Phymatolithopsis gen. nov. (Hapalidiales, Corallinophycidae, Rhodophyta) based on molecular and morpho-anatomical evidence.

A multigene (psbA, rbcL, 18S rDNA) molecular phylogeny of the genus Phymatolithon showed a polyphyletic grouping of two monophyletic clades within the Hapalidiales. DNA sequence data integrated with morpho-anatomical comparisons of type material and of recently collected specimens were used to establish Phymatolithopsis gen. nov. with three species, P. prolixa comb. nov., the generitype, P. repanda comb. nov. and P. donghaensis sp. nov. Phymatolithopsis is sister to Mesophyllum and occurs in a clade distinct from Phymatolithon and boreal species currently assigned to Lithothamnion. Morpho-anatomically, Phymatolithopsis is comprised of species that are non-geniculate and encrusting, bear epithallial cells with rounded walls (not flared), subepithallial initials that are usually as short as or shorter than their immediate inward derivatives, conceptacle primordia from all stages forming superficially directly from subepithallial initials, mature carposporangial conceptacles with a discontinuous fusion cell, gonimoblast filaments that develop at the margins of the fusion cell around the periphery of the carposporangial conceptacle chambers, and multiporate tetra/bisporangial conceptacles. Phymatolithopsis can be distinguished from Phymatolithon by the origin of its conceptacle primordia, which are initiated superficially, directly from the layer of subepithallial initials below the epithallial cells and the distribution of gonimoblast filaments in carposporangial conceptacles, that are at the margins of the fusion cells.

Protoplast isolation from Dictyopteris pacifica and Scytosiphon lomentaria, using a simple commercial enzyme preparation.

BACKGROUND: Protoplasts (i.e., naked plant cells) can be used for in vitro manipulations and genetic improvement in cultivars with economic value. During the last decade, protoplast research in economic brown algae has been scarce, and it is usually hampered by the use of non-commercial enzymes or crude extracts for isolating protoplasts. Dictyopteris pacifica is part of a brown algal genus well known by its wide chemical diversity and biological properties. Scytosiphon lomentaria is an edible brown seaweed with antioxidant, antitumor, and antiviral properties. So far, there are no protoplast isolation protocols using commercial enzymes for these two economic brown algae. In this study, we obtained protoplasts from cultured samples of D. pacifica and S. lomentaria using commercially available enzymes. Additionally, we investigated the effects of Driselase inclusion and Ca-chelation pre-treatment on protoplast yields in order to optimize the conditions for protoplast preparations. RESULTS: Protoplasts were isolated from Dictyopteris pacifica and Scytosiphon lomentaria using the commercially available Cellulase Onozuka RS (1%) and Alginate lyase (4 U mL-1), and short incubation time (4 h). Driselase did not show significant effects on protoplast production in both species. Ca-chelation pre-treatment only increased the number of protoplasts in D. pacifica. Under optimal conditions, the protoplast yields from D. pacifica and S. lomentaria were 4.83 ± 2.08 and 74.64 ± 32.49 × 106 protoplasts g-1 fresh weight, respectively. The values obtained for S. lomentaria were 2-3 orders of magnitude higher than previously reported. CONCLUSIONS: Our results show that high protoplast yields can be obtained from D. pacifica and S. lomentaria using a simple mixture of commercial enzymes (Cellulase RS and Alginate lyase) and short incubation time (4 h). This work also represents the first report of protoplast isolation in D. pacifica. The method proposed here can help to expand protoplast technology in more brown algal species.

Corallinapetrales and Corallinapetraceae: A new order and family of coralline red algae including Corallinapetra gabrielii comb. nov.

The coralline algal genus Corallinapetra is currently monospecific and was established on the species Corallinapetra novaezelandiae, known from a single collection from north-eastern New Zealand. On the basis of multi-gene phylogenetic analyses, Corallinapetra has been resolved apart from all currently recognized families and orders within the Corallinophycidae. We analyzed DNA sequence data from the holotype of Lithothamnion gabrielii, which has been considered a heterotypic synonym of L. muelleri, and an unidentified sample collected from Stewart Island in New Zealand, using psbA, rbcL, and COI-5P genes. We also observed detailed morpho-anatomical characters with light and scanning electron microscopy. Our phylogenetic analyses showed that L. gabrielii and the sample from New Zealand belonged to the same clade as Corallinapetra, distinct from other families and orders in the Corallinophycidae. Members of this clade are distinguishable from other families and orders in the Corallinophycidae by possessing sporangia that are surrounded by remnant sterile filaments that are weakly calcified in mature multiporate sporangial conceptacles that produce zonately divided tetrasporangia. Therefore, we propose that Corallinapetra be placed in its own family, Corallinapetraceae and order, Corallinapetrales, and that L. gabrielii should be assigned to Corallinapetra, as C. gabrielii, to reflect their phylogenetic relationships. We also obtained a partial rbcL sequence data from the lectotype of L. muelleri, the generitype of Lithothamnion. Comparison of the L. muelleri type sequence with L. gabrielii unambiguously demonstrated that these two species are not conspecific, and confirm the placement of L. muelleri within the Hapalidiales.

Wilsonosiphonia gen. nov. (Rhodomelaceae, Rhodophyta) based on molecular and morpho-anatomical characters.

Morphological, anatomical, and molecular sequence data were used to assess the establishment and phylogenetic position of the genus Wilsonosiphonia gen. nov. Phylogenies based on rbcL and concatenated rbcL and cox1 loci support recognition of Wilsonosiphonia gen. nov., sister to Herposiphonia. Diagnostic features for Wilsonosiphonia are rhizoids located at distal ends of pericentral cells and taproot-shaped multicellular tips of rhizoids. Wilsonosiphonia includes three species with diagnostic rbcL and cox1 sequences, Wilsonosiphonia fujiae sp. nov. (the generitype), W. howei comb. nov., and W. indica sp. nov. These three species resemble each other in external morphology, but W. fujiae is distinguished by having two tetrasporangia per segment rather than one, W. indica by having abundant and persistent trichoblasts, and W. howei by having few and deciduous trichoblasts.

MORPHOLOGICAL AND MOLECULAR CHARACTERIZATION OF SPECIES OF THE GENUS CENTROCERAS (CERAMIACEAE, CERAMIALES), INCLUDING TWO NEW SPECIES(1).

Centroceras clavulatum (C. Agardh) Montagne is widely reported as being a prime example of a cosmopolitan red algal species. Instead, C. clavulatum is here determined as restricted to northern Chile, Peru, southern California, southern Australia, and New Zealand. Specimens identified using the current species concept for "C. clavulatum" fall into nine morphological groups that correspond to highly supported clades in phylogenetic analyses. Three of these clades correspond to the resurrected species Centroceras gasparrinii (Meneghini) Kützing, C. hyalacanthum Kützing, and C. micracanthum Kützing. Two others are recognized as new species: Centroceras rodmanii sp. nov. from southern Chile, which is characterized by hooked spines arranged in a whorl at the node, a spine or flattened gland cell cut off from the first cortical initials, and a single acropetal cortical cell issued from the second cortical initials; and C. tetrachotomum sp. nov. from South Africa, which has a tetrachotomous branching pattern, straight spines in a whorl, an acropetal cortical cell and a spine or a flattened gland cell cut off from the first cortical initials, and a two-celled acropetal filament cut off from the second cortical initials. Three additional species from South Africa are also recognized as distinct species. All phylogenetic analyses of the rbcL gene, LSU rDNA, and SSU rDNA were consistent with the vegetative and tetrasporangial morphological distinctions, thus supporting the resurrection of three species and the description of two new species.