Formation of α- and β-Cembratriene-Diols in Tobacco (Nicotiana tabacum L.) Is Regulated by Jasmonate-Signaling Components via Manipulating Multiple Cembranoid Synthetic Genes

Abstract

Cembranoids are a group of natural diterpenoid compounds with pharmaceutical potentials, and the cembratriene-diols produced by Nicotiana (tobacco) species display activities in anti-nicotine addiction and neuron protection. Although the enzymes catalyzing cembratriene-diols’ formation in tobacco have been investigated, the regulatory mechanism underlying this physiological process remains unknown. This study has investigated the roles of phytohormone jasmonic acid (JA) in regulating cembratriene-diol formation in N. tabacum cv. TN90 and found that JA and COI1, the receptor protein of the bioactive derivative of JA (i.e., JA-Ile), display critical roles in regulating cembratriene-diols’ formation and the expression of cembranoid synthetic genes CBTS, P450 and NtLTP1. Further studies showed that over-expressing either the gene encoding bHLH transcription factor MYC2a or that encoding MYB transcription factor MYB305 could upregulate the cembranoid synthetic genes and enhance the cembranoid production in plants with dysfunction of COI1. Further studies suggest that COI1 and its downstream regulators MYC2a and MYB305 also modulate the trichome secretion, which is correlated with cembranoid formation. Taken together, this study has demonstrated a critical role of JA-signaling components in governing the cembratriene-diol formation and the transcription of cembratriene-diol synthetic genes in tobacco. Findings in this study are of great importance to reveal the molecular regulatory mechanism underlying cembranoid synthesis.

1H‐NMR metabolomics profiling of recombinant tobacco plants holding a promoter of a sesquiterpene cyclase

“…Additionally, cembratriene‐4,6‐diol is a protective molecule with antitumour activity and is found in the cigarette smoke condensate. This diterpenoid also exhibits anti‐nicotine addiction properties and neuroprotective activity . The metabolic divergences suggest that key biosynthetic pathways are apparently modified in transgenic samples.…”

Synthesis of cembratriene-ol and cembratriene-diol in yeast via the MVA pathway

“…This kind of compounds were firstly identified in conifer plants and have been found to widely present in nature [ 1 , 2 ]. So far, hundreds of cembranoids have been isolated from plants, insects, alligators, and marine organisms [ 3 , 4 ]. Cembranoids possess multiple bioactivities, such as anti-fungal [ 5 – 7 ], anti-insect [ 8 ], anti-cancer [ 9 , 10 ], anti-inflammatory [ 11 – 13 ], neuroprotection [ 14 , 15 ], etc.…”

“…Cembratriene-ol (CBT-ol) and cembratriene-diol (CBT-diol) are two major cembranoids in tobacco. And, they are synthesized and secreted by the glandular trichomes of tobacco [ 3 ].…”

Extraction, purification and anti-TMV effects of α (β)-2,7,11-cembratriene-4,6-diol from tobacco leaves

“…It is The copyright holder for this preprint this version posted June 1, 2021. ; https://doi.org/10.1101/2021.06.01.446537 doi: bioRxiv preprint Proteus vulgaris) [15,16]. Interestingly, in response to tobacco mosaic virus infection, a substantial increase in cembranoids, in particular α/β-CBD, has been achieved with systemic acquired resistance (SAR) leaves [17,18]. However, it is scarcely examined whether the exogenous application of α(β)-CBD has inhibitory effects on tobacco virus infection or not.…”

“…In addition to exhibiting suppression in spore germination of many fungal diseases ( Peronospora tabacina, Colletotrichum lagenarium, Candida albicans, Fusarium chlamydosporum, Aspergillus niger and Alternaria alternata ), exogenously applied α(β)-CBD also inhibited the growth of bacteria ( Staphylococcus aureus , Bacillus subtilis and Proteus vulgaris )[15,16]. Interestingly, in response to tobacco mosaic virus infection, a substantial increase in cembranoids, in particular α/β-CBD, has been achieved with systemic acquired resistance (SAR) leaves[17,18]. However, it is scarcely examined whether the exogenous application of α(β)-CBD has inhibitory effects on tobacco virus infection or not.…”