PSEUDOFILAMENTOUS GREEN ALGAE FORM INDEPENDENT CHLOROPHYTE AND STREPTOPHYTE LINEAGES

• Published in: Journal of phycology Vol. 36; no. s3; pp. 8 - 9
• Main Authors: Buchheim, Buchheim, J.A.
• Format: Journal Article
• Language: English
• Published: Boston, MA, USA Blackwell Science Inc 01.12.2000
• Subjects: Chlorophyta; Geminella; Gloeotila; Hazenia; Interfilum; Microspora; Sphaeroplea
• ISSN: 0022-3646; 1529-8817
• DOI: 10.1046/j.1529-8817.1999.00001-24.x

The pseudofilamentous condition in green algae has been characterized as the formation of a linear array of autospores. Although it is likely that this characterization will be found to be an over‐simplification, it serves as a logical starting point for a study of diversity among pseudofilamentous taxa. Therefore, given that molecular phylogenetic analyses have revealed that coccoid, autospore‐formers are found in a number of independent green algal lineages, it is reasonable to expect that pseudofilamentous taxa are likely to be found in a number of distinct lineages. In order to test this hypothesis, data from the nuclear‐encoded 18S r  RNA gene were collected from several pseudofilamentous, green algal genera (Geminella, Gloeotila, Hazenia, Interfilum, Microspora, and Sphaeroplea) and incorporated into an 18S rRNA database of chlorobiont taxa. Results from phylogenetic analyses of these data support (1) an alliance of Interfilum, two Geminella isolates, and Klebsormidium within the streptophyte lineage, (2) an alliance of two Geminella isolates and Microspora as a sister group to the ulvophycean/chlorophycean/trebouxiophycean clade or as a sister group to trebouxiophycean taxa, (3) an alliance of Hazenia with ulotrichalean taxa, (4) of Gloeotila with trebouxiophycean taxa and (5) an alliance of Sphaeroplea with chlorophycean taxa. These data confirm that the filamentous condition has evolved in a number of independent lineages. Moreover, these data further illustrate that the extent of molecular variability within the green algae is far from fully appreciated.