Estabelecimento de cultivo in vitro e estudo proteômico de calos caulinares e foliares de Artocarpus incisa L.

Abstract

The species Artocarpus incisa, belonging to the Moraceae family, is a tree-sized plant with multiple applications in folk medicine. As a woody species, several difficulties are reported to its spread, such as the delay in its development and low germination rate. In vitro culture of plant tissue, in particular callus culture, can serve as a tool to overcome these difficulties and to facilitate obtaining the compounds of interest. This work was meant to provide the best conditions of callus formation as well as perform histological analysis and proteomic study of A. incisa calluses. For induction of callus, explants were used arising from leaf and shoot, which have been added to the nutritional formulation Woody Plant Medium (WPM), and applied in treatments containing PVP, activated charcoal, and different growth regulators (2,4-D, BAP, NAA and KIN). The results showed that the cultivation of shoot and leaf explants in medium with 0.1% activated charcoal, supplemented with 4.5 uM of 2,4-D and 4.4 uM BAP treatment was the best callus induction with an 88% percentage production. Quantification of proteins by Protein UV from NanoVue detected 15.97 ug protein / uL shoot extract; 20.07 ug protein / uL leaf extract; 0.75 ug protein / uL of shoot callus extract; and 16.85 ug protein / uL of leaf callus extract. The original tissues showed higher protein concentration than those in produced calluses, which can be explained by the differentiation of tissue. Histological analysis indicated that the cells of calluses were homogeneous and viable, with thin cell wall, and large amount of polysaccharide granules. The proteomic study by mass spectrometry led to the identification of peptides that have relation to previously reported plant proteins. We were able to detect proteins related to the defense (KM+, chitinase, catalase), metabolism (fructose-bisphosphate aldolase, glutamate carboxypeptidase) and cell signaling (calmodulin) in calluses, regardless of the origin of these. The work pioneered the proteomic study of A. incisa calluses, and is an initial step in understanding the biochemistry and physiology of the species under study.