Fig. 5: The synthetic deoxymugineic acid proline-2′-deoxymugineic acid enhances plant resilience to high-temperature stress.

a–d B. distachyon Bd21 plants grown in phenolic resin blocks containing 2.5 mg Fe L⁻¹ of non-chelated iron [Fe₂(SO₄)₃] under NC or HC for 4 weeks in the presence (+) or absence (−) of 30 µM proline-2′-deoxymugineic acid (PDMA). a Representative images of plants. b Simple ratio pigment index (SRPI) and photochemical reflectance index (PRI) values from the first fully expanded leaf. c Aboveground fresh weight. d Leaf Fe content. n = 9, 3, and 4 for (b–d), respectively. e, f Four-leaf-stage Bd21 seedlings were treated with 2.5 mg Fe L⁻¹ non-chelated iron in the presence or absence of 30 µM PDMA under NC or HC for 1 day. The first fully expanded leaves and root tissues were collected for RNA-seq analysis. e Fe deficiency–related gene expression. Each row represents one gene, and colors represent mean expression levels as log₂-normalized TPM values. Lower expression levels are shown in black, and higher expression levels are shown in yellow. f Photosystem and chlorophyll metabolism–related gene expression. Differentially expressed genes in response to high temperature are shown. Each row represents one gene, and colors represent mean expression level as z-score values. A positive z-score (orange) denotes values greater than the mean, and a negative z-score (blue) denotes values below the mean. g–j Effect of PDMA treatment on wheat ‘Fielder’ grown hydroponically with 2.5 mg Fe L⁻¹ of non-chelated iron in the presence (+) or absence (−) of 30 µM PDMA under HC for 4 weeks. g Representative images of plants. h TaIRO2.6 expression in the first fully expanded leaves. i SRPI and PRI values from the first fully expanded leaf. j Leaf Fe content. n = 3 for (h, j), n = 7 for (i). Data are means ± SEM. *P < 0.05 and **P < 0.001, from two-tailed Student’s t tests comparing values with and without PDMA; samples represent biologically independent replicates; exact P values for significant differences are shown on each graph. Source data are provided as a Source Data file.