Fig. 2

Identification of the causal gene GUIDELESS. (a) Genome scan of the G^P/P NIL for regions that are enriched in homozygous SNPs compared with the M. lewisii reference genome. (b) Cross design to generate a fine-scale mapping population (BC₃S₁), and within this population, the three most informative recombinants reduced the candidate genomic interval to a smaller region (460 Kb) between markers MLCP6_200 and MLCP6_250. Nectar guide trichome length phenotypes (long vs. short) are shown on the right. (c) Front view of the whole corolla and enlarged view of the corolla throat of the G^P/P NIL, the guideless mutant, F1 between guideless and the wild-type M. lewisii (GL_F1), and F1 between guideless and the G^P/P NIL (GN_F1). Scale bars, 5 mm (top row) and 2 mm (bottom row). (d) Quantification of nectar guide trichome lengths (n = 20 for each genotype). Error bars are 1 SD. Asterisks indicate differences from the wild-type M. lewisii (** p < 0.01, student’s t test). (e) Expression analysis of GUIDELESS by RT-qPCR