Phloem unloading via the apoplastic pathway is essential for shoot distribution of root-synthesized cytokinins
[1];
[1];
[1];
[1];
[1];
[1];
[1];
[2];
[2];
[3];
[4];
[1]
- Institute of Plant Genetics and Developmental Biology, Zhejiang Provincial Key Laboratory of Biotechnology on Specialty Economic Plants, College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, Zhejiang 321004, P.R. China
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, P.R. China
- Department of Agronomy and Purdue Center for Plant Biology, Purdue University, West Lafayette, Indiana, USA
- Biology Department, Brookhaven National Laboratory, Upton, New York 11973, USA
Abstract Root-synthesized cytokinins are transported to the shoot and regulate the growth, development, and stress responses of aerial tissues. Previous studies have demonstrated that Arabidopsis (Arabidopsis thaliana) ATP binding cassette (ABC) transporter G family member 14 (AtABCG14) participates in xylem loading of root-synthesized cytokinins. However, the mechanism by which these root-derived cytokinins are distributed in the shoot remains unclear. Here, we revealed that AtABCG14-mediated phloem unloading through the apoplastic pathway is required for the appropriate shoot distribution of root-synthesized cytokinins in Arabidopsis. Wild-type rootstocks grafted to atabcg14 scions successfully restored trans-zeatin xylem loading. However, only low levels of root-synthesized cytokinins and induced shoot signaling were rescued. Reciprocal grafting and tissue-specific genetic complementation demonstrated that AtABCG14 disruption in the shoot considerably increased the retention of root-synthesized cytokinins in the phloem and substantially impaired their distribution in the leaf apoplast. The translocation of root-synthesized cytokinins from the xylem to the phloem and the subsequent unloading from the phloem is required for the shoot distribution and long-distance shootward transport of root-synthesized cytokinins. This study revealed a mechanism by which the phloem regulates systemic signaling of xylem-mediated transport of root-synthesized cytokinins from the root to the shoot.
- Research Organization:
- Brookhaven National Laboratory (BNL), Upton, NY (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences & Biosciences Division
- Grant/Contract Number:
- SC0012704
- OSTI ID:
- 1811733
- Alternate ID(s):
- OSTI ID: 1806353; OSTI ID: 1828312
- Report Number(s):
- BNL-222332-2021-JAAM
- Journal Information:
- Plant Physiology (Bethesda), Journal Name: Plant Physiology (Bethesda) Vol. 186 Journal Issue: 4; ISSN 0032-0889
- Publisher:
- Oxford University PressCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Similar Records
Changes in iron availability in Arabidopsis are rapidly sensed in the leaf vasculature and impaired sensing leads to opposite transcriptional programs in leaves and roots
Phloem loading in Coleus blumei in the absence of carrier-mediated uptake of export sugar from the apoplast. [Coleus blumei Benth]