Fig. 1

Meta-expression analysis and genome-wide identification of OsRopGEF and validation of meta-expression patterns of pollen-specific OsRopGEFs using qPCR. a Heatmap expression and phylogenetic analysis of 11 OsRopGEF genes revealed four genes are specifically expressed in MP. 22 microarray data for indica rice including five stages for anthers and three for pollen and 42 microarray data for japonica rice including eight stages for anthers and five for pollen were used. ACF, archesporial cell-forming stage; BG, bi-cellular gametophyte stage; Fl, flowering stage; GP, germinated pollen; Me, meiotic stage; Me1, meiotic leptotene stage; Me2, meiotic zygotene-pachytene stage; Me3, meiotic diplotene-tetrad stage; MP, mature pollen stage; PMe, pre-meiosis; TG, tricellular pollen stage; UG, uni-cellular gametophyte stage. Yellow color in heatmap indicates high level of expression; dark blue, low expression. Numeric values indicate an average of the normalized log2 intensity of microarray data. b Expression of pollen-preferred OsRopGEF genes was analyzed by qPCR in various tissues of rice; the anther of tetrad, microspore, vacuolated pollen stage and mature pollen grains were used. Rice ubiquitin 5 (OsUbi5, LOC_Os01g22490) was used as an internal control. Y-axis, expression level relative to OsUbi5; X-axis, samples used for analyses. Error bars represent the standard errors of three biological replicates. Significant differences are indicated by asterisks, *, p-value < 0.01. Data were analyzed by employing one-way ANOVA with repeated measures, using Tukey’s pairwise comparison test