Fig. 2: Plastid exclusion in pollen development is compromised under chilling stress.
From: Control of plastid inheritance by environmental and genetic factors
a, Schematic diagram of pollen maturation in tobacco. Plastid exclusion is believed to occur in pollen mitosis I by a strongly asymmetric cell division, preventing entry of the vast majority of plastids into the GC in EBP. VC, vegetative cell; GCN, generative cell nucleus; VCN, vegetative cell nucleus. b, Map of the transgene-containing region in the ptDsRed plastid genome, harbouring the DsRed expression cassette and the spectinomycin resistance gene aadA. Expression elements (promoters, terminators and ribosome-binding sites, RBS) are indicated in blue. c, Confocal images of EBP in WTptDsRed plants. The CCW (grey) transiently formed after PMI is visualized by aniline blue staining (arrowheads). The open arrow points to a plastid (magenta) included in the GC in pollen developed at 10 °C. This experiment was repeated four times and representative images are shown. Scale bar, 10 μm. d, Time-lapse confocal images of in vitro germinating EPT expressing DsRed in plastids. The GCN (green) is visualized by SYTO11 staining. The GC membrane is indicated by a dotted line. Arrowheads and asterisks indicate plastids (magenta) located inside or outside the GC, respectively. This experiment was repeated ten times and representative images are shown. Scale bar, 5 μm. e, Proportion of pollen grains with plastids included in the GC. Each circle shows the proportion of plastid-containing GCs in an imaging session/replicate (Extended Data Table 3). Differences between experimental groups are represented by parameter values (β) expressed as log10 of the fold change, and were estimated using a binomial model (Model 2, nrep.total = 18 imaging sessions, 301 grains analysed; Extended Data Tables 1 and 2): βchilling represents the effect of the chilling treatment (P = 6.01 × 10−5); βexperiment represents differences between the EPT (P = 0.0288) and EBP experiments (Extended Data Table 2). Mean estimates and CI95 per experimental group are shown in black horizontal lines and coloured boxes, respectively. Parameters were tested using simultaneous two-tailed Wald z-tests. *P < 0.05; ***P < 0.001; α = 0.05.
