Semi-quantitative RT-PCR analysis of GS2 trancripts in different organs of the plant. Total RNA was extracted from roots of plants growing on ammonium nitrate (1), roots of plants growing in symbiosis with S. meliloti (2), 14 day old nodules (3), leaves (4), stems (5), cotyledons from light grown seedlings (6), cotyledons from dark grown seedlings (7), flowers (8), pods (9) and developing seeds collected at 20 DAP (10). 50 ng of cDNA was used in each assay. Transcript levels for MtGS2a, MtGS2b-α, MtGS2b-β and the elongation factor 1-a (elf1-a), as internal reference gene are shown. Values correspond to quantified band intensities of GS2 relative to the housekeeping gene elf1-α.