| Title: | A Hedychium coronarium short chain alcohol dehydrogenase is a player in allo-ocimene biosynthesis |
| Author(s): | Chen H; Yue Y; Yu R; Fan Y; |
| Address: | "Department of Landscape Architecture, College of Life Science, Zhaoqing University, Zhaoqing Avenue, Duanzhou District, Zhaoqing, 526061, China. The Research Center for Ornamental Plants, College of Horticulture, South China Agricultural University, No. 483 Wushan Road, Tianhe District, Guangzhou, 510642, China. The Research Center for Ornamental Plants, College of Horticulture, South China Agricultural University, No. 483 Wushan Road, Tianhe District, Guangzhou, 510642, China. fanyanping@scau.edu.cn. Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, South China Agricultural University, Wushan Road, Guangzhou, 510642, China. fanyanping@scau.edu.cn" |
| DOI: | 10.1007/s11103-019-00904-z |
| ISSN/ISBN: | 1573-5028 (Electronic) 0167-4412 (Linking) |
| Abstract: | "An enzyme is crucial for the formation of Hedychium coronarium scent and defense responses, which may be responsible for the biosynthesis of allo-ocimene in H. coronarium. Hedychium coronarium can emit a strong scent as its main scent constituents are monoterpenes and their derivatives. Among these derivatives, allo-ocimene is not only a very important volatile substance in flower aroma, but is also crucial to plant defense. However, the molecular mechanism of allo-ocimene biosynthesis has not been characterized in plants. In this study, a new alcohol dehydrogenase gene, HcADH, was cloned. The amino acid sequences encoded by HcADH contained the most conserved motifs of short chain alcohol dehydrogenase/reductases (SDRs), which included NAD(+) binding domain, TGxxx[AG]xG and active site YxxxK. Real-time PCR analyses showed that the HcADH was highly expressed in the outer labellum but was almost undetectable in vegetative organs. The change in its expression level in petals was positively correlated with the emission pattern of allo-ocimene during flower development. HcADH expression coincides also the release level of allo-ocimene among different Hedychium species. Although HcADH is not expressed in the leaves, HcADH expression and allo-ocimene release in leaves can be induced by mechanical wounding or methyl jasmonate (MeJA) treatment. In addition, the expression of HcADH induced by mechanical wounding can be prevented by acetylsalicylic acid, a jasmonic acid biosynthesis inhibitor, suggesting that jasmonic acid might participate in the transmission of wounding signals. Using the Barley stripe mosaic virus (BSMV)-VIGS method, it was found that BSMV:HcADH(335) inoculation was able to down-regulate HcADH expression, decreasing only the release of allo-ocimene in flowers while the content of other volatile substances did not decrese. In vitro characterization showed that recombinant HcADH can catalyze geraniol into citral, and citral is an intermediate of allo-ocimene biosynthesis. HcADH may be responsible for the biosynthesis of allo-ocimene in H. coronarium, which is crucial for the formation of H. coronarium scent and defense function" |
| Keywords: | "Acetates/metabolism Acyclic Monoterpenes Cyclopentanes/metabolism Flowers/enzymology Gene Expression Profiling Gene Expression Regulation, Plant Oxylipins/metabolism Plant Proteins/genetics/*metabolism Polyenes/*metabolism Short Chain Dehydrogenase-Reduct;" |
| Notes: | "MedlineChen, Hua Yue, Yuechong Yu, Rangcai Fan, Yanping eng 30972026/National Natural Science Foundation of China/ 31370694/National Natural Science Foundation of China/ 31600573/National Natural Science Foundation of China/ 2009-356/the Guangdong-industry Technology Research System/ KBL11008/Key Laboratory of Innovation and Utilization for Germplasm Resources in Horticultural Crops/ 20134404110016/a Specialized Research Fund for the Doctoral Program of Higher Education of China/ 2017KTSCX196/the Key platform and scientific research project of Guangdong Education Department/ Netherlands 2019/08/02 Plant Mol Biol. 2019 Oct; 101(3):297-313. doi: 10.1007/s11103-019-00904-z. Epub 2019 Jul 31" |
