Molecular analysis of alternative oxidase and ascorbic acid biosynthesis in two acerola clones (Malpighia emarginata DC) / Análise molecular da biossíntese alternativa de oxidase e ácido ascórbico em dois clones de acerola (Malpighia emarginata DC)

• Autor(a) principal: Saraiva, Luis Flávio Mendes
• Data de Publicação: 2021
• Outros Autores: Oliveira, Micheline Soares Costa, de Lima, Eliane Almeida, Mendes, Larissa Linhares Carvalho, Carneiro, Mirle Thais Aguiar, de Andrade, Ramyres Diego Lima, de Melo, José Hélio Costa and Dirce Fernandes
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Revista Veras
• Texto Completo: https://ojs.brazilianjournals.com.br/ojs/index.php/BRJD/article/view/29780
• topic: Acerola; Ascorbic acid; Alternative Oxidase.

The acerola, Malpiguia emarginata DC is a fruit small endowed with enviable nutritional qualities. The main feature that stands out from other species is its enormous capacity to synthesize ascorbic acid. For this study, we analyzed the gene expression of enzymes of the way Wheeler/Smirnoff well as the Alternative Oxidase (AOX). The last step this pathway ends in the inner mitochondrial membrane, due the presence of transmembrane enzyme L-Galactono -1,4 - Lactone dehydrogenase (L-GalLdh), located between the complex III and IV. Since the alternative oxidase is an enzyme uncoupling, no phosphorylating and insensitive to cyanide, present between the complexes II and III. This study aimed to identify the main gene expression responsible to biosynthesis of ascorbic acid and two isoforms of AOX (1 and 2), on flowers and fruits at different development stages, on two clones the acerola called Cereja and Roxinha. The determination of ascorbic acid levels was done by titration of Tillman, on two clone’s fruits. Total RNA from different tissues for two clones was isolated, and primers were used for semi-quantitative RT-PCR assays. To determine the multigene family for AOX, DNA genomic was isolated and degenerate primers were used on semi quantitative PCR. Specific and degenerate primers were used for gene expression the Wheeler/Smirnoff pathway. The ascorbic acid levels on both clones showed that the Roxinha clone had lower levels on all stages. The gene expression of three enzymes stood out from others, these showed a synergism with the expression levels of vitamin C contained in each tissue. In addition, gene expression in two clones showed differences in tissues that favor of Cereja clone. They are Mannose pyrophsphorylase, GDP-Mannose 3’5’ epimerase and GDP-Galactose phosphorylase. With greater emphasis on GDP-Mannose 3’5’ epimerase and GDP-Galactose phosphorylase. AOX1 gene expression increased on both clones during the fruit ripening, but revealed some differences. In green fruit of Cereja (C) clone the expression was lower than Roxinha (R), increasing the expression on unripe and ripe fruits. The AOX2 expression appeared constant during fruit ripening on Roxinha clone, increasing only in ripe fruit while on the Cereja clone the AOX2 gene expression gradually decreased with maturation.