Screening e identificação molecular de microrganismos endofíticos produtores de triterpenos em Quillaja lancifolia D. Don

Abstract

Saponins are bioactive compounds of interest to various industries due to their unique properties of adjuvancy in vaccines, surfactant activities, anti-inflammatory, and anticancer properties. The triterpenic saponins of species belonging to the genus Quillaja prolong and intensify humoral and cellular immune responses when added to human and veterinary vaccines, creating a growing demand for more productive, sustainable, and scalable sources for such compounds. In plants, endophytes are microorganisms that inhabit the interior of plant tissues without causing pathologies under homeostatic conditions, and they may be responsible for physiological modulation under stress conditions and chemical elicitation - when specialized metabolic pathways are co-expressed between endophyte and host plant. Here, screening and molecular identification of triterpenic saponin-producing microorganisms from Quillaja lancifolia were performed, aiming to contribute to the recognition of new producing sources and to expand knowledge on the microbial and biochemical diversity of endophytes. A total of 42 strains of endophytic microorganisms (22 fungi and 20 bacteria) were isolated from seeds, seedlings, calli, and cell suspensions of Q. lancifolia, and they were tested for triterpenic saponin production through TLC 3 Thin Layer Chromatography, foam differential production test, and determination of total saponins yield. Four selected strains potentially producing triterpenes (four fungi) were molecularly identified using sequencing of the DNA from the ITS- 1 region, after amplification through the Polymerase Chain Reaction (PCR) technique. Diplodia sp., Acremonium sp., Fusarium sp., and Aureobasidium sp. were identified as triterpenic saponin-producing endophytes in bands stained with sulfuric anisaldehyde in TLC, with saponin yields of 3.0%, 0.74%, 0.40%, and 6.28% (m/m), respectively, while the plant exhibited 2.0%. Besides the plant, cultures of Q. lancifolia endophytes can provide an alternative platform for the production of triterpenic saponins, with molecular biology and bioinformatics tools being indispensable for the bioprospecting process.