Effects of aluminum (Al) stress on the isoprenoid metabolism of two Citrus species differing in Al-tolerance

Ecotoxicol Environ Saf. 2024 Jul 15:280:116545. doi: 10.1016/j.ecoenv.2024.116545. Epub 2024 Jun 7.

Abstract

Isoprenoid metabolism and its derivatives took part in photosynthesis, growth regulation, signal transduction, and plant defense to biotic and abiotic stresses. However, how aluminum (Al) stress affects the isoprenoid metabolism and whether isoprenoid metabolism plays a vital role in the Citrus plants in coping with Al stress remain unclear. In this study, we reported that Al-treatment-induced alternation in the volatilization rate of monoterpenes (α-pinene, β-pinene, limonene, α-terpinene, γ-terpinene and 3-carene) and isoprene were different between Citrus sinensis (Al-tolerant) and C. grandis (Al-sensitive) leaves. The Al-induced decrease of CO2 assimilation, maximum quantum yield of primary PSII photochemistry (Fv/Fm), the lower contents of glucose and starch, and the lowered activities of enzymes involved in the mevalonic acid (MVA) pathway and 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway might account for the different volatilization rate of isoprenoids. Furthermore, the altered transcript levels of genes related to isoprenoid precursors and/or derivatives metabolism, such as geranyl diphosphate (GPP) synthase (GPPS) in GPP biosynthesis, geranylgeranyl diphosphate synthase (GGPPS), chlorophyll synthase (CHS) and GGPP reductase (GGPPR) in chlorophyll biosynthesis, limonene synthase (LS) and α-pinene synthase (APS) in limonene and α-pinene synthesis, respectively, might be responsible for the different contents of corresponding products in C. grandis and C. sinensis. Our data suggested that isoprenoid metabolism was involved in Al tolerance response in Citrus, and the alternation of some branches of isoprenoid metabolism could confer different Al-tolerance to Citrus species.

Keywords: Aluminum toxicity; Carotenoids; Citrus; Isoprene; Isoprenoid metabolism.

MeSH terms

  • Alkyl and Aryl Transferases / genetics
  • Alkyl and Aryl Transferases / metabolism
  • Aluminum* / toxicity
  • Bicyclic Monoterpenes* / metabolism
  • Butadienes / metabolism
  • Chlorophyll / metabolism
  • Citrus sinensis / drug effects
  • Citrus sinensis / genetics
  • Citrus sinensis / metabolism
  • Citrus* / drug effects
  • Citrus* / metabolism
  • Cyclohexane Monoterpenes
  • Cyclohexenes / metabolism
  • Erythritol / analogs & derivatives
  • Erythritol / metabolism
  • Hemiterpenes / metabolism
  • Limonene* / metabolism
  • Mevalonic Acid / metabolism
  • Monoterpenes / metabolism
  • Photosynthesis* / drug effects
  • Plant Leaves* / drug effects
  • Plant Leaves* / metabolism
  • Stress, Physiological / drug effects
  • Sugar Phosphates / metabolism
  • Terpenes* / metabolism
  • Volatilization

Substances

  • Aluminum
  • Terpenes
  • Limonene
  • Bicyclic Monoterpenes
  • Monoterpenes
  • alpha-pinene
  • isoprene
  • 2-C-methylerythritol 4-phosphate
  • Hemiterpenes
  • Cyclohexenes
  • Sugar Phosphates
  • Butadienes
  • Erythritol
  • beta-pinene
  • gamma-terpinene
  • 3-carene
  • Mevalonic Acid
  • Cyclohexane Monoterpenes
  • Chlorophyll
  • Alkyl and Aryl Transferases