Fig 1.
Schematic representation of the Cry1Ab transgene cassette, used in the making of MON810.
Fig 2.
Heights (cm), measured in plants grown in the field in control conditions (100% field capacity) and in stressed conditions (25% and 0% field capacity).
Table 1.
Primer and probe sequences utilised for the expression analysis of the target genes by qRT-PCR.
Table 2.
Percentage variation in the drought stress treatment (irrigation 0% of field capacity) with respect to the control (irrigation 0% of field capacity) for selected photosynthesis (A = net photosynthesis; gs = stomatal conductance to water vapour; E = leaf transpiration; Ci/Ca = ratio between stomatal and ambient CO2 concentration; WUE = Water Use Efficiency), and fluorescence parameters (ΦPSII = effective quantum efficiency of PSII; qP = photochemical quenching; qNP = non photochemical quenching; ETR = electron transport rate; Fv/Fm = maximum quantum yield of PSII), measured on Tietar and DKC6575 at T2 (after 20 d without irrigation) in the field experiment.
Table 3.
Two-Way ANOVA on selected photosynthesis (A = net photosynthesis; gs = stomatal conductance to water vapour; E = leaf transpiration; Ci/Ca = ratio between stomatal and ambient CO2 concentration; WUE = Water Use Efficiency), and fluorescence parameters (ΦPSII = effective quantum efficiency of PSII; qP = photochemical quenching; qNP = non photochemical quenching; ETR = electron transport rate; Fv/Fm = maximum quantum yield of PSII), measured on Tietar and DKC6575 at T2 (after 20 d without irrigation) in the field experiment.
Fig 3.
Percentage variation of the drought stress treatment (irrigation 0% of field capacity) in respect to the control (irrigation 100% of field capacity) for gas exchanges parameters measured in the growth chamber experiment.
The straight line at the “0” level represents the control, and histograms represent the relative variations of drought stressed plants.
Table 4.
Two-Way ANOVA on gas exchange and chlorophyll fluorescence parameters, for each measurement date in the growth chamber experiment.
0I, 0II = before the beginning of the drought treatment; SI, SII, SIII = corresponding to 4, 5 and 6 d from the last irrigation of the drought stressed sets, respectively; RI, RII = corresponding to 2 and 4 d after re-irrigation of the drought stressed sets.
Fig 4.
Percentage variation of the drought stress treatment (irrigation 0% of field capacity) with respect to the control (irrigation 100% of field capacity) for selected chlorophyll fluorescence parameters measured in the growth chamber experiment.
The straight line at the “0” level represents the control, and histograms represent the relative variations of drought stressed plants.
Table 5.
Dry biomass (g) of leaves, stems, and roots, of control and drought stressed plants at the end of the drought treatment in the growth chamber experiment.
Table 6.
Two-Way ANOVA on dry biomass (g) of leaves, stems, and roots, of non-stressed and drought stressed plants at the end of the drought treatment in the growth chamber experiment.
Fig 5.
Time course of Zmdhn1 and CryIAb transcription evaluated by qRT-PCR in samples from the Field experiment.
Samples of leaves were collected from plants in the Field experiment at the vegetative six-leaves stage (V6) (T0 stage), at the vegetative eight-leaves stage (V8) (T1 stage) and at silking (R1) (T2 stage), all at the same hour of day. 0% plants not irrigated from V6 stage to harvest; 100% plants fully irrigated (control). Relative quantification of gene expression is based on the 2-ΔΔCt method using Zmabp3 as reference gene. Samples are a pool of four plants that were examined in triplicate. Each value is the mean +/- SD. ** indicate a significant difference at p<0.01 evaluated by ANOVA.
Fig 6.
Time course of Zmdhn1 and CryIAb transcription evaluated by qRT-PCR in samples of the Growth chamber experiment.
Samples of leaves were collected from plants at full irrigation of all sets (0I, 0II) during the drought treatment (SI, SII, corresponding to 4, and 5 d from the last irrigation of the “S” sets), and after the re-irrigation of the S sets (RI, RII corresponding to 2 and 4 d after re-irrigation). Relative quantification of gene expression is based on the 2-ΔΔCt method using Zmabp3 as reference gene and samples 0I and 0II as control. Samples are a pool of two plants that were examined in triplicate. Each value is the mean +/- SD. ** indicate a significant difference at p<0.01 evaluated by ANOVA.
Fig 7.
Venn diagrams representing the number of genes differentially expressed based on microarray analysis.
Plants grown in the Field experiment were sampled at the developmental stage T2 in the drought stress condition and at T1 and T2 in the control condition. Genes considered are those showing a fold change (FC) ≥±2.
Fig 8.
Functional annotation chart of the transcripts up-regulated in Tietar (A) and in DKC6575 (B) in response to drought stress.
Fig 9.
Hierarchical clustering of transcriptional responses of different classes of genes in the two maize genotypes: a) Heat Shock Proteins, Late Embryogenesis Abundant proteins and dehydrins; b) transcription factors.
Sample numbers are indicated on the top: 1) DKC6575 at T2 drought stress; 2) DKC6575 at T2 control condition; 3) Tietar at T2 drought stress; 4) Tietar at T2 control condition. A heat map was generated by Java TreeView 1.60 software. Each colored block represents the expression of one gene (labeled on the right) in the indicated sample. Expression signals are converted into color (red, high signal; green, low signal). A ≥2 fold change is shown in red, a fold change ≤0.5 in green and no change in black. Color intensities are proportional to the variation of expression.