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Regulation on copper-tolerance in Citrus sinensis seedlings by boron addition: Insights from root exudates, related metabolism, and gene expression.
- Source :
-
Journal of Hazardous Materials . Oct2023, Vol. 459, pN.PAG-N.PAG. 1p. - Publication Year :
- 2023
-
Abstract
- Boron (B) can alleviate Citrus copper (Cu)-toxicity. However, the underlying mechanism by which B mitigates Cu-toxicity is unclear. 'Xuegan' (Citrus sinensis) seedlings were exposed to 0.5 (control) or 350 (Cu-toxicity) µM Cu and 2.5 or 25 µM B for 24 weeks. Thereafter, we investigated the secretion of low molecular weight compounds [LMWCs; citrate, malate, total soluble sugars (TSS), total phenolics (TP), and total free amino acids (TFAA)] by excised roots and their concentrations in roots and leaves, as well as related enzyme gene expression and activities in roots and leaves. Cu-stress stimulated root release of malate and TFAA, which might contribute to citrus Cu-tolerance. However, B-mediated-mitigation of Cu-stress could not be explained in this way, since B addition failed to further stimulate malate and TFAA secretion. Indeed, B addition decreased Cu-stimulated-secretion of malate. Further analysis suggested that Cu-induced-exudation of malate and TFAA was not regulated by their levels in roots. By contrast, B addition increased malate, citrate, and TFAA concentrations in Cu-toxic roots. Cu-toxicity increased TP concentration in 25 μM B-treated leaves, but not in 2.5 μM B-treated leaves. Our findings suggested that the internal detoxification of Cu by LMWCs played a role in B-mediated-alleviation of Cu-toxicity. [Display omitted] • Root secretion of malate and amino acids plays a vital role in Citrus Cu-tolerance. • Secretion of malate and amino acids was not regulated by their levels in roots. • Internal detoxification of Cu plays a role in B-mediated-mitigation of Cu-toxicity. • LWMC metabolism responses to Cu and B treatments differed between leaves and roots. [ABSTRACT FROM AUTHOR]
- Subjects :
- *PLANT exudates
*GENE expression
*MOLECULES
*COPPER
*BORON
*ORANGES
Subjects
Details
- Language :
- English
- ISSN :
- 03043894
- Volume :
- 459
- Database :
- Academic Search Index
- Journal :
- Journal of Hazardous Materials
- Publication Type :
- Academic Journal
- Accession number :
- 170720915
- Full Text :
- https://doi.org/10.1016/j.jhazmat.2023.132277