Dataset Information

Rootstock influence on iron uptake responses in Citrus leaves and their regulation under the Fe paradox effect.

ABSTRACT:

Background and aims

This work evaluates the regulation of iron uptake responses in Citrus leaves and their involvement in the Fe paradox effect.

Methods

Experiments were performed in field-grown 'Navelina' trees grafted onto two Cleopatra mandarin × Poncirus trifoliata (L.) Raf. hybrids with different Fe-chlorosis symptoms: 030146 (non-chlorotic) and 030122 (chlorotic).

Results

Chlorotic leaves were smaller than non-chlorotic ones for both dry weight (DW) and area basis, and exhibited marked photosynthetic state affection, but reduced catalase and peroxidase enzymatic activities. Although both samples had a similar total Fe concentration on DW, it was lower in chlorotic leaves when expressed on an area basis. A similar pattern was observed for the total Fe concentration in the apoplast and cell sap and in active Fe (Fe²⁺) concentration. FRO2 gene expression and ferric chelate reductase (FC-R) activity were also lower in chlorotic samples, while HA1 and IRT1 were more induced. Despite similar apoplasmic pH, K⁺/Ca²⁺ was higher in chlorotic leaves, and both citrate and malate concentrations in total tissue and apoplast fluid were lower.

Conclusion

(1) The rootstock influences Fe acquisition system in the leaf; (2) the increased sensitivity to Fe-deficiency as revealed by chlorosis and decreased biomass, was correlated with lower FC-R activity and lower organic acid level in leaf cells, which could cause a decreased Fe mobility and trigger other Fe-stress responses in this organ to enhance acidification and Fe uptake inside cells; and (3) the chlorosis paradox phenomenon in citrus likely occurs as a combination of a marked FC-R activity impairment in the leaf and the strong growth inhibition in this organ.

SUBMITTER: Martinez-Cuenca MR

PROVIDER: S-EPMC5619235 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Rootstock influence on iron uptake responses in <i>Citrus</i> leaves and their regulation under the Fe paradox effect.

Martinez-Cuenca Mary-Rus MR Primo-Capella Amparo A Quiñones Ana A Bermejo Almudena A Forner-Giner Maria Angeles MA

PeerJ 20170925

<h4>Background and aims</h4>This work evaluates the regulation of iron uptake responses in Citrus leaves and their involvement in the Fe paradox effect.<h4>Methods</h4>Experiments were performed in field-grown 'Navelina' trees grafted onto two Cleopatra mandarin × <i>Poncirus trifoliata</i> (L.) Raf. hybrids with different Fe-chlorosis symptoms: 030146 (non-chlorotic) and 030122 (chlorotic).<h4>Results</h4>Chlorotic leaves were smaller than non-chlorotic ones for both dry weight (DW) and area ba ...[more]

PMID: 28966887

Similar Datasets

Project description:Iron is an essential micronutrient for plants, and plants have evolved adaptive mechanisms to improve iron acquisition from soils. Grafting on iron deficiency-tolerant rootstock is an effective strategy to prevent iron deficiency-chlorosis in fruit-tree crops. To determine the mechanisms underlying iron uptake in iron deficiency, two iron deficiency-tolerant citrus rootstocks, Zhique (ZQ) and Xiangcheng (XC), as well as iron deficiency-sensitive rootstock trifoliate orange (TO) seedlings were studied. Plants were grown in hydroponics system for 100 days, having 50 μM iron (control) and 0 μM iron (iron deficiency) nutrient solution. Under iron deficiency, more obvious visual symptoms of iron chlorosis were observed in the leaves of TO, whereas slight symptoms were observed in ZQ and XC. This was further supported by the lower chlorophyll concentration in the leaves of TO than in leaves of ZQ and XC. Ferrous iron showed no differences among the three citrus rootstock roots, whereas ferrous iron was significantly higher in leaves of ZQ and XC than TO. The specific iron absorption rate and leaf iron proportion were significantly higher in ZQ and XC than in TO, suggesting the iron deficiency tolerance can be explained by increased iron uptake in roots of ZQ and XC, allowed by subsequent translocation to shoots. In transcriptome analysis, 29, 298, and 500 differentially expressed genes (DEGs) in response to iron deficiency were identified in ZQ, XC, and TO, respectively (Fold change ≥ 2 and Probability ≥ 0.8 were used as thresholds to identify DEGs). A Gene Ontology analysis suggested that several genotype-specific biological processes are involved in response to iron deficiency. Genes associated with cell wall biosynthesis, ethylene and abscisic acid signal transduction pathways were involved in iron deficiency responses in citrus rootstocks. The results of this study provide a basis for future analyses of the physiological and molecular mechanisms of the tolerance of different citrus rootstocks to iron deficiency.