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Synergistic and Antagonistic Action of Phytochrome (Phy) A and PhyB during Seedling De-Etiolation in Arabidopsis thaliana.

Su L, Hou P, Song M, Zheng X, Guo L, Xiao Y, Yan L, Li W, Yang J - Int J Mol Sci (2015)

Bottom Line: In this work, we compared hypocotyl elongation of the phyA-211 phyB-9 double mutant with the wild type, the phyA-211 and phyB-9 single mutants under different intensities of far-red (FR), red (R), blue (B) and white (W) light.We confirmed that phyA and phyB synergistically promote seedling de-etiolation in B-, B plus R-, W- and high R-light conditions.Gene expression analyses of RBCS members and HY5 suggest that phyB and phyA act antagonistically on seedling development under FR light.

View Article: PubMed Central - PubMed

Affiliation: Maize Research Institute, Sichuan Agricultural University, Chengdu 611130, China. suliang_mp5@163.com.

ABSTRACT
It has been reported that Arabidopsis phytochrome (phy) A and phyB are crucial photoreceptors that display synergistic and antagonistic action during seedling de-etiolation in multiple light signaling pathways. However, the functional relationship between phyA and phyB is not fully understood under different kinds of light and in response to different intensities of such light. In this work, we compared hypocotyl elongation of the phyA-211 phyB-9 double mutant with the wild type, the phyA-211 and phyB-9 single mutants under different intensities of far-red (FR), red (R), blue (B) and white (W) light. We confirmed that phyA and phyB synergistically promote seedling de-etiolation in B-, B plus R-, W- and high R-light conditions. The correlation of endogenous ELONGATED HYPOCOTYL 5 (HY5) protein levels with the trend of hypocotyl elongation of all lines indicate that both phyA and phyB promote seedling photomorphogenesis in a synergistic manner in high-irradiance white light. Gene expression analyses of RBCS members and HY5 suggest that phyB and phyA act antagonistically on seedling development under FR light.

No MeSH data available.


PhyA and phyB synergistically promote de-etiolation under white (W) light. (A) Morphology of the WT Col-0, phyA-211, phyB-9 and phyA-211 phyB-9 grown under low W (100 μmol·m−2·s−1) light for four days. Bar = 2 mm; (B) Quantification of hypocotyl lengths of seedlings shown in A. The means of three replicates (at least 30 seedlings each replicate) are shown ± SE; (C) PhyB shows a synergistic effect with phyA to promote seedling de-etiolation responses under W light of different intensities. The means of three replicates (at least 30 seedlings per replicate) are shown ± SE; (D) Quantification of hypocotyl lengths under high W light (1200 μmol·m−2·s−1). Error bars indicate standard deviations. The means of three replicates (at least 30 seedlings each replicate) are shown ± SE; and (E) Immunoblot analyses of HY5 in seedlings shown in (D). An anti-HSP90-specific immunoblot, indicating approximately equal loading, is shown at the bottom.
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ijms-16-12199-f003: PhyA and phyB synergistically promote de-etiolation under white (W) light. (A) Morphology of the WT Col-0, phyA-211, phyB-9 and phyA-211 phyB-9 grown under low W (100 μmol·m−2·s−1) light for four days. Bar = 2 mm; (B) Quantification of hypocotyl lengths of seedlings shown in A. The means of three replicates (at least 30 seedlings each replicate) are shown ± SE; (C) PhyB shows a synergistic effect with phyA to promote seedling de-etiolation responses under W light of different intensities. The means of three replicates (at least 30 seedlings per replicate) are shown ± SE; (D) Quantification of hypocotyl lengths under high W light (1200 μmol·m−2·s−1). Error bars indicate standard deviations. The means of three replicates (at least 30 seedlings each replicate) are shown ± SE; and (E) Immunoblot analyses of HY5 in seedlings shown in (D). An anti-HSP90-specific immunoblot, indicating approximately equal loading, is shown at the bottom.

Mentions: Next, we tested whether phyA and phyB synergistically regulate Arabidopsis seedling photomorphogenesis upon W light exposure in a similar manner as they do in the R- and B-light conditions. Under 100 μmol·m−2·s−1 of W light, hypocotyl lengths of the phyA-211 or phyB-9 mutant seedlings were 1.4 or 2.9 folds longer than that of the WT Col-0, respectively (Figure 3A,B). All these four lines displayed slightly reduced hypocotyl under the weak W light (<8 μmol·m−2·s−1) and phyB-9 and WT lines showed a gradually reduced pattern of hypocotyl with increase of W light densities (Figure 3C). However, hypocotyl length of the phyB-9 mutant was notably longer than that of the WT Col-0 when W light intensities were between 19 and 260 μmol·m−2·s−1, whereas hypocotyl of phyA-211 mutant was significantly longer than that of the WT Col-0 when W light intensities were between 8 and 260 μmol·m−2·s−1. Most strikingly, hypocotyl length of the phyA-211 phyB-9 double mutant was always significantly longer than that of the phyA-211 or phyB-9 mutant. Taken together, we conclude that phyA and phyB synergistically promote seedling photomorphogenesis in response to W light, but not weak W light (<8 μmol·m−2·s−1).


Synergistic and Antagonistic Action of Phytochrome (Phy) A and PhyB during Seedling De-Etiolation in Arabidopsis thaliana.

Su L, Hou P, Song M, Zheng X, Guo L, Xiao Y, Yan L, Li W, Yang J - Int J Mol Sci (2015)

PhyA and phyB synergistically promote de-etiolation under white (W) light. (A) Morphology of the WT Col-0, phyA-211, phyB-9 and phyA-211 phyB-9 grown under low W (100 μmol·m−2·s−1) light for four days. Bar = 2 mm; (B) Quantification of hypocotyl lengths of seedlings shown in A. The means of three replicates (at least 30 seedlings each replicate) are shown ± SE; (C) PhyB shows a synergistic effect with phyA to promote seedling de-etiolation responses under W light of different intensities. The means of three replicates (at least 30 seedlings per replicate) are shown ± SE; (D) Quantification of hypocotyl lengths under high W light (1200 μmol·m−2·s−1). Error bars indicate standard deviations. The means of three replicates (at least 30 seedlings each replicate) are shown ± SE; and (E) Immunoblot analyses of HY5 in seedlings shown in (D). An anti-HSP90-specific immunoblot, indicating approximately equal loading, is shown at the bottom.
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ijms-16-12199-f003: PhyA and phyB synergistically promote de-etiolation under white (W) light. (A) Morphology of the WT Col-0, phyA-211, phyB-9 and phyA-211 phyB-9 grown under low W (100 μmol·m−2·s−1) light for four days. Bar = 2 mm; (B) Quantification of hypocotyl lengths of seedlings shown in A. The means of three replicates (at least 30 seedlings each replicate) are shown ± SE; (C) PhyB shows a synergistic effect with phyA to promote seedling de-etiolation responses under W light of different intensities. The means of three replicates (at least 30 seedlings per replicate) are shown ± SE; (D) Quantification of hypocotyl lengths under high W light (1200 μmol·m−2·s−1). Error bars indicate standard deviations. The means of three replicates (at least 30 seedlings each replicate) are shown ± SE; and (E) Immunoblot analyses of HY5 in seedlings shown in (D). An anti-HSP90-specific immunoblot, indicating approximately equal loading, is shown at the bottom.
Mentions: Next, we tested whether phyA and phyB synergistically regulate Arabidopsis seedling photomorphogenesis upon W light exposure in a similar manner as they do in the R- and B-light conditions. Under 100 μmol·m−2·s−1 of W light, hypocotyl lengths of the phyA-211 or phyB-9 mutant seedlings were 1.4 or 2.9 folds longer than that of the WT Col-0, respectively (Figure 3A,B). All these four lines displayed slightly reduced hypocotyl under the weak W light (<8 μmol·m−2·s−1) and phyB-9 and WT lines showed a gradually reduced pattern of hypocotyl with increase of W light densities (Figure 3C). However, hypocotyl length of the phyB-9 mutant was notably longer than that of the WT Col-0 when W light intensities were between 19 and 260 μmol·m−2·s−1, whereas hypocotyl of phyA-211 mutant was significantly longer than that of the WT Col-0 when W light intensities were between 8 and 260 μmol·m−2·s−1. Most strikingly, hypocotyl length of the phyA-211 phyB-9 double mutant was always significantly longer than that of the phyA-211 or phyB-9 mutant. Taken together, we conclude that phyA and phyB synergistically promote seedling photomorphogenesis in response to W light, but not weak W light (<8 μmol·m−2·s−1).

Bottom Line: In this work, we compared hypocotyl elongation of the phyA-211 phyB-9 double mutant with the wild type, the phyA-211 and phyB-9 single mutants under different intensities of far-red (FR), red (R), blue (B) and white (W) light.We confirmed that phyA and phyB synergistically promote seedling de-etiolation in B-, B plus R-, W- and high R-light conditions.Gene expression analyses of RBCS members and HY5 suggest that phyB and phyA act antagonistically on seedling development under FR light.

View Article: PubMed Central - PubMed

Affiliation: Maize Research Institute, Sichuan Agricultural University, Chengdu 611130, China. suliang_mp5@163.com.

ABSTRACT
It has been reported that Arabidopsis phytochrome (phy) A and phyB are crucial photoreceptors that display synergistic and antagonistic action during seedling de-etiolation in multiple light signaling pathways. However, the functional relationship between phyA and phyB is not fully understood under different kinds of light and in response to different intensities of such light. In this work, we compared hypocotyl elongation of the phyA-211 phyB-9 double mutant with the wild type, the phyA-211 and phyB-9 single mutants under different intensities of far-red (FR), red (R), blue (B) and white (W) light. We confirmed that phyA and phyB synergistically promote seedling de-etiolation in B-, B plus R-, W- and high R-light conditions. The correlation of endogenous ELONGATED HYPOCOTYL 5 (HY5) protein levels with the trend of hypocotyl elongation of all lines indicate that both phyA and phyB promote seedling photomorphogenesis in a synergistic manner in high-irradiance white light. Gene expression analyses of RBCS members and HY5 suggest that phyB and phyA act antagonistically on seedling development under FR light.

No MeSH data available.