CRF4 overexpression represses high-affinity nitrate uptake and biomass in planta. (A) CRF4 overexpression via β-estradiol (+βE) induction (35) represses SNZ, CDF1, and NRT2.1 (SI Appendix, Fig. S13C and Dataset S1, Table S5). SNZ and CDF1 overexpression in shoot cells (36) induces NRT2.1 expression (Dataset S1, Tables S6 and S7). CRF4 overexpression in low-N (1 mM NO3) conditions significantly reduces (B) the rate of nitrate 15NO3− uptake (Dataset S1, Table S16) and (C) shoot biomass in planta (SI Appendix, Fig. S13A). N.S, not significant.