Fig 1.
Stomatal conductance (gs) and chlorophyll concentrations of the green bracts and white bracts of S. chinensis.
Stomatal conductance (gs) and chlorophyll concentrations of white and green bracts from different plant leaves were measured, respectively. Each sample was done in triplicate, and the error bars represent the standard deviation of the three independent experiments.
Fig 2.
Scanning electron microscope micrographs of green bracts and white bracts.
A) Adaxial surface of green bract. B, C) Abaxial surface of green bract. D, E, F, I) Abaxial surface of white bracts. G, H) Adaxial surface of white bract. Scale bars for A, C, D and G equal 100 μm, and scale bars for B, E, F, H and I equal 10 μm.
Fig 3.
Transmission electron micrographs of chloroplasts and cell walls of green bracts and white bracts of S. chinensis.
A, B) Chloroplast in green bract; D, E) Chloroplast in white bract; C) Cell wall in green bract; F) Cell wall in white bract; A and B, Scale bars represent 1 um; C, D, E and F, Scale bars represent 2 μm.
Table 1.
Summary of illumina paired-end sequencing and assembly for S. chinensis.
Fig 4.
Functional annotation of assembled unigenes based on Gene Ontology (GO) categorization.
The results are summarized in three main categories: biological process, cellular component and molecular function.
Fig 5.
Proportion of up-regulated (white) and down-regulated (grey) differentially expressed genes at different stages of bract development. 1) Green tissue in bracts undergoing green-to-white transition; 2) White tissue in bracts undergoing green-to-white transition; 3) Fully white bracts; 4) White tissue in bracts during white-to-green reversion; 5) Pale green tissue during white-to-green reversion; 6) Fully pale green bracts.
Fig 6.
Validation of microarray results by qRT-PCR for selected genes.
ScAP1-A and ScAP1-B MADS-box genes are F1254 and AY057378; ScAP3-A and ScAP3-B MADS-box genes are EH662329 and EG530709; ScPI-A and ScPI-B MADS-box genes are EG530711 and D658; the transcription factors are F431, F480, F583 and F1387. α-TUBULIN (JK704891) was used as an internal control for normalization of the template cDNA. Each sample was done in triplicate, and the error bars represent the standard deviation of the three independent experiments. In each graph, the white bars represent the relative expression found in the microarray experiments, and the black bars represent the relative expression determined by normalized qRT-PCR. The number 1 to 6 correspond in the X axis represent the half green and half white during the transition of green to white bracts, the fully white, as well as the stages following floral senescence the half green and half white during the transition of white to green bracts, and Fully pale green bracts when bracts are reverting back to green coloration.
Fig 7.
Comparison of the C-terminal region of amino acid sequences for MADS-box B class genes.
ScAP1-A and ScAP1-B have a conserved MPPWML motif in the C-terminal region. ScAP3-A and ScAP3-B shared a PI-derived motif and a characteristic ancestral paleoAP3 motif. ScPI-A and ScPI-B protein has the highly conserved sequence PI-motif in the C-terminal region.
Fig 8.
Bootstrap consensus tree of Minimum Evolution method analysis of the putative A-class and B-class MADS-box transcription factors, using 1000 bootstrap iterations.
Black triangles represent the A-class and B-class MADS-box genes from S. chinensis in this study and others from GenBank that were included in the analysis.
Table 2.
Pairwise dN/dS analyses on five MADS-box genes with AP3 and nine MADS-box genes with PI.
Fig 9.
Yeast two-hybrid interactions of five MADS-box B class proteins of S. chinensis.
GAL4-based yeast two-hybrid vectors pGADT7 vector (AD) and pGBKT7 vector (BK) and co-transformed into the AH109 yeast strain. Yeast growth on selection plates SD/-Trp-Leu-His-Ade/X-α-GAL solid medium.
Fig 10.
Morphological diversity of the green bracts and white bracts of Saururus chinensis.
A) Bracts are initially green. B) Top three bracts are white. C) Occasionally, upper-most bracts are reduced in size and colored white on both adaxial and abaxial surfaces. D) A bee feeding from flowers of S. chinensis.