H_(2)S信号在拟南芥响应SO_(2)胁迫过程中的作用

Functions of H_(2)S signal in response to SO_(2) stress in Arabidopsis thaliana

以拟南芥为实验材料,研究植物对H_(2)S和SO_(2)处理的转录响应及其关系,并利用外源喷施H_(2)S及其清除剂的方法,检测SO_(2)熏气后植株体内H_(2)S的产生及其生理效应,探讨气体信号分子H_(2)S在植物响应SO_(2)胁迫过程中的作用.高通量测序结果发现,H_(2)S和SO_(2)处理诱导拟南芥植株多个基因转录水平改变,并有1220个基因在两种处理条件下均差异表达,其中包括多个硫代谢和谷胱甘肽代谢相关基因,表明H_(2)S和SO_(2)在调控硫代谢途径中具有交互作用.SO_(2)熏气诱导拟南芥植株体内H_(2)S合成酶基因LCD和DES1转录水平提高,胞内H_(2)S含量增多.同时,超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性升高,含硫抗氧化物谷胱甘肽(GSH)含量及其相关酶谷胱甘肽硫转移酶(GST)和谷胱甘肽过氧化物酶(GPX)活性提高,活性氧H_(2)O_(2)含量增加,膜脂过氧化产物丙二醛(MDA)含量与对照相比无显著差异.外源喷施H_(2)S可进一步提高SO_(2)熏气下拟南芥植株GSH含量及其相关防御酶的活性,H_(2)O_(2)含量降低.但喷施亚牛磺酸(HT)清除H_(2)S后,SO_(2)熏气拟南芥植株GSH含量、抗氧化酶SOD、CAT和GST活性降低,MDA含量大幅增加.结果表明,SO_(2)熏气诱导产生的H_(2)S可作为信号分子,提高机体抗氧化防御能力,增强植物对SO_(2)胁迫的抗性.

Sulfur dioxide(SO_(2))is one of the most common and harmful air pollutant.Hydrogen sulfide(H_(2)S),as a new gasotransmitter,is involved in the regulation of plant development and stress adaptation.To reveal the role of H_(2)S in response to SO_(2)stress,the relation between transcriptional response to H_(2)S and SO_(2)treatments,and the production and physiological effect of H_(2)S during SO_(2)fumigation will be studied in Arabidopsis plants.By using high-throughput sequencing,many genes were identified to be differentially expressed in Arabidopsis plants exposed to 30mg/m3 SO_(2)or treated with 0.1mmol/L H_(2)S.Among these differentially expressed genes(DEGs),122,0genes were overlapped between SO_(2)and H_(2)S treatments,including some genes encoding enzymes involved in sulfur and glutathione metabolism.These results suggested a interaction between H_(2)S and SO_(2)in regulating sulfur metabolism pathways in plants.Moreover,two H_(2)S-generating genes,L-cysteine desulfhydrase(LCD)and L-cysteinedesulfhydrase1(DES1)were significantly up-regulated,and endogenous H_(2)S content was enhanced in Arabidopsis plants under SO_(2)stress.Meanwhile,the activities of superoxide dismutase(SOD)and catalase(CAT),the content of glutathione(GSH)and activities of GSH-related enzymes including glutathione S-transferase(GST)and glutathione peroxidase(GPX)were significantly increased in Arabidopsis plants exposed to SO_(2).And that H2O2 content was markedly increased in SO_(2)-treated Arabidopsis plants,while malondialdehyde(MDA)content showed no significant difference compared with the control group.Exogenous application of H_(2)S further increased the level of GSH and GSH-related defense enzyme,and reduced the content of H2O2 in Arabidopsis plants under SO_(2)stress.When scavenged endogenous H_(2)S by spraying hypotaurine(HT)during SO_(2)fumigation,the content of GSH,the activities of SOD,CAT and GST were reduced,and the content of MDA was significantly increased in Arabidopsis plants.Together,this study indicated that H_(2)S played an important role in response to SO_(2)stress through improving antioxidant capacity,which would be helpful for better understanding the adaptation mechanism of plants to environmental stress.