Fig. 7
Expression levels (FPKM) of genes encoding glutamine synthetases GS1, GSr1 and GS2 in the embryo and endosperm of developing grain from wheat (Triticum aestivum) genotypes Spark and SR3. The plants were grown with sulphur either supplied (+) or withheld (−). Results for each homeologue are shown separately, as indicated. a Embryo, 14 dpa. b Endosperm, 14 dpa. c Embryo, 21 dpa. d Endosperm, 21 dpa. Gene reference numbers are given in Additional file 2. The increase in expression of the 4AL and 6BL homeologues in the endosperm in SR3 at 14 dpa in response to sulphur deficiency was significant (p = 0.00113 and 0.0299, respectively), as was the increase in expression of the 6AL and 6BL homeologues in the embryo of SR3 at 21 dpa (p = 0.0401 and 0.0164, respectively). In the endosperm at 21 dpa, the decrease in expression of the 6AL, 6BL, 6DL, 4DS, 4AL and 1AL genes in SR3 in response to sulphur deficiency was significant (p < 0.001 for 1AL, 6AL, 4BS and 4DS; p = 0.01961 for 6BL and 0.04599 for 6 DL)