Shoot-to-root mobile CEPD-like 2 integrates shoot nitrogen status to systemically regulate nitrate uptake in Arabidopsis
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ABSTRACT: Plants modulate the efficiency of root nitrogen (N) acquisition in response to shoot N demand. However, molecular components directly involved in this shoot-to-root communication remain to be identified. Here, we show that phloem-mobile CEPD-like 2 (CEPDL2) polypeptide is upregulated in the leaf vasculature in response to decreased shoot N status and, after translocation to the roots, promotes high-affinity uptake and root-to-shoot transport of nitrate by activating nitrate transporter genes such as NRT2.1, NRT3.1 and NRT1.5. Loss of CEPDL2 decreases nitrate uptake and root-to-shoot transport activity in roots, leading to a reduction in shoot nitrate content and plant biomass. CEPDL2 contributes to N acquisition cooperatively with CEPD1 and CEPD2 that mediate root N status, and their complete loss severely impairs N homeostasis in plants. Reciprocal grafting analysis provided conclusive evidence that the shoot CEPDL2/CEPD genotype defines the root high-affinity uptake activity of nitrate. Our results indicate that plants integrate shoot N status and root N status in leaves and systemically regulate the efficiency of root N acquisition.
ORGANISM(S): Arabidopsis thaliana
PROVIDER: GSE140834 | GEO | 2020/02/10
REPOSITORIES: GEO
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