Uncovering differences in cadmium accumulation capacity of different Ipomoea aquatica cultivars at the level of root cell types

Abstract

Water spinach (Ipomoea aquatica) can accumulate cadmium (Cd) even in mildly contaminated soils, but the roles of its root tip cell types in Cd fixation and transport remain unclear. Single-cell RNA sequencing revealed nine cell types in root tips in both the QLQ cultivar (low Cd accumulation) and the T308 cultivar (high Cd accumulation). High expression of LAC2 and PER72 in the QLQ epidermis was associated with enhanced lignin deposition, which may facilitate fixation of Cd and reduce its translocation to the shoot. In T308, PER72 and hormone-related genes (PIN1, ARF8, IAA17, and EIN3) were upregulated, which was hypothesized to promote xylem and trichoblast development, potentially facilitating Cd uptake and transport. Fluorescence assays suggested that the higher pectin demethylation and lignin content in QLQ may limit Cd movement, whereas the more developed tissues in T308 may contribute to increased Cd accumulation in the shoots. These findings clarify the mechanisms by which Cd accumulates in water spinach and offer insights into mitigating Cd uptake in crops.

Acknowledgments

This study was supported by the National Natural Science Foundation of China (Grant No. 42107039 and 42007144), Natural Science Foundation of Hunan Province, China (Grant No. 2022JJ40139), Scientific Research Foundation of Hunan Provincial Education Department (Grant No. 24B0838) and College Students Research Learning and Innovative Experiment Project of Hunan Province (Grant No. S202311528145). In addition, I would like to express my deepest gratitude to Mr. Chen (B) and Mr. Zhang (Pao) for their consistent provision of nutritional support and wellness resources throughout this research. Their contributions significantly alleviated physical challenges during intensive study periods, enabling sustained focus on this work. May this collaborative spirit inspire continued growth within our scholarly community.

Author Contributions

A total of six authors participated in this work, including Chuang Shen, Bai-Fei Huang, Qiong Liao, Kai-Feng Chen, Jun-Liang Xin, and Ying-Ying Huang. Conception and design of study: Chuang Shen and Ying-Ying Huang. Acquisition of data: Chuang Shen, Bai-Fei Huang, Qiong Liao, Kai-Feng Chen, Jun-Liang Xin. Analysis and/or interpretation of data: Chuang Shen, Bai-Fei Huang, Ying-Ying Huang. Drafting the manuscript: Chuang Shen and Bai-Fei Huang. Revising the manuscript critically for important intellectual content: Chuang Shen and Ying-Ying Huang.

Data availability

The raw scRNA-seq data from this study have been deposited in the China National Center for Bioinformation under BioProject ID: PRJCA029540. Similarly, the raw bulk RNA-seq data are available in the same repository under BioProject ID: PRJCA029575.

Conflict of interest statement:

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Supplementary data

Supplementary data is available at Horticulture Research online.

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