Differential maternal supply of amino acids specifies contrasting compisition in soybean seeds

PAVLOVIC, TATIANA; MÜLLER, GABRIELA; POETA, FLORENCIA; SAENZ, EZEQUIEL; CALACE, PAULA; BORRÁS, LUCAS; SAIGO, MARIANA; GERRARD WHEELER, MARIEL C.

Congreso; RAFV XXXIII; 2021

Soybean is one of the most important oilseed crop, providing large amounts of vegetable protein and oil as feedstocks for food, feed, and industrial applications. The biosynthesis of seed reserves or filling depends on the transport of several carbon and nitrogen compounds generated through photosynthesis, which are received and metabolized by the developing embryo. The translocation is via phloem, but then the substrate transfer is apoplastic since there is no vascular connection between the seed coat and the embryo. Here, we reported a comparative characterization of the content of amino acids in the phloem unloading of two soybean recombinant inbred lines with different level of protein at the seeds. For this, the embryo was replaced in planta by sterile agar and the amino acid profile was assessed by phenylisothiocyanate derivatization followed by reverse phase-high performance liquid chromatography. Despite having similar genetic background, the contrasting lines exhibited differential amino acid composition throughout development. Most amino acids presented higher contents in the high-protein genotype than in the low-protein genotype. The largest supply of amino acids in the high-protein genotype could be supporting an enhanced synthesis of proteins for embryo development and reserve accumulation. This, together with the varying amino acid composition may partly explain the different strategies that each genotype has to obtain its contrasting amounts of reserves. Gain understanding on how the plants regulate the carbon flux to synthesize storage compounds is esential in order to provide biotechnological tools for obtaining high-quality soybean genotypes