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. 2017 May 11;8:15236. doi: 10.1038/ncomms15236

Figure 3. PPKs function collectively in promoting light-induced phyB degradation.

Figure 3

(a) Light-induced degradation of phyB is reduced in the ppk123 mutant. Seedlings were grown either in the dark (Dk) or continuous red right (Rc) for 4 days before protein extraction and immunoblot analysis using either anti-phyB antibody, or anti-tubulin as a loading control (left panel). Right panel shows quantification of the phyB levels relative to the tubulin protein levels from three biological replicates, expressed as a percentage of the dark-seedling levels for each genotype. Error bars represent s.e. **P<0.01 (Student's t-test). (b) A phyB null mutation suppresses the hypersensitive, short-hypocotyl phenotype of the ppk123 mutant in the light (phyB:ppk123). Average hypocotyl lengths of 4-day Dk- or Rc-grown seedlings are shown at right. Error bars represent s.e. from three biological replicates. ***P<0.001 (Student's t-test). (c) The light-hypersensitive phenotype of the ppk123 triple mutant includes enhanced cotyledon expansion compared to WT. Error bars represent s.e. from three biological replicates. ***P<0.001 (Student's t-test). (d) PPK1, PPK2, PPK3 and PPK4 are collectively necessary for normal PIF3 promoted phyB degradation in the light. Light-induced degradation of phyB is reduced in the ppk123, ppk134 and ppk124 triple-mutant backgrounds, and this reduced phyB degradation in the ppk124 triple-mutant can be rescued by transgenic expression of PPK1:CFP (PPK1:CFP/ppk124). Seedlings of the indicated genotypes were grown for 4 days in the dark or continuous red light (Rc) before protein extraction and western blot analysis using an anti-phyB antibody, or anti-tubulin as a loading control. (e) PPKs are collectively necessary for normal hypocotyl responsiveness to light. Seedlings of the indicated genotypes were grown as in d. Scale bars, 5 mm. (f) Light-induced degradation of phyB is reduced in the amiR-PPK1234 line. Seedling growth and western blot were done as in d. (g) The amiR-PPK1234 line is hypersensitive to red light. Seedlings were grown for 4 days in red light.