RD, SI, YS, TT, and RA for molecular analysis, and ST for sample cultivation). This work was supported by grants from the Institute for Fermentation, Osaka, Japan (to TN), and Yamagata Prefectural Government and Tsuruoka City , Japan (to MT). Appendix A
PY - 2019/1
Y1 - 2019/1
N2 - In the green algal order Volvocales (Chlorophyceae), flagellate colonial forms have evolved at least four times. One of these colonial lineages, Tetrabaenaceae-Goniaceae-Volvocaceae (TGV), which belongs to the clade Reinhardtinia, is closely related to several unicellular chlamydomonads in the genera Chlamydomonas and Vitreochlamys. However, the unicellular sister of TGV has not been specified. Here, the largest ever 18S rRNA phylogenetic tree of Reinhardtinia was constructed including several newly isolated chlamydomonads, and a clade (core-Reinhardtinia) including 32 unicellular lineages and three colonial families were recognized. Interrelationships within core-Reinhardtinia were barely resolved in the tree, and therefore combined 18S-atpB-psaA-psaB-psbC-rbcL gene phylogenetic analyses were performed with selected representatives of 29 of the 32 unicellular lineages and three colonial families. The 29 unicellular lineages were clustered into five metaclades and an unassigned lineage; the metaclade that includes Chlamydomonas pila was resolved, with moderate support, as the sister clade to TGV. To examine possible biases from specific gene(s), long-branch taxa, and the heterogeneous base composition, phylogenetic analyses using several smaller data sets were also performed. Light microscopy of C. pila and its relatives indicated that any early steps towards colony evolution appeared after divergence of TGV from the C. pila lineage.
AB - In the green algal order Volvocales (Chlorophyceae), flagellate colonial forms have evolved at least four times. One of these colonial lineages, Tetrabaenaceae-Goniaceae-Volvocaceae (TGV), which belongs to the clade Reinhardtinia, is closely related to several unicellular chlamydomonads in the genera Chlamydomonas and Vitreochlamys. However, the unicellular sister of TGV has not been specified. Here, the largest ever 18S rRNA phylogenetic tree of Reinhardtinia was constructed including several newly isolated chlamydomonads, and a clade (core-Reinhardtinia) including 32 unicellular lineages and three colonial families were recognized. Interrelationships within core-Reinhardtinia were barely resolved in the tree, and therefore combined 18S-atpB-psaA-psaB-psbC-rbcL gene phylogenetic analyses were performed with selected representatives of 29 of the 32 unicellular lineages and three colonial families. The 29 unicellular lineages were clustered into five metaclades and an unassigned lineage; the metaclade that includes Chlamydomonas pila was resolved, with moderate support, as the sister clade to TGV. To examine possible biases from specific gene(s), long-branch taxa, and the heterogeneous base composition, phylogenetic analyses using several smaller data sets were also performed. Light microscopy of C. pila and its relatives indicated that any early steps towards colony evolution appeared after divergence of TGV from the C. pila lineage.
KW - Alga
KW - Chlamydomonas
KW - Colony evolution
KW - Multigene phylogeny
KW - Vitreochlamys
KW - Zoosporangium
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U2 - 10.1016/j.ympev.2018.09.013
DO - 10.1016/j.ympev.2018.09.013
M3 - Article
C2 - 30266459
AN - SCOPUS:85054051656
VL - 130
SP - 1
EP - 8
JO - Molecular Phylogenetics and Evolution
JF - Molecular Phylogenetics and Evolution
SN - 1055-7903
ER -