Exogenous riboflavin (vitamin B2) application enhances salinity tolerance through the activation of its biosynthesis in rice seedlings under salinity stress

Jiadkong Kamonthip

Fauzia Anisa Nazera

Yamaguchi Nobuo

Ueda Akihiro

Plant Science

Salinity stress triggers the accumulation of reactive oxygen species (ROS), leading to impaired plant growth. Riboflavin (RIB; vitamin B2) is synthesized by plants, fungi, and microorganisms and is a precursor of the coenzymes, flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN), which are important for cellular metabolism. In this study, we aimed to elucidate the mechanistic basis of the RIB-mediated alleviation of salinity stress in rice. We observed higher biomass accumulation and lower concentrations of malondialdehyde (MDA) and hydrogen peroxide (H2O2) in RIB-pretreated seedlings under salinity stress. In vitro assays showed that H2O2 was scavenged as the RIB concentration increased, implying that RIB may function as a non-enzymatic antioxidant in ROS detoxification. RIB-pretreated seedlings accumulated more Na+ in the roots than in the leaf blades because of the contributions of OsHKT2;1, OsNHX1, and OsHKT1;4 in the roots and leaf sheaths, respectively. Liquid chromatography-mass spectrometry (LC-MS/MS) analysis revealed increased RIB concentration in roots and shoots and upregulation of key genes (OsRIBA1, OsGCHI, OsLS, and OsRS) involved in RIB biosynthesis in the roots of RIB-pretreated seedlings. Taken together, our findings suggest that RIB pretreatment ameliorates salinity stress in rice by improving (1) oxidative stress tolerance, as increased RIB concentration may function as a non-enzymatic antioxidant, and (2) ionic stress tolerance, as RIB pretreatment limits Na+ accumulation in the leaf blades and maintains a favorable Na+/K+ balance.

Riboflavin biosynthesis

Root priming

ROS scavenger

Non-enzymatic antioxidant

DEGs

eng

Elsevier

© 2023. This manuscript version is made available under the CC-BY-NC-ND 4.0 license https://creativecommons.org/licenses/by-nc-nd/4.0/

This is not the published version. Please cite only the published version.

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[DOI] https://doi.org/10.1016/j.plantsci.2023.111929 isVersionOf

日本学術振興会

Japan Society for the Promotion of Science

[Crossref Funder] https://doi.org/10.13039/501100001691

タイの塩・アルカリ水田で栽培可能な耐性イネ系統の創出 Research Project

タイの塩・アルカリ水田で栽培可能な耐性イネ系統の創出 Research Project

20KK0129