Análise proteômica do haustório e endosperma durante a mobilização de reservas das sementes de açaí (Euterpe oleracea Mart.)

Abstract

The açaí tree (Euterpe oleracea Mart., Arecaceae family) has great economic value due to its pulp. This production generates a residue of more than one million tons of seeds accumulated annually in the Amazon region. Therefore, understanding how E. oleracea mobilizes seed reserves is a fundamental step towards establishing biotechnological strategies for the use of pulp production residue. The objective of this work was to study the mobilization of reserves during germination of E. oleracea using morphoanatomical and proteomic approaches. The haustorium was evaluated for anatomical changes that may be related to the mobilization of reserves in the endosperm. Proteomic analysis used samples from haustorium tissues (HA1, HA2, HA3 and HA4), endosperm (EN1, EN2 and EN3) and digestion zone (DZ2 and DZ3). Extracted proteins were hydrolyzed with trypsin and peptides were analyzed in nLC-MS/MS Orbitrap based systems. The obtained results were evaluated with Xcalibur v software. 2.2, Proteome Discoverer v. 2.4 and Perseus v. 1.6.14. Anatomical analysis showed that the development of the digestion zone in the endosperm coincides with the differentiation of the vascular system in the haustorium showing that endosperm degradation and haustorium development are closely regulated. Proteomic analysis identified 2447, 1887 and 1540 proteins for haustorium, endosperm and digestion zone, respectively. The results showed that a variety of hydrolases related to mannan mobilization increase in abundance to the digestion zone in relation to the endosperm and with the development of the haustorium. This pattern of abundance suggests that the hydrolases involved in the mobilization of reserves are synthesized during endosperm digestion by the endosperm and/or haustorium and transported to the digestion zone and not only accumulated in the mature seed and activated with germination. This work shows that the haustorium plays an active role in the mobilization of endosperm reserves and its role is not just the transport of reserves to the seedling.