Fig. 2.

Expression of Aqcoe3G231100 in F₂ hybrids and in A. coerulea ‘Origami.’ (A) Expression of Aqcoe3G231100 in petals (developmental stage $\sim$3 to 4) of F₂ individuals that are either homozygous A. ecalcarata (EE, n = 5), homozygous A. sibirica (SS, n = 5), or heterozygous (ES, n = 10) at the spur loss QTL. Each point represents normalized reads as assessed by RNAseq of a single F₂ individual, with the black bar indicating mean expression of all individuals for each genotype. (B) The number of Aqcoe3G231100 assignable reads transcribed from the A. ecalcarata allele (E reads) vs. the A. sibirica allele (S reads) for each of the 10 heterozygous F₂s in A. The dashed line represents the 1:1 ratio of E and S reads. (C) Relative expression of Aqcoe3G231100 in spur tissue of A. coerulea ‘Origami’ across the transition from mitotic growth (phase I, purple) to cell differentiation (phase II, gray) as assayed at a variety of developmental stages in three different plants. Developmental staging of petals is presented as the sample spur length relative to the spur length of a fully developed petal for each plant (i.e., proportion of full spur length). For various proportions, the range of spur lengths across the three plants assessed is also provided, in millimeters. (D–H) Spatial expression of Aqcoe3G231100 in petals at various developmental stages using in situ hybridization. (D) In a stage 7 floral meristem, Aqcoe3G231100 is expressed throughout early differentiating petal (p), stamen (st), staminode (sd), and carplel (car) primordia (floral stages based on ref. 27; see SI Appendix, Table S4 for stage comparison with RNAseq stage). (E) Aqcoe3G231100 is broadly expressed in the early petal of a stage 9 flower. (F) As development progresses, Aqcoe3G231100 expression contracts to the tip of the developing spur in an early stage 10 flower. (G) Late in stage 10, Aqcoe3G231100 is restricted to the adaxial layer of cells at the spur tip. (H) Magnification of the spur tip in G. (I) The sense probe showed no signal. (Scale bars: D, H, and I, 100 $\mathrm{\mu }$m; E, F, and G, 200 $\mathrm{\mu }$m.)