Uncovering metabolite changes in rice leaves (Oryza sativa L.) during vegetative stages using ethanolic extract analysis based on gas chromatography-mass spectrometry

Abstract

Importance of the work: This research contributes to understanding rice physiology and
emphasizes the potential for utilizing metabolomic data in breeding programs aimed at enhancing
crop resilience and yield.
Objectives: To investigate the metabolite profiles of rice leaves and to elucidate the catabolic
pathway of chlorophyll during critical growth stages.
Materials and Methods: Two rice varieties, IR50404 (IR504) and Huyet Rong (HRO), were
examined at 3 wk and 5 wk of growth to elucidate the changes in key metabolites using gas
chromatography-mass spectrometry analysis. The total chlorophyll contents of rice leaves were
measured to determine the shift in metabolite pathways.
Results: There were significant differences in the chlorophyll content, with both varieties having
higher levels at 3 wk than at 5 wk. The profiling revealed that IR504 contained a greater number
of metabolites than HRO at both time points. Notably, phytol and bis(2-ethylhexyl) phthalate
(DEHP) were predominant compounds, with the phytol levels notably increasing in HRO by week
5. Additionally, there were metabolic shifts in the volatile organic compounds, with an increase
in diterpenoids and a decrease in phthalate esters as the plants matured. Based on the results, the
study proposed the metabolic pathway of chlorophyll degradation to produce important compounds
(phytol, vitamin E and fatty acid derivatives) in rice leaves.
Main finding: Overall, the findings underscored the dynamic nature of rice leaf metabolism and
provided insights into the biochemical adaptations that occur during critical growth stages.