Open AccessSelenium Inhibits Root Elongation by Repressing the Generation of Endogenous Hydrogen Sulfide in Brassica rapa
Author(s) -
Yi Chen,
Haizhen Mo,
Meiyu Zheng,
Ming Xian,
Zhongqiang Qi,
Youqin Li,
Liangbin Hu,
Jian Chen,
Lifei Yang
Publication year - 2014
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0110904
Subject(s) - endogeny , brassica rapa , reactive oxygen species , oxidative stress , glutathione , selenium , chemistry , sodium hydrosulfide , phytotoxicity , biochemistry , hydrogen sulfide , microbiology and biotechnology , biology , biophysics , botany , enzyme , sulfur , gene , organic chemistry
Selenium (Se) has been becoming an emerging pollutant causing severe phytotoxicity, which the biochemical mechanism is rarely known. Although hydrogen sulfide (H 2 S) has been suggested as an important exogenous regulator modulating plant physiological adaptions in response to heavy metal stress, whether and how the endogenous H 2 S regulates Se-induce phytotoxicity remains unclear. In this work, a self-developed specific fluorescent probe (WSP-1) was applied to track endogenous H 2 S in situ in the roots of Brassica rapa under Se(IV) stress. Se(IV)-induced root growth stunt was closely correlated with the inhibition of endogenous H 2 S generation in root tips. Se(IV) stress dampened the expression of most LCD and DCD homologues in the roots of B. rapa . By using various specific fluorescent probes for bio-imaging root tips in situ , we found that the increase in endogenous H 2 S by the application of H 2 S donor NaHS could significantly alleviate Se(IV)-induced reactive oxygen species (ROS) over-accumulation, oxidative impairment, and cell death in root tips, which further resulted in the recovery of root growth under Se(IV) stress. However, dampening the endogenous H 2 S could block the alleviated effect of NaHS on Se(IV)-induced phytotoxicity. Finally, the increase in endogenous H 2 S resulted in the enhancement of glutathione (GSH) in Se(IV)-treated roots, which may share the similar molecular mechanism for the dominant role of H 2 S in removing ROS by activating GSH biosynthesis in mammals. Altogether, these data provide the first direct evidences confirming the pivotal role of endogenous H 2 S in modulating Se(IV)-induced phytotoxicity in roots.