Alleviating effect of calcium sulfate on aluminum stress through enhanced malate release with increased gene expression of malate transporter and sulfate transporter

ABSTRACT

Gypsum (calcium sulfate) are commonly used to improve subsoil acidity. Aluminum (Al) toxicity in acid soil reduces crop yields worldwide, especially in the tropical regions. In soil, sulfate decrease Al toxicity and improves plant growth and yield. Here, we aimed to investigate the effects of CaSO₄ on Al stress of Al-tolerant accession Col-0 as well as the Al-sensitive accessions, Wei-0 and Ts-5, of in Arabidopsis thaliana using hydroponics. Our research indicates that CaSO₄ supply has a significant effect on root growth and malate release compared to CaCl₂ under Al stress, especially in Al-sensitive accessions. In response to Al stress, CaSO₄ supply enhanced the expression of malate transporter gene AtALMT1 and sulfate transporter gene SULTR3;5, which were regulated by the Al-resistant transcription factor STOP1. Furthermore, knockout lines of SULTR3;5 and SULTR2;1, which are involved in sulfate uptake and translocation, were more Al-sensitive than the wild type under Al stress without CaSO₄, and malate release was reduced with decreased AtALMT1 expression. In conclusion, one of the alleviative effects of gypsum application on Al rhizotoxicity is promoted by sulfate through organic acid release mechanism enhancing AtALMT1 expression, alongside the Ca²⁺ reduction Al³⁺ activity on the plasma membrane.

KEY WORDS:

• Aluminum stress
• AtALMT1
• malate
• sulfur
• SULTR3;5

Acknowledgments

We would like to thank Professor. Noren Singh Konjengbam in Central Agricultural University, Imphal and Editage (www.editage.com) for English editing. We also thank Dr. Takuo Enomoto in Gifu University for technical assistance. Arabidopsis seed stocks were kindly provided by Arabidopsis Biological Resource Center.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/00380768.2024.2334278

Additional information

Funding

This work was supported by JSPS KAKENHI Grant Number 22H02227, 21H02088 and 22H02229.