Fig. 7. Nitrate signalling mediated by Nlp1 and Nlp4 acts upstream of cytokinin biosynthesis to restrict symbiotic signalling.

A Images of nodules developed in the absence and presence of 5 mM KNO₃ at 14 dpi with M. loti on the indicated host genotypes. Scale bar = 1 mm. B–D Development of total (B), mature (C), and proportion of mature nodules (D) in the absence and presence of 5 mM KNO₃ at 14 dpi with M. loti. E Nitrogenase activity assessed by ARA at 21 dpi with M. loti in the absence and presence of 5 mM KNO₃. F Formation of spontaneous nodules in response to cytokinin (BA). Box plots show Min, Q1, Median, Q3, Max and outlier values in nodulation assays (B–D, F). Bars show mean ± SE. Significant differences among different genotypes and nutrient conditions are indicated by letters (p < 0.05) as determined by ANOVA and Tukey post-hoc testing with pairwise P-values available in the Source Data file. The n values are shown below the respective groups.