Figure 4

Effects of the overexpression and knockdown of AtYLMG1-1 on the morphology of the chloroplast nucleoids. (A) Morphology of the chloroplast nucleoids in the overexpresser and the knockdown lines. Expanding leaf or the basal part of expanding leaf cells of the wild type (WT), the AtYLMG1-1 knockdown line (AS), and the AtYLMG1-1 overexpresser (OX) were stained with DAPI. The white portion indicates DAPI fluorescence showing the localization of DNA. Nuclei (N) are also observed in some panels. Magnified images are also shown in the lower panels. Bars = 5 μm. All images were obtained with the same exposure time. (B) Morphology of the nucleoids in dividing chloroplasts. Young emerging leaves of the wild type were stained with SYBR GREEN I. The white portion indicates the SYBR GREEN I fluorescence showing the localization of DNA. Arrowheads indicate dividing chloroplasts. Other dividing chloroplasts are also shown in the right panels. Bars = 10 μm. (C) Comparison of the quantity of chloroplast DNA by DNA-blot analysis. Total genome DNA of the wild type (WT), the AtYLMG1-1 overexpresser (OX), and the AtYLMG1-1 knockdown line (AS) was extracted and then was digested with HindIII. Three micrograms of digested DNA were loaded in each lane. Chloroplast DNA (cp) was detected with a psbA probe and nuclear DNA (nu) was detected with a PsbO probe. Nuclear DNA was detected as the quantitative control. (D) Morphology of the chloroplast nucleoids in ftsZ2-1, arc5, and arc6 mutants. Mature leaves of the ftsZ2-1, arc5, and arc6 mutants were stained with DAPI. The white portion indicates DAPI fluorescence showing the localization of DNA. Bars = 5 μm. All images were obtained with the same exposure time.