Phenylmercury stress induces root tip swelling through auxin homeostasis disruption.

Autor: Uraguchi S; Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan. uraguchis@pharm.kitasato-u.ac.jp., Sato M; Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan., Hagai C; Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan., Hirakawa M; Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan., Ogawa K; Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan., Odagiri M; Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan., Sato H; Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan., Ohmori A; Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan., Ohshiro Y; Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan., Nakamura R; Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan., Takanezawa Y; Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan., Kiyono M; Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan. kiyonom@pharm.kitasato-u.ac.jp.
Jazyk: angličtina
Zdroj: Plant molecular biology [Plant Mol Biol] 2024 Dec 18; Vol. 115 (1), pp. 8. Date of Electronic Publication: 2024 Dec 18.
DOI: 10.1007/s11103-024-01538-6
Abstrakt: We previously reported that in Arabidopsis, the phytochelatin-mediated metal-detoxification machinery is also essential for organomercurial phenylmercury (PheHg) tolerance. PheHg treatment causes severe root growth inhibition in cad1-3, an Arabidopsis phytochelatin-deficient mutant, frequently accompanied by abnormal root tip swelling. Here, we examine morphological and physiological characteristics of PheHg-induced abnormal root tip swelling in comparison to Hg(II) stress and demonstrate that auxin homeostasis disorder in the root is associated with the PheHg-induced root tip swelling. Both Hg(II) and PheHg treatments severely inhibited root growth in cad1-3 and simultaneously induced the disappearance of starch-containing plastid amyloplasts in columella cells. However, further confocal imaging of the root tip revealed distinct effects of Hg(II) and PheHg toxicity on root cell morphology. PheHg treatment suppressed most major genes involved in auxin homeostasis, whereas these expression levels were up-regulated after 24 h of Hg(II) treatment. PheHg-triggered suppression of auxin transporters PIN1, PIN2, and PIN3 as GFP-fusion proteins was observed in the root tip, accompanied by an auxin reporter DR5rev::GFP signal reduction. Supplementation of indole-3-acetic acid (IAA) drastically canceled the PheHg-induced root swelling, however, Hg(II) toxicity was not mitigated by IAA. The presented results show that the collapse of auxin homeostasis especially in root tips is a cause for the abnormal root tip swelling under PheHg stress conditions.
Competing Interests: Declarations. Conflict of interest: The authors declare no conflicts of interest.
(© 2024. The Author(s).)
Databáze: MEDLINE
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