Publicação
Exogenous application of non-mature miRNA-encoded miPEP164c inhibits proanthocyanidin synthesis and stimulates anthocyanin accumulation in grape berry cells
| Resumo: | Secondary metabolic pathways in grape berries are tightly regulated by an array of molecular mechanisms, including microRNA-mediated post-transcriptional regulation. As recently discovered, before being processed into mature microRNAs (miRNAs), the primary transcripts of miRNAs (pri-miRNAs) can encode for small miRNA-encoded peptides (micropeptides miPEPs) that ultimately lead to an accentuated downregulation of the respective miRNA-targeted genes. Although few studies about miPEPs are available, the discovery of miPEPs reveals a new layer of gene regulation at the post-transcriptional level that opens the possibility to regulate plant metabolism without resorting to gene manipulation. Here, we identified a miPEP encoded in non-mature miR164c putatively targeting grapevine transcription factor VvMYBPA1 (miPEP164c/miPEP-MYBPA1), a positive regulator of key genes in the proanthocyanidin (PA)-biosynthetic pathway, a pathway that competes directly for substrate with the anthocyanin-biosynthetic pathway. Thus, the objective of this work was to test the hypothesis that the exogenous application of miPEP164c (miPEP-MYBPA1) can modulate the secondary metabolism of grape berry cells by inhibiting PA biosynthetic pathway while simultaneously stimulating anthocyanin synthesis. The exogenous application of miPEP164c to suspension-cultured cells from grape berry (cv. Gamay) enhanced the transcription of its corresponding non-mature miR164c, with a maximum effect at 1 M and after a period of 10 days, thus leading to a more pronounced post-transcriptional silencing of its target VvMYBPA1. This led to a significant inhibition of the PA pathway, mostly via inhibition of leucoanthocyanidin reductase (LAR) and anthocyanidin reductase (ANR) enzymatic activities and VvLAR1 downregulation. In parallel, the anthocyanin-biosynthetic route was stimulated. Anthocyanin content was 31% higher in miPEP164c-treated cells, in agreement with the observed upregulation of VvUFGT1 transcripts and UFGT enzyme activity levels. |
|---|---|
| Autores principais: | Vale, Mariana |
| Outros Autores: | Rodrigues, Jéssica; Badim, Hélder; Gerós, H.; Conde, Artur |
| Assunto: | Anthocyanins Grape berry secondary metabolism miRNA regulation Non-mature miRNA-encoded peptide Post-transcriptional regulation |
| Ano: | 2021 |
| País: | Portugal |
| Tipo de documento: | artigo |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade do Minho |
| Idioma: | inglês |
| Origem: | RepositóriUM - Universidade do Minho |
| Resumo: | Secondary metabolic pathways in grape berries are tightly regulated by an array of molecular mechanisms, including microRNA-mediated post-transcriptional regulation. As recently discovered, before being processed into mature microRNAs (miRNAs), the primary transcripts of miRNAs (pri-miRNAs) can encode for small miRNA-encoded peptides (micropeptides miPEPs) that ultimately lead to an accentuated downregulation of the respective miRNA-targeted genes. Although few studies about miPEPs are available, the discovery of miPEPs reveals a new layer of gene regulation at the post-transcriptional level that opens the possibility to regulate plant metabolism without resorting to gene manipulation. Here, we identified a miPEP encoded in non-mature miR164c putatively targeting grapevine transcription factor VvMYBPA1 (miPEP164c/miPEP-MYBPA1), a positive regulator of key genes in the proanthocyanidin (PA)-biosynthetic pathway, a pathway that competes directly for substrate with the anthocyanin-biosynthetic pathway. Thus, the objective of this work was to test the hypothesis that the exogenous application of miPEP164c (miPEP-MYBPA1) can modulate the secondary metabolism of grape berry cells by inhibiting PA biosynthetic pathway while simultaneously stimulating anthocyanin synthesis. The exogenous application of miPEP164c to suspension-cultured cells from grape berry (cv. Gamay) enhanced the transcription of its corresponding non-mature miR164c, with a maximum effect at 1 M and after a period of 10 days, thus leading to a more pronounced post-transcriptional silencing of its target VvMYBPA1. This led to a significant inhibition of the PA pathway, mostly via inhibition of leucoanthocyanidin reductase (LAR) and anthocyanidin reductase (ANR) enzymatic activities and VvLAR1 downregulation. In parallel, the anthocyanin-biosynthetic route was stimulated. Anthocyanin content was 31% higher in miPEP164c-treated cells, in agreement with the observed upregulation of VvUFGT1 transcripts and UFGT enzyme activity levels. |
|---|