Long-distance transport of sucrose in source leaves promotes sink root growth by the EIN3-SUC2 module

In most plants, sucrose, a major storage sugar, is transported into sink organs to support their growth. This key physiological process is dependent on the function of sucrose transporters. Sucrose export from source tissues is predominantly controlled through the activity of SUCROSE TRANSPORTER 2 (...

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Bibliographic Details
Published in:PLoS genetics 2022-09, Vol.18 (9), p.e1010424-e1010424
Main Authors: Tong, Chen, Li, Cong, Cao, Xiao-Ying, Sun, Xu-Dong, Bao, Qin-Xin, Mu, Xin-Rong, Liu, Chang-Yue, Loake, Gary J, Chen, Hu-hui, Meng, Lai-Sheng
Format: Article
Language:English
Subjects:
Analysis
Arabidopsis thaliana
Binding sites
Biology and Life Sciences
Ethylene
Glucose
Growth
Hexokinase
Phloem
Physical Sciences
Plant growth
Research and Analysis Methods
Roots (Botany)
Sensors
Sucrose
Sucrose transporter
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Summary:In most plants, sucrose, a major storage sugar, is transported into sink organs to support their growth. This key physiological process is dependent on the function of sucrose transporters. Sucrose export from source tissues is predominantly controlled through the activity of SUCROSE TRANSPORTER 2 (SUC2), required for the loading of sucrose into the phloem of Arabidopsis plants. However, how SUC2 activity is controlled to support root growth remains unclear. Glucose is perceived via the function of HEXOKINASE 1 (HXK1), the only known nuclear glucose sensor. HXK1 negatively regulates the stability of ETHYLENE-INSENSITIVE3 (EIN3), a key ethylene/glucose interaction component. Here we show that HXK1 functions upstream of EIN3 in the regulation of root sink growth mediated by glucose signaling. Furthermore, the transcription factor EIN3 directly inhibits SUC2 activity by binding to the SUC2 promoter, regulating glucose signaling linked to root sink growth. We demonstrate that these molecular components form a HXK1-EIN3-SUC2 module integral to the control of root sink growth. Also, we demonstrate that with increasing age, the HXK1-EIN3-SUC2 module promotes sucrose phloem loading in source tissues thereby elevating sucrose levels in sink roots. As a result, glucose signaling mediated-sink root growth is facilitated. Our findings thus establish a direct molecular link between the HXK1-EIN3-SUC2 module, the source-to sink transport of sucrose and root growth.
ISSN:1553-7404
1553-7390
1553-7404
DOI:10.1371/journal.pgen.1010424