Metabolic profile, ultrastructure and gene expression of brazilian-ginseng [Pfaffia glomerata (Spreng.) Pedersen] under photoautotrophic growth and interaction with nematodes

• Ano de defesa: 2017
• Autor(a) principal: Ferreira, Peracio Rafael Bueno
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Universidade Federal de Viçosa
• Palavras-chave em Português: Pfaffia glomerata - Biossíntese; Nematoide; 20-Hidroxiecdisona; Fisiologia Vegetal
• Link de acesso: https://locus.ufv.br//handle/123456789/27559

Pfaffia glomerata is a plant whose importance comes to the active constituent 20- hydroxiecdysone (20E), an important phytoecdisteroid. 20E is similar to insect molting hormones, however, it is still poorly understood how plants produce 20E. Here, the content of 20E in P. glomerata was assessed in plants grown under in vitro photoautotrophic conditions or challenged with the nematode Meloidogyne javanica, under greenhouse conditions. The aim of this work was understand the biosynthesis of 20E in two accessions of P. glomerata (Ac 22 and 43) by means of metabolomics, ultrastructure and expression of two 20E biosynthesis-related genes. We verified that photoautotrophy system was efficient to stimulate the production of 20E under CO2 enrichment (1000 μL L-1) combined with Florialite® as supporting material. Florialite® led to well-developed chloroplast strucuture and increasing of morphometric measures. Interestingly, the photoautotrophic system influenced on photosynthesis intermediates (amino acids, sugars, and TCA), stress-(aromatic amines and shikimate), osmotic adjustment-related compounds (hydroxyproline, aspartate and myo-inositol). Markedly, urea seems to be a biomarker for low photoautotrophic conditions. The nematodes reduced many central metabolites of Ac 43 (notably organic acids), and accumulated important amino acids for nematode nutrition (isoleucine and valine). Ac 22, by its turn, accumulated sugars that are stress indicators and closely involved on the maturation of the nematodes. Notwithstanding, the Halloween genes (Phantom and Spook), only reported in insects, were expressed in P. glomerata and were influenced by nematode interaction, increasing expression on Ac 43 infected by nematode and increasing content of 20E. Conversely, Phantom and Spook were downregulated in Ac 22 infected with nematodes. The infection of nematode causes damage-induced accumulation of 20E in accessions of Pfaffia glomerata and that accumulation was modulated by the phantom and spook genes and by differences on metabolome. We infered that metabolism of Pfaffia glomerata accessions 22 and 43 is characterized by distinct metabolic signatures under photoautrophic system and with nematode interaction.