3′‐UTR Hypermethylation and ABA Signaling Coordinate Transcriptional Activation of SWEET14 for High Sugar Accumulation in Citrus
4 affiliations
- 1National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops College of Horticulture and Forestry Sciences Huazhong Agricultural University Wuhan Hubei China
- 2State Key Laboratory of Woody Oil Resources Utilization, Key Laboratory of Cultivation and Protection for Non‐Wood Forest Trees of the Ministry of Education Central South University of Forestry and Technology Changsha Hunan China
- 3School of Horticulture Anhui Agricultural University Hefei Anhui China
- 4Hubei Hongshan Laboratory Wuhan Hubei China
Abstract
Sugar accumulation is pivotal for fruit quality, yet the molecular regulation of this process remains elusive. By comparing transcriptomes of sweet lemon (Citrus limon, SL, high sugar level) and Eureka (EL, trace amount of sugar), we identified the sucrose transporter CliSWEET14 as a key driver of sugar accumulation. Methylome atlas showed that the 26‐bp sequence within 3′‐untranslated region (UTR) of CliSWEET14‐SL was substantially hypermethylated relative to CliSWEET14‐EL. Notably, the 3′‐UTRs of both genes formed chromatin loops with their native promoters. ClibHLH105 bound to unmethylated CACGAT sequence in the loop and repressed CliSWEET14‐EL. In contrast, hypermethylation of the CACGAT motif disrupted ClibHLH105 interaction and repression on CliSWEET14‐SL. Additionally, CliSWEET14‐SL was positively regulated by CliNAC56, which was further activated by CliABF3. Both CliNAC56 and CliABF3 regulated sucrose accumulation in a CliSWEET14‐dependent manner. Moreover, the regulatory cascade CliABF3‐CliNAC56‐CliSWEET14 in SL was activated by ABA (abscisic acid) to a greater degree due to higher ABA level. Taken together, 3′‐UTR hypermethylation‐mediated relief of transcriptional repression and stronger activation by ABA signaling robustly boost CliSWEET14 expression and sucrose accumulation. These findings substantially advance our understanding of sugar accumulation in fruit and provide novel epigenetic and transcriptional targets for improving fruit quality in citrus and beyond.
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BibTeX
@article{zeng20263utr,
title = {{3′‐UTR Hypermethylation and ABA Signaling Coordinate Transcriptional Activation of SWEET14 for High Sugar Accumulation in Citrus}},
author = {Yike Zeng and Yue Wang and Yilei Wang and Haowei Chen and Qiyu Chen and Wei Xiao and Aoqing Zhang and Xin Jiang and Xiangming Shang and Zhicheng Yang and Xi Zeng and Wenqiang Hu and Chunlong Li and Ji‐Hong Liu},
journal = {Advanced Science},
year = {2026},
month = oct,
doi = {10.1002/advs.78518},
url = {https://doi.org/10.1002/advs.78518},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - 3′‐UTR Hypermethylation and ABA Signaling Coordinate Transcriptional Activation of SWEET14 for High Sugar Accumulation in Citrus
AU - Yike Zeng
AU - Yue Wang
AU - Yilei Wang
AU - Haowei Chen
AU - Qiyu Chen
AU - Wei Xiao
AU - Aoqing Zhang
AU - Xin Jiang
AU - Xiangming Shang
AU - Zhicheng Yang
AU - Xi Zeng
AU - Wenqiang Hu
AU - Chunlong Li
AU - Ji‐Hong Liu
PY - 2026
DA - 2026/10/31
JO - Advanced Science
DO - 10.1002/advs.78518
UR - https://doi.org/10.1002/advs.78518
AB - Sugar accumulation is pivotal for fruit quality, yet the molecular regulation of this process remains elusive. By comparing transcriptomes of sweet lemon (Citrus limon, SL, high sugar level) and Eureka (EL, trace amount of sugar), we identified the sucrose transporter CliSWEET14 as a key driver of sugar accumulation. Methylome atlas showed that the 26‐bp sequence within 3′‐untranslated region (UTR) of CliSWEET14‐SL was substantially hypermethylated relative to CliSWEET14‐EL. Notably, the 3′‐UTRs of both genes formed chromatin loops with their native promoters. ClibHLH105 bound to unmethylated CACGAT sequence in the loop and repressed CliSWEET14‐EL. In contrast, hypermethylation of the CACGAT motif disrupted ClibHLH105 interaction and repression on CliSWEET14‐SL. Additionally, CliSWEET14‐SL was positively regulated by CliNAC56, which was further activated by CliABF3. Both CliNAC56 and CliABF3 regulated sucrose accumulation in a CliSWEET14‐dependent manner. Moreover, the regulatory cascade CliABF3‐CliNAC56‐CliSWEET14 in SL was activated by ABA (abscisic acid) to a greater degree due to higher ABA level. Taken together, 3′‐UTR hypermethylation‐mediated relief of transcriptional repression and stronger activation by ABA signaling robustly boost CliSWEET14 expression and sucrose accumulation. These findings substantially advance our understanding of sugar accumulation in fruit and provide novel epigenetic and transcriptional targets for improving fruit quality in citrus and beyond.
SN - 2198-3844
ER -