Fig. 2.

agb1 mutation alters adaptive responses to iron deprivation, zinc deprivation, and zinc excess conditions. (a) qRT-PCR analyses of marker genes. Roughly 100 Col-0 and agb1-2 5-day-old seedlings were pooled for RNA extraction from iron, zinc, and copper deficiency, and zinc excess conditions. The heat map shows the mean of log₂-transformed relative expression levels from three biological replicates. The black filled squares indicate that marker genes exhibited differential expression under certain stress conditions. The blue box highlights zinc markers that are misregulated significantly in agb1-2. The green box shows iron-responsive genes up-regulated in agb1-2 under the control condition. Asterisks indicate significant differences from Col-0 with the control treatment. *P<0.05 and **P<0.01. (b) Metal contents in WT and agb1-2 plants grown in control, iron and zinc deficiency, and zinc excess conditions. The metal contents (mg or μg g DW^–1 of tissue) were determined by ICP-OES from 18-day-old seedlings. Data shown are the mean of two different biological replicates with the SD. Student’s t-test was used to determine significant differences. *P<0.05. (c) Representative photos of phenotypes shown in Col-0, gpa1-3, and agb1-2 plants. Photos were taken after 12 d of treatment. Red arrowheads indicate plants that exhibit growth arrest or chlorotic leaves. (d) Quantitative data analyzed from phenotypic assay. The heatmap indicated a decrease (blue) or an increase (red) with respect to the mean value of three genotypes (Col-0, gpa1-3, and agb1-2) under control, iron and zinc deficiency, and zinc excess conditions. Each row represented individual physiological traits ordered by the hierarchical clustering algorithm. Chl denotes chlorophyll. Original physiological data are available in Supplementary Table S5. Asterisks in (b) and (d) represent significant differences from the WT group for each stress treatment.