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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 function coordinately to inhibit hypocotyl elongation under red (R) light. (A) Representative seedlings of the WT Col-0, phyA-211, phyB-9 and phyA-211 phyB-9 mutants grown under R light (321 μmol·m−2·s−1) for 4 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) and PhyB shows a synergistic effect with phyA to promote seedling de-etiolation responses under high R light intensities. The means of three replicates (at least 30 seedlings per replicate) are shown ± SE.
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ijms-16-12199-f001: PhyA and phyB function coordinately to inhibit hypocotyl elongation under red (R) light. (A) Representative seedlings of the WT Col-0, phyA-211, phyB-9 and phyA-211 phyB-9 mutants grown under R light (321 μmol·m−2·s−1) for 4 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) and PhyB shows a synergistic effect with phyA to promote seedling de-etiolation responses under high R light intensities. The means of three replicates (at least 30 seedlings per replicate) are shown ± SE.

Mentions: Previous studies have shown that, under the dark condition, all Arabidopsis seedlings, including the Col-0 wild type (WT), the phyA-211 and phyB-9 single mutants, and the phyA-211 phyB-9 double mutant, exhibit skotomorphogenic characteristics, such as hypocotyl elongation, cotyledon folding, and apical hooks [1,3,31]. We found that, under the R light condition, the phyB-9 mutant had a significant elongated hypocotyl, while the phyA-211 mutant and the WT seedlings did not show altered hypocotyl (Figure 1A,B). Significantly, the phyA-211 phyB-9 double mutant seedlings had even longer hypocotyls than the phyB-9 single mutant did, consistent with the phenotype of the phyAphyB double mutant in the Landsberg erecta (Ler) ecotype background [21]. These results indicate that there might be a synergistic effect between phyA and phyB, which explains the additional hypocotyl elongation of the phyAphyB double mutant under the R light condition. To further investigate the relationship between phyA and phyB with respect to regulation of seedling de-etiolation upon R light exposure, we analyzed hypocotyl elongation among the Col-0, phyA-211, phyB-9, and phyA-211 phyB-9 lines under different intensities of R light (Figure 1C). When the R light density was below 26.1 μmol·m−2·s−1, no significant change of hypocotyl elongation was observed in the Col-0 WT seedlings, but the hypocotyl length gradually decreased with the increase of R light density thereafter, reaching the lowest peak at a high intensity of 642 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 function coordinately to inhibit hypocotyl elongation under red (R) light. (A) Representative seedlings of the WT Col-0, phyA-211, phyB-9 and phyA-211 phyB-9 mutants grown under R light (321 μmol·m−2·s−1) for 4 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) and PhyB shows a synergistic effect with phyA to promote seedling de-etiolation responses under high R light intensities. The means of three replicates (at least 30 seedlings per replicate) are shown ± SE.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4490439&req=5

ijms-16-12199-f001: PhyA and phyB function coordinately to inhibit hypocotyl elongation under red (R) light. (A) Representative seedlings of the WT Col-0, phyA-211, phyB-9 and phyA-211 phyB-9 mutants grown under R light (321 μmol·m−2·s−1) for 4 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) and PhyB shows a synergistic effect with phyA to promote seedling de-etiolation responses under high R light intensities. The means of three replicates (at least 30 seedlings per replicate) are shown ± SE.
Mentions: Previous studies have shown that, under the dark condition, all Arabidopsis seedlings, including the Col-0 wild type (WT), the phyA-211 and phyB-9 single mutants, and the phyA-211 phyB-9 double mutant, exhibit skotomorphogenic characteristics, such as hypocotyl elongation, cotyledon folding, and apical hooks [1,3,31]. We found that, under the R light condition, the phyB-9 mutant had a significant elongated hypocotyl, while the phyA-211 mutant and the WT seedlings did not show altered hypocotyl (Figure 1A,B). Significantly, the phyA-211 phyB-9 double mutant seedlings had even longer hypocotyls than the phyB-9 single mutant did, consistent with the phenotype of the phyAphyB double mutant in the Landsberg erecta (Ler) ecotype background [21]. These results indicate that there might be a synergistic effect between phyA and phyB, which explains the additional hypocotyl elongation of the phyAphyB double mutant under the R light condition. To further investigate the relationship between phyA and phyB with respect to regulation of seedling de-etiolation upon R light exposure, we analyzed hypocotyl elongation among the Col-0, phyA-211, phyB-9, and phyA-211 phyB-9 lines under different intensities of R light (Figure 1C). When the R light density was below 26.1 μmol·m−2·s−1, no significant change of hypocotyl elongation was observed in the Col-0 WT seedlings, but the hypocotyl length gradually decreased with the increase of R light density thereafter, reaching the lowest peak at a high intensity of 642 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.