title: Effects of hydrogen sulfide on alternative pathway respiration and induction of alternative oxidase gene expression in rice suspension cells.
abstract: The toxic effects of H2S on plants are well documented. However, the molecular mechanisms reponsible for inhibition of plants by H2S are still not completely understood. We determined the effects of NaHS in the range of 0.5-10 mM on the growth of rice suspension culture cells, as well as on the expression of the alternative oxidase (AOX) gene. AOX is the terminal oxidase of the alternative pathway (AP) and exists in plant mitochondria. The results showed that H2S treatment enhanced the AP activity. During the process of H2S treatment for 4 h, the AP activity increased dramatically and achieved the peak value at a concentration of 2 mM NaHS. Then it declined at higher concentrations of NaHS (5-10 mM) and maintained a steady level. The AOX1 gene transcript level also showed a similar change as the AP activity. Interestingly, different NaHS concentrations seemed to have different effects on the expression of AOX1a, AOX1b, and AOX1c. The induction of AOX expression by low concentrations of NaHS was inferred through a reactive oxygen species (ROS)-independent pathway. At the same time, rice cells grown in culture were very sensitive to H2S, different H2S concentrations induced an increase in the cell viability. These results indicate that the H2S-induced AOX induction might play a role in inhibiting the ROS production and have an influence on cell viability.
authors.affiliation: MOE Key Laboratory of Arid and Grassland Ecology, School of Life Sciences, Lanzhou University, 298 Tian Shui Road, Lanzhou 730000, PR China. xiaoman-shen@hotmail.com
authors.forename: Man
authors.initials: M
authors.lastname: Xiao
authors.forename: Jun
authors.initials: J
authors.lastname: Ma
authors.forename: Hongyu
authors.initials: H
authors.lastname: Li
authors.forename: Han
authors.initials: H
authors.lastname: Jin
authors.forename: Hanqing
authors.initials: H
authors.lastname: Feng
mesh_terms: D019069:Cell Respiration / Q000235:genetics; D017931:DNA Primers; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D006861:Hydrogen Peroxide / Q000378:metabolism; D006862:Hydrogen Sulfide / Q000494:pharmacology*; D024101:Mitochondrial Proteins; D012275:Oryza / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism; D010088:Oxidoreductases / Q000235:genetics* / Q000378:metabolism; D010940:Plant Proteins; D018749:RNA, Plant / Q000235:genetics / Q000302:isolation & purification; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000099188:Alternative Oxidase
chemical_list: D017931:DNA Primers; D006861:Hydrogen Peroxide; D006862:Hydrogen Sulfide; D024101:Mitochondrial Proteins; D010088:Oxidoreductases; D010940:Plant Proteins; D018749:RNA, Plant; D000099188:Alternative Oxidase