Figure 6.

Protochlorophylide, Galactolipid, and β-Carotene Contents of miR-mdh-1 Seedlings.

(A) Protochlorophyllide levels in 5-d-old wild-type (Col) and miR-mdh-1 etiolated seedlings, measured by fluorescence after excitation at 440 nm. Values are the means ± se of three biological replicates, each measured with four technical replicates. Each biological replicate is a pool of 100 to 200 individual seedlings.

(B) Immunoblot detection of PORA in total protein extracts from 6-d-old etiolated wild-type and miR-mdh-1 seedlings (upper panel). Immunoblots for actin was performed as a loading control (lower panel). Gels were loaded on an equal fresh weight basis. Three biological replicates are shown. Each biological replicate is a pool of 50 to 100 individual seedlings.

(C) to (F) Lipids and carotenoids were extracted from 6-d-old wild-type and miR-mdh-1 seedlings, either etiolated (E) or light grown (l; grown under a 12-h-light/12-h-dark regime). Levels of DAG (C), MGDG 18:3/16:3 (D) DGDG 18:3/18:3 (E), and β-carotene (F) are shown. For the lipids, only the most common species (in terms of fatty acid chain composition) is shown; similar trends were seen in other detected species (Supplemental Table 1). All lipids and carotenoids were quantified relative to an internal standard, and values were corrected for differences in fresh weight (see Methods for details). Values are the mean ± se from four biological replicates. Each biological replicate is a pool of 50 to 100 individual seedlings. Significant differences (P < 0.05) within the respective light-grown and etiolated samples of miR-mdh-1 and the wild type, determined using a two-tailed t test, are indicated with an asterisk.