Journal: Plant Physiology

Article Title: Auxin Metabolism and Function in the Multicellular Brown Alga Ectocarpus siliculosus ^{1 [W]}

doi: 10.1104/pp.109.149708

Figure Lengend Snippet: Morphology of the E. ssiliculosus sporophyte. The body of the E. siliculosus sporophyte is composed of two main parts: (1) the prostrate body attached to the substratum, corresponding to the vegetative phase; and (2) the upright body, corresponding to filaments growing vertically in seawater and ultimately differentiating sporangia. The prostrate body (PB) originates from germinating zygotes (or mitospores or unfertilized gametes; A), which produce a uniseriate filament composed of two cell types (B): E cells located at the apices and R cells at the center. About 10 d after germination (dag), the primary filament differentiates secondary prostrate axes (C). Upright filaments (UF) differentiate from the prostrate body, and these are composed of squared, large cells (D), ultimately developing sporangia (E).

Article Snippet: The number of branches was counted, and statistical analyses were performed using Student's t test. n = 32 for ASW and n = 23 for ASW + NAA 5 × 10 −6 m . Application of Auxin Compounds on E. siliculosus Tissues All the phytohormones were purchased from Duchefa Biochemie.

Techniques:

Journal: Plant Physiology

Article Title: Auxin Metabolism and Function in the Multicellular Brown Alga Ectocarpus siliculosus ^{1 [W]}

doi: 10.1104/pp.109.149708

Figure Lengend Snippet: Immunolocalization of IAA along the filaments of E. siliculosus. IAA was immunolocalized in very young sporophytic organisms (10 d old; blue-purple color; see “Materials and Methods”). A, Negative control corresponding to the omission of the primary antibody. B, α-Tubulin immunolocalization showing overall labeling. C, IAA immunolocalization showing the absence of IAA in the center of the filaments, corresponding mainly to R cells (stars). D, Detail of a filament apex after IAA immunolabeling, showing the absence of labeling in the central R cells. In these cells, the chloroplast is particularly visible as a golden brown area. Bars = 50 μm.

Article Snippet: The number of branches was counted, and statistical analyses were performed using Student's t test. n = 32 for ASW and n = 23 for ASW + NAA 5 × 10 −6 m . Application of Auxin Compounds on E. siliculosus Tissues All the phytohormones were purchased from Duchefa Biochemie.

Techniques: Negative Control, Labeling, Immunolabeling

Journal: Plant Physiology

Article Title: Auxin Metabolism and Function in the Multicellular Brown Alga Ectocarpus siliculosus ^{1 [W]}

doi: 10.1104/pp.109.149708

Figure Lengend Snippet: Indole compounds and putative enzymes involved in the synthesis of IAA in E. siliculosus. Substrates (black) and enzymes (blue) of the four biosynthetic pathways known or predicted in land plants (Woodward and Bartel, 2005; Nafisi et al., 2007; Sugawara et al., 2009) are presented. The indole product quantified in E. siliculosus sporophytes is framed in red. Putatively conserved enzymes inferred from genome sequence analysis of E. siliculosus are indicated by red dots. A yellow star indicates a BBH (see “Materials and Methods”).

Article Snippet: The number of branches was counted, and statistical analyses were performed using Student's t test. n = 32 for ASW and n = 23 for ASW + NAA 5 × 10 −6 m . Application of Auxin Compounds on E. siliculosus Tissues All the phytohormones were purchased from Duchefa Biochemie.

Techniques: Sequencing

Journal: Plant Physiology

Article Title: Auxin Metabolism and Function in the Multicellular Brown Alga Ectocarpus siliculosus ^{1 [W]}

doi: 10.1104/pp.109.149708

Figure Lengend Snippet: Sequence conservation between Arabidopsis and E. siliculosus Proteins of Arabidopsis involved in the different steps of auxin synthesis and function were used to query the whole proteome of E. siliculosus . For each function, only the best-matching pairs are reported (the complete analysis results are available as Supplemental Table S1). The Ath in Esi column shows the BLAST E values for the search of Arabidopsis proteins within the E. siliculosus proteome. A second BLAST search was performed for each best-matching protein of E. siliculosus in the complete proteome of Arabidopsis. The E value for this reverse BLAST query is reported in the column Esi in Ath in cases when the best hit is the initial Arabidopsis protein (the sequence pair is a bidirectional best hit). The EST column shows whether an EST for the E. siliculosus sequence is known. The Conserved Domains column gives the domains shared by the E. siliculosus and Arabidopsis similar proteins, found by InterProScan in the following databases: Gene3D, HAMAP, Pfam, PIRSF, PRINTS, ProSite, Panther, Superfamily, and TIGR, for which entries begin with G3DSA, MF, PF, PIRSF, PR, PS, PTHR, SSF, and TIGR, respectively.

Article Snippet: The number of branches was counted, and statistical analyses were performed using Student's t test. n = 32 for ASW and n = 23 for ASW + NAA 5 × 10 −6 m . Application of Auxin Compounds on E. siliculosus Tissues All the phytohormones were purchased from Duchefa Biochemie.

Techniques: Sequencing

Journal: Plant Physiology

Article Title: Auxin Metabolism and Function in the Multicellular Brown Alga Ectocarpus siliculosus ^{1 [W]}

doi: 10.1104/pp.109.149708

Figure Lengend Snippet: Effects of auxin compounds on the development of E. siliculosus sporophytes. Different auxin compounds were applied to E. siliculosus spores at germination time (A) or 20 d after germination (B). The effects on morphology were observed 2 weeks later. Application of 50 μm NAA on mitospores resulted in the differentiation of cells with an abnormal shape. Growth polarity was also affected. Application of IBA led to a similar effect, yet weaker, and PAA produced organisms with very long terminal cells and an altered branching pattern. When auxin compounds were added later during development (at 20 d after germination), the observed effects were different. While IAA increased the production of prostrate filaments, TIBA induced the differentiation of upright filaments (UF) earlier than in the control.

Article Snippet: The number of branches was counted, and statistical analyses were performed using Student's t test. n = 32 for ASW and n = 23 for ASW + NAA 5 × 10 −6 m . Application of Auxin Compounds on E. siliculosus Tissues All the phytohormones were purchased from Duchefa Biochemie.

Techniques: Produced, Control

Journal: Plant Physiology

Article Title: Auxin Metabolism and Function in the Multicellular Brown Alga Ectocarpus siliculosus ^{1 [W]}

doi: 10.1104/pp.109.149708

Figure Lengend Snippet: Model for the role of auxin in the development of the E. siliculosus sporophyte. Cells positioned at the apices of the filament acquire the E identity. A higher concentration of auxin is present in these cells, which prevents them from differentiating into R cells and/or inducing branching. As the filament grows, subapical E cells get localized farther from the apex and perceive lower auxin concentrations, which progressively induce their differentiation into R cells as well as branching. Later, auxin maintains its control on the progression of the life cycle by negatively controlling the emergence of the upright filament and thereby the shift to the reproductive phase. Auxin control would then depend on active transport, allowing the apices to maintain control on distant tissues.

Article Snippet: The number of branches was counted, and statistical analyses were performed using Student's t test. n = 32 for ASW and n = 23 for ASW + NAA 5 × 10 −6 m . Application of Auxin Compounds on E. siliculosus Tissues All the phytohormones were purchased from Duchefa Biochemie.

Techniques: Concentration Assay, Control