Transcriptome-wide identification and screening of WRKY factors involved in the regulation of taxol biosynthesis in Taxus chinensis

Meng Zhang,Shengying Zhao,Lin Nie,Weifang Liao,Longjiang Yu,Chunhua Fu,Ying Chen,Xiaofei Jin

doi:10.1038/s41598-018-23558-1

Meng Zhang, Shengying Zhao + Show 6 more

Open Access

https://doi.org/10.1038/s41598-018-23558-1

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Abstract

WRKY, a plant-specific transcription factor family, plays important roles in pathogen defense, abiotic cues, phytohormone signaling, and regulation of plant secondary metabolism. However, little is known about the roles, functions, and mechanisms of WRKY in taxane biosynthesis in Taxus spp. In this study, 61 transcripts were identified from Taxus chinensis transcriptome datasets by using hidden Markov model search. All of these transcripts encoded proteins containing WRKY domains, which were designated as TcWRKY1–61. After phylogenetic analysis of the WRKY domains of TcWRKYs and AtWRKYs, 16, 8, 10, 14, 5, 7, and 1 TcWRKYs were cladded into Group I, IIa–IIe, and III, respectively. Then, six representative TcWRKYs were selected to classify their effects on taxol biosynthesis. After MeJA (methyl jasmonate acid) and SA (salicylic acid) treatments, all of the six TcWRKYs were upregulated by MeJA treatment. TcWRKY44 (IId) and TcWRKY47 (IIa) were upregulated, whereas TcWRKY8 (IIc), TcWRKY20 (III), TcWRKY26 (I), TcWRKY41 (IIe), and TcWRKY52 (IIb) were downregulated by SA treatment. Overexpression experiments showed that the six selected TcWRKYs exerted different effects on taxol biosynthesis. In specific, TcWRKY8 and TcWRKY47 significantly improved the expression levels of taxol-biosynthesis-related genes. Transcriptome-wide identification of WRKY factors in Taxus not only enhances our understanding of plant WRKY factors but also identifies candidate regulators of taxol biosynthesis.

Highlights

Taxol is the most effective chemotherapy medication used to treat many cancers, including ovarian, breast, lung, Kaposi sarcoma, cervical, and pancreatic[1]
For the identification of WRKY genes from T. chinensis, all known WRKY of A. thaliana and Oryza sativa were used as queries to perform local BLASTP search on the T. chinensis transcriptome datasets
Taxol is a precious secondary metabolite initially isolated from Taxus spp. and widely used as an anticancer drug

Summary

Introduction

Taxol is the most effective chemotherapy medication used to treat many cancers, including ovarian, breast, lung, Kaposi sarcoma, cervical, and pancreatic[1]. W-box, the specific cis-element binding with WRKY proteins, was detected in all of these promoter regions, indicating that WRKY plays important roles in the regulation of taxol biosynthesis[5,6]. All of the known WRKY factors could be divided into Group I to III according to the numbers of WRKY domains and their types of zinc finger motifs[7]. We observed that TcWRKY1 could interact with the promoter of the DBAT gene[6]. All of these results indicate that WRKY factors play important roles in taxol biosynthesis. Omics analysis has become an effective method to screen important transcription factors

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