Identification and characterization of seed storage proteins from native quinoa germplasm from Northwest Argentina

BARBERINI MARÍA LAURA; MARIA AGUSTINA MAZZELLA; BERTERO DANIEL; GROTEWOLD ERICH; MUSCHIETTI, JORGE

Buenos Aires

Congreso; Reunión conjunta de sociedades de biociencias; 2017

Quinoa (Chenopodium quinoa), a pseudocereal native to the Andean regions, is characterized mainly by the quality and nutritional value of its proteins due to an excellent balance of essential amino acids. However, different quinoa landraces exhibit different nutritional composition and morphological attributes. Therefore, we propose to perform comparative proteomics studies among different ecotypes of quinoa from Northwest Argentina (NWA) region to identify nutritional attributes and classify germplasm accessions. Initially, we optimized a two-dimensional gel electrophoresis (2-DE) protocol using commercial quinoa seeds from the southern Bolivian highlands, one of the most important areas of quinoa production. Two protein extraction methods, phenol/ammonium acetate (phenol method) and trichloroacetic acid/acetone (TCA method), were evaluated to determine their efficiency in separating quinoa proteins by 2-DE. The phenol method showed higher protein resolution and spot intensity of all proteins. Next, high-intensity spots were isolated, digested with trypsin and identified by MALDI-TOF/TOF mass spectrometry followed by in silico analysis. Most of the spots were identified as seed storage proteins and showed a high proportion of essential amino acids. On the other hand, we analyzed seeds amino acids profiles of native quinoa germplasm from NWA. We found differences among quinoa accessions for the amino acids studied. This variation in the amino acid content can be explained by genetic variability and/or environmental growth conditions. Thus, seed storage proteins and amino acid composition play a crucial role in determining the nutritional value of quinoa. Altogether, these results emphasize that the expression of quinoa seed storage proteins containing high proportions of essential amino acids is a potential strategy for the nutritional improvement of food crops.