Figures and data
Phenotypic response of teosinte parviglumis and wild-type W22 maize grown under heavy metal stress.
(a) to (e), teosinte parviglumis; (f) to (j), W22 maize. (a) Teosinte parviglumis in absence of heavy metal stress at early flowering stage. (b) Teosinte parviglumis grown under heavy metal stress at early flowering stage. (c) Teosinte parviglumis in absence of heavy metal stress at late flowering stage. (d) Teosinte parviglumis grown under heavy metal stress at late flowering stage. (e) Teosinte parviglumis showing proliferation of female inflorescences arising from independent axillary meristems under heavy metal stress (detail of d). (f) W22 maize in absence of heavy metal stress at early flowering stage. (g) W22 maize grown under heavy metal stress at early flowering stage. (h) W22 maize in absence of heavy metal stress at late flowering stage. (i) W22 maize grown under heavy metal stress at late flowering stage. (j) W22 maize female inflorescences at late flowering stage (detail of i). Scale bars: 10 cm.
Estimation of phenotypic traits in teosinte parviglumis grown in absence and presence of heavy metal stress.
Genetic diversity of loci encompassing ZmHMA1, ZmHMA7, and ZmSKUs5.
The nucleotide variability index (π) was calculated for all HapMap3 accessions of teosinte parviglumis (blue line), maize (red line), and Tripsacum dactyloides (orange line), taking in consideration the coding sequence (arrow) and an upstream and downstream region of 15 Kb encompassing each gene. (a) Nucleotide variability in the ZmHMA1 locus. (b) Nucleotide variability in the ZmHMA7 locus. (c) Nucleotide variability in the ZmSKUs5 locus. (d) Nucleotide variability in the ZmGLB1 locus.
Structure and gene expression of ZmHMA1 and ZmHMA7 in teosinte parviglumis and W22 maize.
(a) Structural analysis of ZmHMA1, ZmHMA7, and ZMSKUs5. Blue triangles indicate the location of motifs predicted in the regulatory region of each gene. The insertion site of Mu line LANMu1029790 is indicated by a red triangle. (b) RT-PCR analysis of ZmHMA1 and ZMHMA7 expression throughout development of teosinte parviglumis and W22 maize in presence or absence of heavy metal stress; L=leaf; S=stem; PR=primary root; NR=nodal root; CR=crown root. V2: 15 days after transplant; V6: 30 days after transplant; R1: 50 days after transplant. Controls: (-) absence of DNA; (+) genomic DNA. (c) qPCR analysis of ZmHMA1 expression in 1-month old primary roots, in absence or presence of heavy metal stress. (d) qPCR analysis of ZmHMA7 expression in 1-month old primary roots, in absence or presence of heavy metal stress. * P<0.01; ** P<0.001.
Estimation of phenotypic traits in wild-type and zmhma1 maize grown in absence and presence of heavy metal stress.
Tb1 and ZmHMA1 expression in the shoot apical meristem of plantlets grown under heavy metal stress.
(a) qPCR analysis of Tb1 expression in 1-month old teosinte parviglumis plantlets grown in absence or presence of heavy metal stress. (b) qPCR analysis of ZmHMA1 expression in 1-month old teosinte parviglumis and W22 maize plantlets in absence or presence of heavy metal stress. * P<0.01.
Cumulative plot of QTL detected in a region of chromosome five that includes ZmSKUs5 and ZmHMA1 (modified from Lemmon and Doebley, 2024).
Molecular marker positions and gene location of ZmSKUs5 and ZmHMA1 are in centimorgans. Abbreviated QTLs are in the left margin. The 1.5-LOD support intervals for QTLs are in black horizontal bars and peak LOD scores in vertical lines. Hatched bars indicate interacting QTLs. Gray vertical shadings indicate the presence of a QTL cluster.
Comparison of chromosome 5 nucleotide variability between maize landraces and teosinte parviglumis.
Violin plots represent all neutral regions comprised chromosome 5 (blue), domestication genes previously reported in chromosome 5 (Hufford et al., 2012; green), the three candidate genes in this study (white), and their six neighboring genes (red). ANOVA-Tukey tests are represented by letters.
Expression of ZmHMA1 in wild-type and homozygous zmhma1 maize individuals.
A fragment of ZmHMA1 was the target of RT-PCR amplification in fourteen W22 wild-type and fourteen zmhma1 homozygous individuals. ZmCDK was used as a positive control in Wild-type individual number 1. A reaction without cDNA addition was used as a negative control. Corresponding primers are presented in Table S7.
Model illustrating the influence of heavy metal stress on the evolutionary transition of teosinte parviglumis to maize.
Additional estimation of phenotypic traits in teosinte parviglumis grown in absence or presence of heavy metal stress.
* P<0.05; ** P<0.01.
Additional estimation of phenotypic traits in wild-type and zmhma1 maize grown in absence or presence of heavy metal stress.
Full comparison of phenotypic values for wild-type W22, zmhma1, and teosinte parviglumis individuals grown under absence or presence of heavy metal stress.
Nucleotide variability across the ZmSKUS5, ZmHMA1 and ZmHMA7 locus; and their upstream and downstream neighboring genes in maize landraces, maize improved lines, and teosinte parviglumis accessions included in HapMap3.
Collection of primers used in this study.
Maize landrace accessions used in the genetic diversity analysis of chr5.
