The late-flowering phenotype of nrt1.13 is more severe under
low-nitrate conditions. (A) Schematic of the T-DNA insertion site of the
nrt1.13 mutant. In nrt1.13, the T-DNA was inserted
into the fourth exon. Black boxes, coding region; white boxes, untranslated region; F
and R, the forward and reverse primer, respectively, used for genomic DNA PCR and
RT-PCR; LB, left border primer of T-DNA. (B) Genomic DNA PCR and RT-PCR analyses of
nrt1.13. Total RNA was obtained from petioles of indicated plants.
HIS3, the internal control of RT-PCR. (C) Photo of 43-day-old
plants grown hydroponically with 2 or 0.2 mM nitrate.
PNRT1.13:NRT1.13-GFP/nrt1.13 #1 and #2
are two independent complementation lines. (D) and (E) Flowering time of plants grown
under normal (2 mM) and low (0.2 mM) nitrate, indicated as days after sowing (D) or
measured as the number of rosette leaves at bolting (E). Values are means ± SE of 25
independent plants. Statistical analysis comprised one-way ANOVA with a Tukey
post hoc test (P<0.05; Supplemental Data set 1).
Similar results were obtained in four independent experiments. (F) Expressions of
FLC, CO, FT,
SOC1, and LFY measured by RT-qPCR. Total RNA was
isolated from whole leaves of 25-day-old plants supplied with 0.2 mM nitrate. Values
are the means ± SE of three independent samples. Statistical analysis comprised
one-way ANOVA with a Tukey HSD post hoc test
(P < 0.05). Similar results were obtained from two additional
experiments.