Figure 4.

N‐metabolites rather than NH₄ ⁺ regulate rice resistance to ShB. (a, b, c, d) Leaves from GS1;1 mutant (gs1;1), GS1;1 rice overexpression lines (OX1 and OX2), AMT1;1 OX1, AMT1;1 OX1/gs1:1 and together with their wild‐type plants were challenged with R. solani AG1‐IA. The corresponding statistical results of the lesion area were calculated. Six leaves from each line were analysed, and the experiments were repeated three times. Data represent the means ± standard error (SE) (n > 10). Significant differences at P < 0.05 are indicated by different letters. (e) Endogenous NH₄ ⁺ levels in gs1;1, AMT1;1 OX1, AMT1;1 OX1/gs1;1 and wild‐type plants were measured in roots grown in 0.5 × MS for 3 days. (f, g) R. solani AG1‐IA was cultured on a Czapek–Dox medium with the addition of different concentrations of amino acids (glutamic acid and aspartic acid), and the colony diameter (with original cake diameter) was measured after 48 hours. The experiments were repeated at least ten times. Data represent means ± standard error (SE) (n > 10). Significant differences at P < 0.05 are indicated by different letters. (h) Glutamate and glutamine concentrations were measured from 10‐day‐old wild‐type, AMT1;1 OX1 and AMT RNAi plant leaves grown in hydroponics for 4 weeks with a spectrophotometric method. Data represent the means ± standard error (SE) (n > 10).