Figure 8.

Nitrate Reallocation Mediated by the ET/JA-NRT Signaling Module Reduces Root Growth under the Nonstressed Condition.

Seedlings of ctr1-8, eto1-1, coi1-1, ctr1-8 nrt1.8-2, and eto1-1 nrt1.8-2 mutants and their wild-type control Col-0 were germinated and allowed to grow vertically for 7 to 9 d on medium supplemented with 2.25 mM ammonium (2.25 NH₄⁺), 2.25 mM nitrate (2.25 NO₃⁻), or 25 mM nitrate (25 NO₃⁻), followed by measurement of root growth. Relative root growth of each mutant was calculated by normalizing the data to those of their wild-type control, except for (C).

(A) and (B) Relative root growth of ctr1-8 (A) and eto1-1 (B) against the wild-type Col-0 under different conditions. Values are means ± se; n = 5.

(C) Seeds from heterologous coi1-1(+/−) plants were plated on medium with 10 μM MeJA to screen homozygous seedlings, which together with Col-0 were incubated with different nitrogens plus 10 μM MeJA to mimic the constitutive JA response; correspondingly, the relative growth is defined as the ratio of coi1-1(+/+) to Col-0. Values are means ± se; n = 5.

(D) and (E) Root growth of ctr1-8 and ctr1-8 nrt1.8-2 (D) or eto1-1 and eto1-1 nrt1.8-2 (E) under different conditions. Values are means ± sd; n = 9 to 11.