Transcriptome analysis and identification of key genes involved in 1-deoxynojirimycin biosynthesis of mulberry (Morus alba L.)

Dujun Wang; Li Zhao; Dan Wang; Jia Liu; Xiaofeng Yu; Yuan Wei; Zhen Ouyang

doi:10.7717/peerj.5443

Transcriptome analysis and identification of key genes involved in 1-deoxynojirimycin biosynthesis of mulberry (Morus alba L.)

PeerJ. 2018 Aug 23:6:e5443. doi: 10.7717/peerj.5443. eCollection 2018.

Authors

Dujun Wang^{1

2}, Li Zhao³, Dan Wang¹, Jia Liu¹, Xiaofeng Yu³, Yuan Wei³, Zhen Ouyang^{1

3}

Affiliations

¹ School of Food and Biological Engineering, Jiangsu University, Zhenjiang, China.
² College of Oceanology and Bioengineering, Yancheng Institute of Technology, Yancheng, China.
³ School of Pharmacy, Jiangsu University, Zhenjiang, China.

Abstract

Mulberry (Morus alba L.) represents one of the most commonly utilized plants in traditional medicine and as a nutritional plant used worldwide. The polyhydroxylated alkaloid 1-deoxynojirimycin (DNJ) is the major bioactive compounds of mulberry in treating diabetes. However, the DNJ content in mulberry is very low. Therefore, identification of key genes involved in DNJ alkaloid biosynthesis will provide a basis for the further analysis of its biosynthetic pathway and ultimately for the realization of synthetic biological production. Here, two cDNA libraries of mulberry leaf samples with different DNJ contents were constructed. Approximately 16 Gb raw RNA-Seq data was generated and de novo assembled into 112,481 transcripts, with an average length of 766 bp and an N50 value of 1,392. Subsequently, all unigenes were annotated based on nine public databases; 11,318 transcripts were found to be significantly differentially regulated. A total of 38 unique candidate genes were identified as being involved in DNJ alkaloid biosynthesis in mulberry, and nine unique genes had significantly different expression. Three key transcripts of DNJ biosynthesis were identified and further characterized using RT-PCR; they were assigned to lysine decarboxylase and primary-amine oxidase genes. Five CYP450 transcripts and two methyltransferase transcripts were significantly associated with DNJ content. Overall, the biosynthetic pathway of DNJ alkaloid was preliminarily speculated.

Keywords: 1-deoxynojirimycin; Biosynthesis; Key enzyme gene analysis; Mulberry; Transcriptomic.

Grants and funding

This work was supported by the National Natural Science Foundation of China (Grant No. 81573529, 81373480) and the Key project at central government level (2060302). There was no additional external funding received for this study. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.