Fig. 3: Allelic variants of YUC8 cause variation in LR length at low N.
From: Local auxin biosynthesis acts downstream of brassinosteroids to trigger root foraging for nitrogen
a Association of 17 polymorphic sites (MAF > 0.05) in the coding region of single-exon gene YUC8 in 139 re-sequenced accessions with average LR length under high N (HN, 11.4 mM N; red) or low N (LN, 0.55 mM N; cyan). The x-axis shows the nucleotide position of each variant. The y-axis shows the −log10 (P-value) for the association test using a generalized linear model (GLM), with a significance level at α = 0.05 indicated with a dashed red line. The six polymorphisms selected for further analysis were projected onto a schematic representation of a YUC8 gene structure represented by a light blue arrow. b Average LR length of natural accessions representing two major YUC8 haplotypes (n = 126 and 10 accessions for haplotype A and haplotype B, respectively). Dots represent means ± SEM and P values relate to differences between two haplogroups under respective N conditions according to Welch’s t-test. c Schematic of YUC8 constructs to complement the yucQ mutant. d–g Root phenotype of transgenic allelic complementation lines at low N. Appearance of plants (d), PR length (e), average LR length (f), and total root length (g) at LN of wild-type (Col-0), yucQ and independent transgenic plants expressing sequences coding for either YUC8-haplotype A or YUC8-haplotype B under control of the YUC8Col-0 promoter. Six independent T2 lines for each construct were assessed. Two representative lines are shown for each construct. Root system architecture was assessed after 9 days. Horizontal lines show medians; box limits indicate the 25th and 75th percentiles; whiskers extend to 1.5 times the interquartile range from the 25th and 75th percentiles. Numbers below each box indicate the number of plants assessed for each genotype under the respective N condition. Different letters in (e–g) indicate significant differences at P < 0.01 according to one-way ANOVA and post hoc Tukey test. P values relate to differences between two complementing groups according to Welch’s t-test. Scale bar, 1 cm.
