Analysis of <i>Arabidopsis PSY</i> promoter activity in roots.

<p>Representative images from transgenic <i>PSY:GUS-GFP</i> (A, C, D, G–J) and control <i>35S:GUS-GFP</i> (B, E, F) seedlings are shown. (A) GUS staining of <i>PSY:GUS-GFP</i> seedlings. (B) GUS staining of <i>35S:GUS-GFP</i> seedlings. (C) Bright field image of the region boxed in blue in A. (D) GFP fluorescence of the root shown in C. (E) Bright field image of the region boxed in blue in B. (F) GFP fluorescence of the root shown in E. (G) GUS staining of the upper region of the root shown in C. (H) Cross-section of the root region shown in G. (I) Magnification of the region boxed in G. (J) Close up of the stele area in a GUS-stained and resin-embedded section. ep, epidermis; c, cortex; s, stele; en, endodermis; pe, pericycle; p, phloem; pc, phloem companion cells; x, xylem.</p

Effect of salt stress on ABA and carotenoid accumulation.

<p>(A) ABA quantification by LC-MS of root and shoot tissues from plants either treated (+) or not (−) with 200 mMNaCl for 5 h. The indicated samples were incubated with 20 µM norflurazon (NFZ) 48 h before and during the salt treatment. (B) Levels of β,βxanthophylls (β,β-x: neoxanthin and violaxanthin), β,β carotenes (β,β-c: β-carotene), and β,ε xanthophylls (β,ε-x: lutein) in root and shoot tissues separated from plants either treated (+) or not (−) with NaCl for 5 h. Data correspond to the mean and standard deviation of n = 3 independent samples. Asterisks mark statistically significant differences (p<0.01) relative to mock-treated controls.</p

Transcript levels of carotenoid and ABA biosynthetic genes in salt-treated seedlings.

<p>After transferring plants to plates containing 200 mMNaCl for the indicated times, total RNA was separately extracted from shoot and root tissues and used for qPCR analysis of <i>PSY</i> expression (A). Transcript levels were normalized using the <i>UBC</i> gene and represented relative to those before treatment (0 h). Similarly, root samples from plants either treated (+) or not (−) with NaCl for 2 h were used to estimate the levels of transcripts from the carotenoid biosynthetic genes <i>BCH2</i> and <i>ZEP</i> (B) or ABA biosynthetic genes <i>NCED3</i> and <i>AAO3</i> (C). Data correspond to the mean and standard deviation of n = 3 (A), n = 4 (B) and n = 2 (C) independent samples. Asterisks mark statistically significant differences (p<0.01) relative to mock-treated controls.</p