While meager expression in nitrogen-poor medium was typical for genes functioning in protein synthesis and transcription, abundant expression was typical for genes coding for proteins involved in energy and genes of unknown function.
Also several development-related genes coding for embryo-abundant, senescence associated, ripening responsive or storage proteins were strongly enhanced.
In general, genes coding for transport proteins were more abundant in the atria than in the ventricles.
In particular, genes coding for ribosome constituents are extremely abundant, for example in cluster pairs #13, #14 and #18 of the LR-GA analysis, or in cluster pairs #14 and #24 of the BO-GA analysis.
For example, the genes coding for glycinin 3 and the most abundant Kunitz trypsin inhibitor are 46-fold and 6-fold less expressed in line R95-1705 compared to the average value from the nine lines.
The 20 most abundant differentially expressed genes at 35 DAP cover a narrower range of genes coding for 2S seed storage proteins, oleosins, cruciferins and protease inhibitor proteins.
The 20 most abundant differentially expressed genes at 23 DAP include 6 genes encoding proteases, 5 genes coding for protease inhibitor/seed storage/lipid transfer protein (LTP) family proteins and 2 genes coding for defensin-like family proteins.
The 13 differentially expressed genes during ZE included a vicilin gene, a putative gene for the sweet protein mabinlin, 3 genes coding for 21-kDa trypsin inhibitor proteins, and 7 genes encoding for Late Embryogenesis Abundant Proteins (LEA) (Additional file 16).
To identify the genes coding for MCP and CP, we first carried out SDS-PAGE analysis and showed that the two most abundant protein bands have molecular masses of 36.3 kD and 15.2 kD.
The mRNAs corresponding to genes coding for the high affinity glucose and maltose transporters (HXT2, HXT4, HXT7 and MAL31) typically induced by glucose limitation, were also found among the most abundant (Additional file 1: Table S1).
