Metabolic profiling of drought tolerance: Revealing how citrus rootstocks modulate plant metabolism under varying water availability

• Published in: Environmental and experimental botany 2023-02, Vol.206, p.105169, Article 105169
• Main Authors: Silva, Simone F., Miranda, Marcela T., Cunha, Camila P., Domingues-Jr, Adilson P., Aricetti, Juliana A., Caldana, Camila, Machado, Eduardo C., Ribeiro, Rafael V.
• Format: Article
• Language: English
• Subjects: Abiotic stress; arginine; asparagine; auxins; Citrus aurantium var. chrysocarpa; Citrus limonia; Citrus sinensis; drought; drought tolerance; environmental factors; metabolism; metabolites; Metabolome; nitric oxide; Primary metabolites; Rangpur lime; rehydration; root growth; Root system; rootstocks; shikimic acid; sugars; water stress
• ISSN: 0098-8472; 1873-7307
• DOI: 10.1016/j.envexpbot.2022.105169

Water stress is a major environmental factor affecting Citrus spp. and Rangpur lime is a drought-tolerant rootstock used to enhance orange yield in rainfed orchards. Here, we combined morpho-physiological analyses with metabolic profiling of roots and leaves of Valencia orange scions grafted onto Rangpur lime, Swingle citrumelo or Sunki mandarin rootstocks under water deficit. Our aim was to present a comprehensive spatio-temporal evaluation of citrus responses to drought and highlight the metabolic adjustments associated with drought tolerance induced by Rangpur lime. Plant responses were evaluated during the initial phase of reduction in water availability, when water deficit was maximum and also after rehydration. Fifty-eight primary metabolites were modulated by water deficit, mainly amino acids, organic acids and sugars. Metabolic changes indicated adjustments related to osmotic, energetic and redox processes under low water availability, which were dependent on rootstock and varied between roots and leaves and along the experimental period. Rangpur lime prioritized root growth in the initial phase of water deficit, which was linked to less sugar accumulation, changes in nucleotide metabolism and downregulation in Shikimic acid pathway. After rehydration, the resume of shoot growth was associated with high accumulation of arginine and asparagine. The better performance of Rangpur lime seems to be associated with its high sensitivity of roots to changes in water availability and possible signaling compounds, such as auxin and nitric oxide, have been suggested. •Citrus rootstocks are known to modulate drought tolerance.•Osmotic, energetic and redox adjustments under water deficit were rootstock-dependent and varied between roots and leaves.•Root growth during the initial phase of water deficit was associated with downregulation in Shikimic acid pathway.•After rehydration, the resume of shoot growth was associated with high accumulation of arginine and asparagine.•Rangpur lime exhibited high sensitivity to changes in substrate moisture, and auxin and NO are likely involved in drought signaling.