Shikimate Kinase Plays Important Roles in Anthocyanin Synthesis in Petunia
In plants, the shikimate pathway is responsible for the production of aromatic amino acids L-tryptophan, L-phenylalanine, and L-tyrosine. L-Phenylalanine is the upstream substrate of flavonoid and anthocyanin synthesis. Shikimate kinase (SK) catalyzes the phosphorylation of the C3 hydroxyl group of...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2022-12-01
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| Series: | International Journal of Molecular Sciences |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1422-0067/23/24/15964 |
| Summary: | In plants, the shikimate pathway is responsible for the production of aromatic amino acids L-tryptophan, L-phenylalanine, and L-tyrosine. L-Phenylalanine is the upstream substrate of flavonoid and anthocyanin synthesis. Shikimate kinase (SK) catalyzes the phosphorylation of the C3 hydroxyl group of shikimate to produce 3-phosphate shikimate (S3P), the fifth step of the shikimate pathway. However, whether SK participates in flavonoid and anthocyanin synthesis is unknown. This study characterized the single-copy <i>PhSK</i> gene in the petunia (<i>Petunia hybrida</i>) genome. <i>PhSK</i> was localized in chloroplasts. <i>PhSK</i> showed a high transcription level in corollas, especially in the coloring stage of flower buds. Suppression of <i>PhSK</i> changed flower color and shape, reduced the content of anthocyanins, and changed the flavonoid metabolome profile in petunia. Surprisingly, <i>PhSK</i> silencing caused a reduction in the shikimate, a substrate of <i>PhSK</i>. Further qPCR analysis showed that <i>PhSK</i> silencing resulted in a reduction in the mRNA level of <i>PhDHQ/SDH</i>, which encodes the protein catalyzing the third and fourth steps of the shikimate pathway, showing a feedback regulation mechanism of gene expression in the shikimate pathway. |
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| ISSN: | 1661-6596 1422-0067 |