Comparative Proteomics Analysis of Selenium Responses in Selenium-Enriched Rice Grains

By foliar fortification with selenite, selenium (Se)-enriched
rice
with a higher Se content and grain yield has been generated. However,
the regulatory mechanisms of Se response in rice grains remain unknown;
therefore, we carried out a comparative proteomics study in Se-enriched
rice grains by using two approaches including two-dimensional gel
electrophoresis (2-DE)-coupled MALDI-TOF/TOF MS and 1-DE/LC–FTICR–MS-coupled
label-free quantification. By comparison between Se treatment and
control, 62 and 250 abundance changed proteins were identified from
2-DE and 1-DE, respectively. By functional classification, proteins
involved in metabolism, cell redox regulation, and seed nutritional
storage were the most highly affected by Se accumulation. The up-regulation
of late embryogenesis abundant proteins as well as proteins involved
in sucrose synthesis and other metabolism pathways may contribute
to the earlier maturation and higher yield of the Se-enriched rice.
In addition, there have been six proteins identified to contain selenoamino
acid modification, which is the first identification of selenoproteins
in higher plants. In conclusion, our study provided novel insights
into Se response in rice grains at the proteome level, which are expected
to be highly useful for dissecting the Se response pathways in rice
and for the production of Se-enriched rice in the future.