Fig 1.
The morphology of samples and ultrastructural features of the anther cells during anther development in rapeseed.
(a) The main inflorescence of rapeseed. (b-d) The anther development stages were correlated with the length of the flower buds in rapeseed. Small buds with lengths less than 1 mm (b) contained anthers before and during the pollen mother cell stage; middle buds with lengths of 1–3 mm (c) contained anthers from meiosis to early uninucleate microspore stages; large buds with length larger than 3 mm (d) contained anthers from vacuolated microspore to mature pollen stages. (e-t) Ultrastructural features of the anthers at the pollen mother cell stage (e-h), the meiosis stage (i-l), the early uninucleate microspore stage (m-p), the vacuolated microspore stage (q-r), and the mature pollen stage (s-t). Ep, epidermis; En, endothecium; Ml, middle layer; Tp, tapetum; PMCs, pollen mother cells; P, plastid; Ex, extine; Mt, mitochondrion; Gi, Golgi body; ER, endoplasmic reticulum; Nu, nucleus; V, vacuole; Epl, elaioplast; Ts, tapetosome; In, intine; St, starch granules; Li, lipid bodies. Scale bar in a was 1 cm; scale bars in b-d were1 mm; scale bars in e, i were 10 nm; scale bars in k, o, q, s were 5 nm; scale bars in f, g, j, l, m were 2 nm, scale bars in h, n, r, t were 1 nm.
Fig 2.
Transcripts detected in leaves (Ls) and anthers at different development stages (a) and Venn diagrams showing the distribution of the differentially expressed transcripts (DETs) between leaves and anthers (b-c) or between different stage anthers (d-e) (b and d, up-regulated; c and e, down-regulated).
Table 1.
Distribution of DETs between leaves and developing anthers or between different developmental anthers.
Fig 3.
Dominant patterns of transcript expression and biological processes associated with anther development in rapeseed.
(a) Fifteen dominant patterns (DPs) of gene activity during rapeseed anther development. DP13, DP14 and DP15 were obtained by combining 4–7 sub-clusters with similar patterns. Detailed information is in S1 Fig. (b) Heatmap of enriched GO terms in DP1~DP12. GO terms were selected at P<0.001, with the darker blue color representing a more significant enrichment. The P-value was calculated according to a hypothesis test using a cumulative hypergeometric distribution and log10 transformed.
Table 2.
The distribution of lipid and carbohydrate metabolism related transcripts identified in each dominant pattern.
Fig 4.
The distribution of lipid and carbohydrate metabolism related genes in each dominant pattern (DP) and the expression profiles of the corresponding transcripts during rapeseed anther development.
(a-b) The percentage of unique AGIs with functions related to lipid (a) or carbohydrate (b) metabolism to total unique AGIs annotated in each DP was graphed, showing a relatively high percentage of lipid metabolism genes in DP1-DP5 and a high percentage of carbohydrate metabolism genes in DP6-DP12. (c-d) The expression profiles representing transcript levels of genes involved in lipid metabolism in DP1-DP5 (c) and carbohydrate metabolism (d) in DP6-DP12.
Fig 5.
Predicted AG transcriptional module during early anther development stages in rapeseed.
GO terms (blue circles) were enriched in DP5 (yellow octagon). The AG binding site motif (green diamond) is also enriched in DP5 and is predicted to be a target of three transcription factors (purple squares). Enrichment is at P<0.001 (hypergeometric distribution).