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Maize EMBRYO SAC family peptides interact differentially with pollen tubes and fungal cells.

Woriedh M, Merkl R, Dresselhaus T - J. Exp. Bot. (2015)

Bottom Line: Furthermore, peptide fragments were found to bind differently to fungal cells.Mapping of peptide interaction sites identified amino acids differing in pollen tube burst and fungal response reactions.In summary, these findings indicate that residues targeting pollen tube burst in maize are specific to the ES family, while residues targeting fungal growth are conserved within defensins and defensin-like peptides.

View Article: PubMed Central - PubMed

Affiliation: Cell Biology and Plant Biochemistry, Biochemie-Zentrum Regensburg, University of Regensburg, 93053 Regensburg, Germany.

No MeSH data available.


Related in: MedlinePlus

ES-d interacts with the surface of maize pollen tubes. (A, B) Maize pollen grains were germinated for 15min in PGM before addition of ES-d at 500nM. (A) A few seconds after ES-d application, pollen tube tips start swelling and immediately burst explosively at the apex (B). Arrowheads indicate swelling and burst. (C-J) Maize pollen grains were germinated for 15min in PGM before addition of TAMRA-ES-d at 50nM. Two minutes after TAMRA-ES-d application, labelled ES-d appears at the apex of germinating pollen tube (C, D) and throughout the whole pollen tube surface. Tubes burst explosively at the apex as indicated by arrowheads (E-F). Example showing TAMRA-ES-d bound along the pollen tube surface (G, H). Accumulation of TAMRA-ES-d (arrowheads) occurred at pollen tube tip preceding burst (I, J). (K, L) Binding of Rhodamin-ES4 at the pollen tube surface, and (M, N) bursting at the tip. (C, E, G I, K, M) show merge of bright field and fluorescence micrographs, while (D, F, H, J, L, N) show fluorescence micrographs. Scale bars are 50 µm in (K, L), 20 µm in (A-F, M, N) and 5 µm in (G-J).
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Figure 3: ES-d interacts with the surface of maize pollen tubes. (A, B) Maize pollen grains were germinated for 15min in PGM before addition of ES-d at 500nM. (A) A few seconds after ES-d application, pollen tube tips start swelling and immediately burst explosively at the apex (B). Arrowheads indicate swelling and burst. (C-J) Maize pollen grains were germinated for 15min in PGM before addition of TAMRA-ES-d at 50nM. Two minutes after TAMRA-ES-d application, labelled ES-d appears at the apex of germinating pollen tube (C, D) and throughout the whole pollen tube surface. Tubes burst explosively at the apex as indicated by arrowheads (E-F). Example showing TAMRA-ES-d bound along the pollen tube surface (G, H). Accumulation of TAMRA-ES-d (arrowheads) occurred at pollen tube tip preceding burst (I, J). (K, L) Binding of Rhodamin-ES4 at the pollen tube surface, and (M, N) bursting at the tip. (C, E, G I, K, M) show merge of bright field and fluorescence micrographs, while (D, F, H, J, L, N) show fluorescence micrographs. Scale bars are 50 µm in (K, L), 20 µm in (A-F, M, N) and 5 µm in (G-J).

Mentions: It is difficult to investigate the binding of ES peptides at maize pollen tubes because application of ES-d (similar to ES1 and ES4) causes swelling of tube tips and growth arrest prior to explosive burst at the tube apex within a few seconds (Fig. 3A, B). To visualize the interaction and binding sites of ES-d on maize pollen tubes and to prolong swelling time to 2min prior to burst, a low concentration of 50nM of ES-d labelled with the fluorescent dye TAMRA was applied to germinated pollen tubes. The tubes showed fluorescence on the entire surface, which increased at the tips (Fig. 3C-J), causing swelling prior to explosive burst at the apex (Fig. 3E, F). Fluorescence was not detected on pollen grains. The same binding behaviour was observed after application of ES4 labelled with the fluorescent dye rhodamine. Here, burst occurred at the same concentration after 5min, indicating that longer peptides need more time to interact with the pollen tube surface (Fig. 3K-N). The same binding assay was repeated using ES-a and ES-c at the same concentration labelled with the fluorescent dyes TAMRA (ES-a) or Dabcyl (ES-c). For both assays, fluorescence was not observed in pollen grains and tubes (Supplementary Fig. S1).


Maize EMBRYO SAC family peptides interact differentially with pollen tubes and fungal cells.

Woriedh M, Merkl R, Dresselhaus T - J. Exp. Bot. (2015)

ES-d interacts with the surface of maize pollen tubes. (A, B) Maize pollen grains were germinated for 15min in PGM before addition of ES-d at 500nM. (A) A few seconds after ES-d application, pollen tube tips start swelling and immediately burst explosively at the apex (B). Arrowheads indicate swelling and burst. (C-J) Maize pollen grains were germinated for 15min in PGM before addition of TAMRA-ES-d at 50nM. Two minutes after TAMRA-ES-d application, labelled ES-d appears at the apex of germinating pollen tube (C, D) and throughout the whole pollen tube surface. Tubes burst explosively at the apex as indicated by arrowheads (E-F). Example showing TAMRA-ES-d bound along the pollen tube surface (G, H). Accumulation of TAMRA-ES-d (arrowheads) occurred at pollen tube tip preceding burst (I, J). (K, L) Binding of Rhodamin-ES4 at the pollen tube surface, and (M, N) bursting at the tip. (C, E, G I, K, M) show merge of bright field and fluorescence micrographs, while (D, F, H, J, L, N) show fluorescence micrographs. Scale bars are 50 µm in (K, L), 20 µm in (A-F, M, N) and 5 µm in (G-J).
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Related In: Results  -  Collection

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Figure 3: ES-d interacts with the surface of maize pollen tubes. (A, B) Maize pollen grains were germinated for 15min in PGM before addition of ES-d at 500nM. (A) A few seconds after ES-d application, pollen tube tips start swelling and immediately burst explosively at the apex (B). Arrowheads indicate swelling and burst. (C-J) Maize pollen grains were germinated for 15min in PGM before addition of TAMRA-ES-d at 50nM. Two minutes after TAMRA-ES-d application, labelled ES-d appears at the apex of germinating pollen tube (C, D) and throughout the whole pollen tube surface. Tubes burst explosively at the apex as indicated by arrowheads (E-F). Example showing TAMRA-ES-d bound along the pollen tube surface (G, H). Accumulation of TAMRA-ES-d (arrowheads) occurred at pollen tube tip preceding burst (I, J). (K, L) Binding of Rhodamin-ES4 at the pollen tube surface, and (M, N) bursting at the tip. (C, E, G I, K, M) show merge of bright field and fluorescence micrographs, while (D, F, H, J, L, N) show fluorescence micrographs. Scale bars are 50 µm in (K, L), 20 µm in (A-F, M, N) and 5 µm in (G-J).
Mentions: It is difficult to investigate the binding of ES peptides at maize pollen tubes because application of ES-d (similar to ES1 and ES4) causes swelling of tube tips and growth arrest prior to explosive burst at the tube apex within a few seconds (Fig. 3A, B). To visualize the interaction and binding sites of ES-d on maize pollen tubes and to prolong swelling time to 2min prior to burst, a low concentration of 50nM of ES-d labelled with the fluorescent dye TAMRA was applied to germinated pollen tubes. The tubes showed fluorescence on the entire surface, which increased at the tips (Fig. 3C-J), causing swelling prior to explosive burst at the apex (Fig. 3E, F). Fluorescence was not detected on pollen grains. The same binding behaviour was observed after application of ES4 labelled with the fluorescent dye rhodamine. Here, burst occurred at the same concentration after 5min, indicating that longer peptides need more time to interact with the pollen tube surface (Fig. 3K-N). The same binding assay was repeated using ES-a and ES-c at the same concentration labelled with the fluorescent dyes TAMRA (ES-a) or Dabcyl (ES-c). For both assays, fluorescence was not observed in pollen grains and tubes (Supplementary Fig. S1).

Bottom Line: Furthermore, peptide fragments were found to bind differently to fungal cells.Mapping of peptide interaction sites identified amino acids differing in pollen tube burst and fungal response reactions.In summary, these findings indicate that residues targeting pollen tube burst in maize are specific to the ES family, while residues targeting fungal growth are conserved within defensins and defensin-like peptides.

View Article: PubMed Central - PubMed

Affiliation: Cell Biology and Plant Biochemistry, Biochemie-Zentrum Regensburg, University of Regensburg, 93053 Regensburg, Germany.

No MeSH data available.


Related in: MedlinePlus