Lecture 2: Common red algal families in the vicinity
of Bocas del Toro:
Gracilariaceae
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Photo: O.Camacho Hadad & Anna Fricke
Gracilariaceae
Halymeniaceae
Rhodymeniaceae
family, ordinal level
vegetative structure: cellular
medulla
Gracilaria
terete sp.
Hydropuntia
mixed-sized cells
flat sp.
Solieriaceae
Gracilariaceae
Solieriaceae (Solieria)
loose filiform, or mixed
cellular-filiform medulla
Halymeniaceae (Cryptonemia)
2
1
2
3
1
-cortical unit of 3 surface cells
Conjunctor cells fuse with neighboring cells,
resulting in secondary pit connection formation
-inherently uniaxial
-uniaxial growth quickly disguised
-axial cells: same shape as medullary cells
Generic distinction:
-comparative post-fertilization events of female
reproductive system in establishment of
cystocarp: nature of fusions
- complexity of male reproductive system
Gracilaria intermedia cystocarps
pericarp
carposporangia
inner gonimoblast
cystocarp floor
medulla
Gracilaria: multinucleate tubular
nutritive cells to roof, to base
Gracilariopsis:
uninucleate
conjunctor
cells at base
“TAPPING
BACK”
Gracilariophila
(parasite)
Hydropuntia: multinucleate
tubular nutritive cells at base
of cystocarp
2
1
3
1
unfertilized female structure
-origin: 3-cortical unit again
-lower cell of unit = cell 1 = supporting cell cutting
off carpogonial branch initial
-cells 2 & 3 = nutritive cells of carpogonial branch
unit
unfertilized 2-celled carpogonial branches
-2-celled carpogonial branch on supporting cell
-straight trichogyne reaching thallus surface
-partly fusion of cortical nutritive cells to carpogonium
Partly fusion of neighboring cortical cells with
carpogonium; vegetative nuclei remain in unfused portion
-diploid zygote nucleus in uninucleate carpogonium;
-fused cortical cells = nutritive cells
-young carpospore-bearing filaments (gonimoblasts)
cut off from carpogonial fusion cell
Generic character:
How lower cells of young carpospore-bearing filaments
fuse back to multinucleate carpogonial fusion cell
young cystocarp:
Gracilariopsis
-very regular, progressive growth of carposporebearing filaments
Fusion of lower carposporophyte cells to vegetative
gametophytic cells
Gracilariopsis
Gracilaria: multinucleate tubular
nutritive cells to roof, to base
Gracilariopsis:
uninucleate
conjunctor
cells at base
“TAPPING
BACK”
Gracilariophila
(parasite)
Hydropuntia: multinucleate
tubular nutritive cells at base
of cystocarp
Gracilaria:
Gracilariopsis:
in
shallow
or deep
pits
superficial
Gracilariophila:
Hydropuntia:
male structures
in deep
pits, connecting
to vegetative
cells
Gurgel & Fredericq 2004 = rbcL phylogeny of the Gracilariaceae, Bayesian Tree.
Global Phylogeny of the Gracilariaceae
Bayesian Inferred Phylogeny
Gurgel & Fredericq 2004
A meaningful global phylogeny of the
Gracilariaceae and the evolutionary
patterns found in it could only be
obtained after reaching a dataset
composed of 35+ taxa
Before that, taxa sampling played a
major issue in obtaining stable and
meaningful phylogenies.
So, nowadays, when new taxa (i.e.
distinct rbcL DNA sequences) are
added to the global phylogeny they
do not change the overall topology.
Ready for final taxonomic conclusions.
Gurgel & Fredericq 2004
Bayesian Tree
Genera:
What has been established so far?
Gracilaria
97
Hydropuntia
94
‘New Genus’
G. beckeri
G. textorii
91
G. ornata
97
G. bursa-pastoris
G. cervicornis
G. tikvahiae
G. mammillaris
G. canaliculata
G. salicornia
75
G. gracilis
G. pacifica
G. acuelata
H. aff. changii
H. aff. changii
H. changii
H. crassissima
H. cornea
H. caudata
H.
secundata
89 H. perplexa
82
99
H. preissiana
H. edulis
H. rangiferina
H. millardetii
H. eucheumatoides
H. urvillei
G. tenuistipitata
G. tenuistipitata
G. tenuistipitata
G. tenuistipitata
G.
tenuistipitata
85
G. chilensis
G. chilensis
G. vermiculophylla
G. vermiculophylla
Gp. hommersandii (outgroup)
83
67
Sub-Genera:
Textorii-type
spermatangia
Verrucosa-type
spermatangia
Rounded
carposporophyte
Lobed
carposporophyte
Chilensis-type
spermatangia
‘Verrucosa’-type
spermatangia
Is high quality-agar (gel strength)
correlated to phylogeny?
Is there character congruence between
agar gel strength (phenotype) and
molecular-based phylogenies (haplotype)?
Can sound phylogenies identify
lineages characterized by high-quality
agar?
Gurgel & Fredericq 2004
69
54
52
92
99
74
G. beckeri SOUTH AFRICA
G. capensis SOUTH AFRICA
G. viellardii TAIWAN
G. spinulosa TAIWAN
G. sp . PHILIPPINES
79
G.
flabelliformis
VENEZUELA
85
G.occidentali s LA, USA
G. ornata PANAMA
96
G. textorii JAPAN
G. multipartita FRANCE
G. bursa-pastori s ITALY
97
89
G. apiculata VENEZUELA
88
G. domingensi s BRAZIL
G. cervicornis FL, USA
G. curtissae VENEZUELA
100
G. tikvahiae CANADA
98
G. lacinulat a VENEZUELA
G. damaecornis FL, USA
98
100 G. cuneata FL, USA
97
cuneata PANAMA
99 G.G.sp.
PANAMA
G. sp. VENEZUELA
94
G. sp. PANAMA
G. mammillaris LA, USA
G. sp. BRAZIL
100
G. intermedia VENEZUELA
100
G. venezuelensis FL, USA
73
G. canaliculata PHILIPPINES
G. salicornia PHILIPPINES
G. arcuata PHILIPPINES
G. gracilis ENGLAND
100
G. gracilis FRANCE
100
G. pacifica WA, USA
98 G. usneoide s MEXICO
G. crassissima PANAMA
100
G. cornea VENEZUELA
100
G.
caudata
FL, USA
100 G. secunda FL,
USA
95
G. edulis PHILIPPINES
G. preissiana AUSTRALIA
100
G. dentata GHANA
100 G. dentata
PHILIPPINES
G. eucheumatoides PHILIPPINES
100
G. urvillei i AUSTRALIA
G. tenuistipitata JAPAN
100
G. tenuistipitata VA, USA
G. chilensis CHILE
100
G. vermiculophylla
G. tenuistipitata
G. chilensis
(90% agar worldwide,
Zemke-White & Ohno 1999)
Proposed as a distinct genus
by Gurgel & Fredericq 2004
Agar Properties:
Yield
Gel Strength
3,6 Anhydro-galactose
Gelling Point
Boiling Point
( %, dw/dw )
( g. cm-2 )
( %, dw/dw )
( °C )
( °C )
Data in the Literature:
1st Source of Variation:
(in the Agar Properties)
Strain / population
‘Tissue’ / Thallus Age
Light Regime
Temperature
Life-cycle
Reproductive status
2nd Source of Variation: ≠ Methodologies (Whyte et al. 1984):
* Extraction: Standard vs. Alkali
* Strength: gel shape,
Ø and crosshead speed (plunger)
* 3,6 AG: Resorcinol vs. IR Spectrophotometer
Fred Gurgel, pers. comm
Searching for Phylogenetic Patterns of Native Gel Strengths
Sampling for Published Data:
• Obtain agar parameters for species for which we have
phylogenetic data (= rbcL DNA sequences).
• Select methodologies that reflect the algae’s most
natural conditions.
– Extraction: Standard (shredding  boiling 
gelling  freezing  thawing  washing)
– Strength method: 1.5% gels, 1.0 cm Ø plungers
• Minimize Method Variation
Total number of Papers Surveyed =
Total number of Papers Selected =
26
09
Fred Gurgel, pers. comm
800
Gel
Strength
600
(g. cm-2)
400
200
0
1
2
3
4
5
6
7
8
9
10
11
Number of species with comparable agar data
G. chilensis
Clade
Gracilariopsis
Clade
Gracilaria s. s.
Clade
Fred Gurgel, pers. comm
Conclusions
• RbcL-based phylogenies reevaluated character
evolution in the Gracilariaceae and inferred a
new classification for Gracilaria sensu lato.
• The G. chilensis-clade and the genus
Hydropuntia are reinforced as distinct taxa in
the Gracilaria complex.
• Based on a literature review, data suggest that
there is a strong correlation between phylogeny
and agar gel strength (agar quality) between
genera, and between average genetic
divergence and gel strength values within each
genus.
ordinal & family-level characters:
-based on how unfertilized female system develops
in relation to vegetative growth
cf. Kylin system
Gracilaria: multinucleate tubular
nutritive cells to roof
Gracilariophila
(parasite)
Gracilariopsis:
uninucleate
conjunctor
cells
Hydropuntia: multinucleate
tubular nutritive cells at base
of cystocarp
Problem:
*differentiate among stages that are are
functional, versus abortive??
*no auxiliary cells!
Gracilaria: male structure development
Gracilaria: male structure development
Gracilaria: male structure development
Gracilaria: male structure development
Gracilaria: male structure development
Gracilaria: male structure development
Gracilariopsis: male structure development
all genera:
-tetrasporangial initials are surface cortical cells
-cruciate divisision of tetrasporangia
Gracilariaceae from the vicinity of Bocas del Toro
Gracilaria curtissiae
-thick thallus; thinner lateral
blade-like proliferations
Photo: A. Fricke & O. Camacho-Hadad
Photo: A. Fricke & O. Camacho-Hadad
Gracilaria intermedia
Gracilaria intermedia
Photo: A. Planas & C. Fernández)
Gracilaria cervicornis
Photo: M.C. Díaz Ruiz
Photo: R. Fikes
Gracilaria domingensis
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Photo: A. Fricke & O. Camacho-Hadad
Hydropuntia caudata
Gracilaria galetensis
Gracilaria hayi
Global Phylogeny of the Gracilariaceae
Bayesian Inferred Phylogeny
GTR+inv+gama
100,00 generations, 4 chains
Burn in = 20,000
Gurgel & Fredericq 2004