An R2R3-MYB Transcription Factor Regulates Capsaicinoid Biosynthesis1[OPEN]
CaMYB31, an R2R3-MYB transcription factor, regulates the capsaicinoid biosynthetic pathway in chili pepper fruits and is regulated by plant hormones, wounding, temperature, and light. Capsaicinoids are responsible for the hot taste of chili peppers. They are restricted to the genus Capsicum and are...
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Published in | Plant physiology (Bethesda) Vol. 174; no. 3; pp. 1359 - 1370 |
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Main Authors | , |
Format | Journal Article |
Language | English |
Published |
American Society of Plant Biologists
08.05.2017
|
Online Access | Get full text |
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Summary: | CaMYB31, an R2R3-MYB transcription factor, regulates the capsaicinoid biosynthetic pathway in chili pepper fruits and is regulated by plant hormones, wounding, temperature, and light.
Capsaicinoids are responsible for the hot taste of chili peppers. They are restricted to the genus
Capsicum
and are synthesized by the acylation of the aromatic compound vanillylamine (derived from the phenylpropanoid pathway) with a branched-chain fatty acid by the catalysis of the putative enzyme capsaicinoid synthase. R2R3-MYB transcription factors have been reported in different species of plants as regulators of structural genes of the phenylpropanoid pathway; therefore, we hypothesized that MYB genes might be involved in the regulation of the biosynthesis of pungent compounds. In this study, an
R2R3-MYB
transcription factor gene, designated
CaMYB31
, was isolated and characterized in
Capsicum annuum
‘Tampiqueño 74’. Bioinformatic analysis suggested that
CaMYB31
could be involved in secondary metabolism, stress and plant hormone responses, and development.
CaMYB31
expression analysis from placental tissue of pungent and nonpungent chili pepper fruits showed a positive correlation with the structural genes
Ca4H
,
Comt
,
Kas
,
pAmt
, and
AT3
expression and also with the content of capsaicin and dihydrocapsacin during fruit development. However,
CaMYB31
also was expressed in vegetative tissues (leaves, roots, and stems). Moreover,
CaMYB31
silencing significantly reduced the expression of capsaicinoid biosynthetic genes and the capsaicinoid content. Additionally,
CaMYB31
expression was affected by the plant hormones indoleacetic acid, jasmonic acid, salicylic acid, and gibberellic acid or by wounding, temperature, and light, factors known to affect the production of capsaicinoids. These findings indicate that
CaMYB31
is indeed involved in the regulation of structural genes of the capsaicinoid biosynthetic pathway. |
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Bibliography: | M.L.A.-R. designed and carried out the experimental work, analyzed the data, and wrote the article; N.O.-A. designed, directed, and supervised the experiments and complemented and corrected the article. www.plantphysiol.org/cgi/doi/10.1104/pp.17.00506 The author responsible for distribution of materials integral to the findings presented in this article in accordance with the policy described in the Instructions for Authors (www.plantphysiol.org) is: Neftalí Ochoa-Alejo (nochoa@ira.cinvestav.mx). |
ISSN: | 0032-0889 1532-2548 |
DOI: | 10.1104/pp.17.00506 |