Comparative Metabolomics Profiling Reveals Key Metabolites and Associated Pathways Regulating Tuber Dormancy in White Yam (Dioscorea rotundata Poir.)

Jeremiah S Nwogha; Abtew G Wosene; Muthurajan Raveendran; Jude E Obidiegwu; Happiness O Oselebe; Rohit Kambale; Cynthia A Chilaka; Veera Ranjani Rajagopalan

doi:10.3390/metabo13050610

Comparative Metabolomics Profiling Reveals Key Metabolites and Associated Pathways Regulating Tuber Dormancy in White Yam (Dioscorea rotundata Poir.)

Metabolites. 2023 Apr 28;13(5):610. doi: 10.3390/metabo13050610.

Authors

Jeremiah S Nwogha^{1

2

3}, Abtew G Wosene¹, Muthurajan Raveendran², Jude E Obidiegwu³, Happiness O Oselebe⁴, Rohit Kambale², Cynthia A Chilaka⁵, Veera Ranjani Rajagopalan²

Affiliations

¹ Department of Horticulture and Plant Sciences, College of Agriculture and Veterinary Medicine, Jimma University, Jimma P.O. Box 307, Ethiopia.
² Centre for Plant Molecular Biology & Biotechnology, Departments of Plant Biotechnology and Biochemistry, Tamil Nadu Agricultural University, Coimbatore 641003, India.
³ Yam Research Programme, National Root Crops Research Institute, Umudike 440001, Nigeria.
⁴ Department of Crop Production and Landscape Management, Ebonyi State University, Abakaliki 480282, Nigeria.
⁵ Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, 19 Chlorine Gardens, Belfast BT9 5DL, UK.

Abstract

Yams are economic and medicinal crops with a long growth cycle, spanning between 9-11 months due to their prolonged tuber dormancy. Tuber dormancy has constituted a major constraint in yam production and genetic improvement. In this study, we performed non-targeted comparative metabolomic profiling of tubers of two white yam genotypes, (Obiaoturugo and TDr1100873), to identify metabolites and associated pathways that regulate yam tuber dormancy using gas chromatography-mass spectrometry (GC-MS). Yam tubers were sampled between 42 days after physiological maturity (DAPM) till tuber sprouting. The sampling points include 42-DAPM, 56-DAPM, 87DAPM, 101-DAPM, 115-DAPM, and 143-DAPM. A total of 949 metabolites were annotated, 559 in TDr1100873 and 390 in Obiaoturugo. A total of 39 differentially accumulated metabolites (DAMs) were identified across the studied tuber dormancy stages in the two genotypes. A total of 27 DAMs were conserved between the two genotypes, whereas 5 DAMs were unique in the tubers of TDr1100873 and 7 DAMs were in the tubers of Obiaoturugo. The differentially accumulated metabolites (DAMs) spread across 14 major functional chemical groups. Amines and biogenic polyamines, amino acids and derivatives, alcohols, flavonoids, alkaloids, phenols, esters, coumarins, and phytohormone positively regulated yam tuber dormancy induction and maintenance, whereas fatty acids, lipids, nucleotides, carboxylic acids, sugars, terpenoids, benzoquinones, and benzene derivatives positively regulated dormancy breaking and sprouting in tubers of both yam genotypes. Metabolite set enrichment analysis (MSEA) revealed that 12 metabolisms were significantly enriched during yam tuber dormancy stages. Metabolic pathway topology analysis further revealed that six metabolic pathways (linoleic acid metabolic pathway, phenylalanine metabolic pathway, galactose metabolic pathway, starch and sucrose metabolic pathway, alanine-aspartate-glutamine metabolic pathways, and purine metabolic pathway) exerted significant impact on yam tuber dormancy regulation. This result provides vital insights into molecular mechanisms regulating yam tuber dormancy.

Keywords: antioxidant; differential–accumulation; dormancy; energy; metabolism; metabolites; molecular–mechanism; regulation.

Grants and funding

EACEA/2017/2552/EU; GENES Intra-Africa Academic Mobility Project; "Mobility for plant genomics scholars to acceler-ate climate-smart adaptation options and food security in Africa (GENES)" funded by European Union. GENES Intra-Africa Academic Mobility Project.