Deciphering molecular determinants of the high levels of storage proteins and oil in the soybean seeds

ZUCCHETTI, J. I.; PAVLOVIC, T.; SAENZ, E.; BORRÁS, L.; SAIGO, M.; GERRARD WHEELER, M. C.

Rosario

Congreso; LIX Reunión Anual SAIB; 2023

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

Soybean is a strategic crop due to the accumulation of high-value molecules in the seeds. Currently, the agro-industrial sector is facing a sustained decrease in protein level, a situation that shows the need to pay attention not only to seed yield but also to seed quality. In order to gain knowledge on the molecular mechanism leading to the synthesis of reserves, two closely related soybean experimental lines with different protein and oil concentration were analyzed. For this purpose, total proteins were obtained from seeds at different development stages, which were identified and quantified by mass spectrometry. Numerous proteins with differential abundance among genotypes were detected (p < 0.05; average fold change > 2). Functional analysis revealed changes in photosynthesis, oxidative phosphorylation, protein processing, biosynthesis of secondary metabolites, sugar metabolism, among other processes. Interestingly, the most notable differences were observed in the later filling and desiccation stages, which have the greatest differences in storage protein content. A shutdown of specific activities of organic acid and amino acid metabolism was observed in the high-protein line, possibly driven by changes in the expression of regulatory genes related to abscisic acid signaling. Furthermore, some heat shock proteins, responsible for protein folding, were found in higher abundance in the high-protein line. These results clarified molecular mechanisms controlling compositional seed traits, and pointed out markers for breeding programs and/or targets for metabolic engineering.