Document Type
Article
Publication Date
2019
College/Unit
Davis College of Agriculture, Natural Resources and Design
Department/Program/Center
Division of Plant and Soil Sciences
Abstract
Background
Glyceollins are isoflavonoid-derived pathogen-inducible defense metabolites (phytoalexins) from soybean (Glycine max L. Merr) that have important roles in providing defense against pathogens. They also have impressive anticancer and neuroprotective activities in mammals. Despite their potential usefulness as therapeutics, glyceollins are not economical to synthesize and are biosynthesized only transiently and in low amounts in response to specific stresses. Engineering the regulation of glyceollin biosynthesis may be a promising approach to enhance their bioproduction, yet the transcription factors (TFs) that regulate their biosynthesis have remained elusive. To address this, we first aimed to identify novel abiotic stresses that enhance or suppress the elicitation of glyceollins and then used a comparative transcriptomics approach to search for TF gene candidates that may positively regulate glyceollin biosynthesis.
Results
Acidity stress (pH 3.0 medium) and dehydration exerted prolonged (week-long) inductive or suppressive effects on glyceollin biosynthesis, respectively. RNA-seq found that all known biosynthetic genes were oppositely regulated by acidity stress and dehydration, but known isoflavonoid TFs were not. Systemic acquired resistance (SAR) genes were highly enriched in the geneset. We chose to functionally characterize the NAC (NAM/ATAF1/2/CUC2)-family TF GmNAC42–1 that was annotated as an SAR gene and a homolog of the Arabidopsis thaliana (Arabidopsis) indole alkaloid phytoalexin regulator ANAC042. Overexpressing and silencing GmNAC42–1 in elicited soybean hairy roots dramatically enhanced and suppressed the amounts of glyceollin metabolites and biosynthesis gene mRNAs, respectively. Yet, overexpressing GmNAC42–1 in non-elicited hairy roots failed to stimulate the expressions of all biosynthesis genes. Thus, GmNAC42–1 was necessary but not sufficient to activate all biosynthesis genes on its own, suggesting an important role in the glyceollin gene regulatory network (GRN). The GmNAC42–1 protein directly bound the promoters of biosynthesis genes IFS2 and G4DT in the yeast one-hybrid (Y1H) system.
Conclusions
Acidity stress is a novel elicitor and dehydration is a suppressor of glyceollin biosynthesis. The TF gene GmNAC42–1 is an essential positive regulator of glyceollin biosynthesis. Overexpressing GmNAC42–1 in hairy roots can be used to increase glyceollin yields > 10-fold upon elicitation. Thus, manipulating the expressions of glyceollin TFs is an effective strategy for enhancing the bioproduction of glyceollins in soybean.
Digital Commons Citation
Jahan, Md Asraful; Harris, Brianna; Lowery, Matthew; Coburn, Katie; Infante, Aniello M.; Percifield, Ryan J.; Ammer, Amanda G.; and Kovinich, Nik, "The NAC family transcription factor GmNAC42–1 regulates biosynthesis of the anticancer and neuroprotective glyceollins in soybean" (2019). Faculty & Staff Scholarship. 1259.
https://researchrepository.wvu.edu/faculty_publications/1259
Source Citation
Jahan, M.A., Harris, B., Lowery, M. et al. The NAC family transcription factor GmNAC42–1 regulates biosynthesis of the anticancer and neuroprotective glyceollins in soybean. BMC Genomics 20, 149 (2019). https://doi.org/10.1186/s12864-019-5524-5
Comments
This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
This article received support from the WVU Libraries' Open Access Author Fund.