Figure 5.

CRF2 Overexpression or Cytokinin Treatment Increases the PDV2 Level and Increases the Number and Decreases the Size of Chloroplasts.

(A) Chloroplasts of wild-type and transgenic plants overexpressing CRF2 (35S-CRF2) in single leaf mesophyll cells. Tips of the first true leaves were cut from ∼3-week-old plants grown on agar plates. Bar = 20 μm.

(B) Effect of cytokinin treatment on the size and number of chloroplasts. Chloroplasts in single mesophyll cells of the cotyledon are shown. Wild-type seeds were germinated and grown for 10 d on agar plates with (+BA) or without (−BA) 5 μM BA. Bar = 20 μm.

(C) RT-PCR analyses showing the CRF2 transcript was increased in 35S-CRF2 transgenic plants. Total RNA extracted from rosettes was used for RT-PCR. UBQ1 was used as the internal control. The number of PCR cycles was 28 for CRF2 and 26 for UBQ1. The signals were estimated by ethidium bromide staining. Two biological replicates showed the same result.

(D) Immunoblot analyses comparing the levels of the chloroplast division proteins between the wild type and CRF2 overexpresser. The same amount of total protein extracted from ∼3-week-old russets was loaded in each lane. Rubisco large subunit stained by Ponceau S is shown as the loading control. Three biological replicates showed the same result.

(E) Immunoblot analyses comparing the levels of the chloroplast division proteins between wild-type seedlings germinated on medium with (+BA) or without (−BA) BA. The same amount of total protein extracted from 10-d-old seedlings was loaded in each lane. PDV2, FtsZ2-1, GFP-DRP5B, and ARC6-GFP were detected as in Figure 2B. Three biological replicates showed the same result.

[See online article for color version of this figure.]