Fisiologia Vegetal
URI permanente para esta coleçãohttps://locus.ufv.br/handle/123456789/185
Navegar
1 resultados
Resultados da Pesquisa
Item Photoperiod, salinity, and elicitors modulate the growth, morphophysiology, and biosynthesis of 20-hydroxyecdysone in Pfaffia glomerata (Spreng.) Pedersen(Universidade Federal de Viçosa, 2021-03-01) Fortini, Evandro Alexandre; Otoni, Wagner Campos; http://lattes.cnpq.br/8696085559149421Pfaffia glomerata is a plant widely used in traditional medicine, and a major producer of the secondary metabolite 20-hydroxyecdysone (20-E). Studies indicate that the biosynthesis of 20- E in P. glomerata can be regulated by abiotic stresses, but the mechanisms involved in this regulation are still unclear. Aiming to understand the physiological and molecular basis involved in the regulation of 20-E biosynthesis in P. glomerata, as affected by abiotic factors, ploidy level, and elicitation, three experiments were conducted. In the first experiment, plants of P. glomerata (accessions 22 and 43) were grown in vitro for 40 days under 4 different daily photoperiods: 4, 8, 16, and 24 h of light. We found that plants exhibited higher photosynthesis and biomass accumulation when grown in longer photoperiods. The plants also had anatomical and primary metabolism changes in response to the photoperiods tested, and the magnitude of these changes was accession-dependent. Furthermore, longer photoperiods promoted an increase in 20-E production, possibly as a result of higher carbon availability in the plants. In the second experiment, P. glomerata plants were grown in vitro and subjected to the following treatments: NaCl (50 mM), 5-azacytidine (5-azaC, 25 μM), and NaCl+5-azaC. After 40 days, we observed that the treatments promoted a significant reduction in growth and photosynthesis, as well as an increase in reactive oxygen species (ROS) and antioxidant enzyme production and an adjustment in primary metabolism. Through proteomic analyses, we identified differentially accumulated proteins mainly associated with the metabolism of carbohydrates, amino acids, and secondary metabolites, which may help us understand the salt stress and 5-azaC tolerance responses compared to control. Besides, we found that the 5-azaC and NaCl+5-azaC treatments reduced the accumulation of jasmonate biosynthesis-related protein, and this may contribute to reduced 20-E signaling and biosynthesis. In the third experiment, two different ploidies of P. glomerata (A22, diploid; and P28, a tetraploid derived from A22) were grown in vitro for 40 days, and the plants were elicited in the first 20 days with methyl jasmonate (methyl-JA) and methyl salicylate (methyl-SA). The elicitors induced contrasting anatomical modifications in P. glomerata leaves. Elicitation also reduced the photosynthetic rate of the plants, with a consequent change in primary metabolite content and reduction in growth. Treatments with methyl-JA and methyl-SA promoted oxidative stress, but also ROS mitigation by increasingantioxidant enzymes, and these changes were more significant in diploid plants. The production of 20-E was stimulated by elicitation with methyl-JA and was also higher in tetraploid plants. On the other hand, methyl-SA down-regulates Phantom gene expression, with a consequent reduction in 20-E biosynthesis. Taken together, our data provide important information on molecular, biochemical, and physiological mechanisms involved with the regulation of 20-E biosynthesis, as well as enable biotechnological strategies for increasing the production of this metabolite in P. glomerata plants grown in vitro. Keywords: Phytoecdysteroids. Abiotic stress. Photosynthesis. Medicinal plant. Proteomics. Phytohormones. Polyploidy.