NanoLC-MS/MS protein analysis on laser-microdissected wheat endosperm tissues: A comparison between aleurone, sub-aleurone and inner endosperm

Wheat kernel proteins are not homogeneously distributed throughout the endosperm. The goal of this study was to investigate the relative differences in protein composition between the aleurone, sub-aleurone and inner endosperm. Using laser microdissection followed by nanoLC-MS/MS, an innovative method combining high spatial specificity and analytical selectivity in sample-limited situations, 780 proteins were detected and classified by function. A higher proportion of gluten proteins was detected in the sub-aleurone than inner endosperm. Composition-wise, gluten from the sub-aleurone is relatively more enriched in omega-gliadins but impoverished in LMW-GS and gamma-gliadins. While a basic set of albumins and globulins was detected in all three microdissected endosperm tissues, specific proteins, like puroindoline B, displayed a gradient. This study provides indications that both histological origin and relative positioning of the tissues drive the protein distribution. Knowledge of this protein distribution offers significant opportunities for the wheat manufacturing industry. Data available via ProteomeXchange, identifier PXD038743.

Automated summary

This study used laser microdissection and nanoLC-MS/MS to explore the relative differences in protein composition between different parts of wheat endosperm. The results showed that the sub-aleurone contained a higher proportion of gluten proteins than the inner endosperm, with differences in specific protein components.