Understanding the molecular basis of differential grain protein accumulation in wheat (Triticum aestivum L.) through expression profiling of transcription factors related to seed nutrients storage.

Increasing nutritional value of cereals is one of the important research and breeding objectives to overcome malnutrition in developing countries. The synthesis of grain seed proteins during grain filling is controlled by several mechanisms including transcriptional and posttranscriptional modifications. In the current investigation, transcript abundance analysis of three allelic variants of seed storage protein activator (Spa A, Spa B and Spa D) and NAM-B1 affecting seed nutrient concentration was carried out in two genotypes (UP 2672 and HS 540) of bread wheat differing in grain protein content. Expression profiling of transcription factor genes was performed using quantitative real time PCR (qRT-PCR). Positive correlation and significant p value > 0.05 was observed among the fold expression in developing stages of both the genotypes. Maximum expression of Spa genes was observed at S3 stage and maximum fold expression was observed for Spa B gene in case of UP 2672, the genotype with high protein content. The transcript profiling of NAM-B1 gene revealed threefold higher expression in UP 2672 than that of HS 490 at S4 stage. The findings revealed the role of transcriptional regulation in differential grain protein accumulation through varied expression and existence of their allelic variants in wheat genotypes.