Figure 4.

Northern blot analysis of expression of the PRH genes in A. thaliana. (Upper Left) Total leaf (L), root (R), and stem (S) RNA was extracted from 21-day-old compost-grown plants grown under normal sulfur nutrition. (Upper Right) Total RNA was extracted from A. thaliana plants growing in liquid shake culture in MS medium with 1.6 mM sulfate (+ SO₄⁻) or deprived of sulfate for 48h (− SO₄⁻). RNA was hybridized with gene-specific probes derived from the 5′ end of Prh-19, Prh-23, and Prh-43 cDNAs, respectively. (Lower) RNA was hybridized with the chalcone synthase probe (35) and with an 18S rRNA probe (36).