Proteomics Study Of Signal Molecule H₂S Alleviating Low Temperature Stress In Rice

Hydrogen sulfide(H2S)played an important role in human and animal physiology.Its ubiquity and versatile properties had recently caught the attention of plant physiologists and biochemists.In spite of the H2S was a toxic gas,its role had been researched for more than 300 years.Until the mid-1990-s,the hydrogen sulfide(H2S),together with nitric oxide(NO)and carbon monoxide(CO)was identified as a new type endogenous gaseous signal molecular.In this report,we took rice as experiment material,by 10? low temperature stress treatment and 25? as room temperature control to investigate the effects of exogenous hydrogen sulfide on rice seedlings growth and development,cell submicroscopic structure and leaf protome changes using mass spectromtry tecnology.We hoped to explore the molecular mechanism of H2S relieving rice in low temperature stress.The results showed as follows:1?Rice seedlings treated with low concentration(0.1?0.8 mmol/L)NaHS exhibited a significant increase in seedling growth(including plant height,root length and biomass),chlorophyll content,net photosynthetic rate(Pn)and chlorophyll photochemical rate(Fv/Fm).And then the relative electric permeability of leaves decreased.However,with the increasing of concentration of NaHS,the growth of seedling significantly was suppressed.PCA analysis indicated a distinct separation between control and treated profiles,especially,low concentration(0.1?0.8 mmol/L)NaHS and the control,and high concentration(1.6?3.2 mmol/L)NaHS and the control.2?We analyzed the protein changes in treatment groups compared with control group after treating with different concentrations of H2S by two-dimensional electrophoresis(2-DE)technonology.Mass spectrometry analysis helped to identify 32 protein spots which expression changes more than two times.These identified proteins were mainly included:photosynthesis related protein(43%),energy metabolism related protein(9%),redox equilibrium type of protein(13%),protein synthesis,folding,processing and degradation of proteins(19%),signal transduction protein(3%),and other proteins(13%).These proteins involved in various cellular responses and metabolic pathways,which had a great correlation with the response of cell physiological changes under H2S treatment.3?Rice seedlings treated by low temperature(10?)showed stress phenotypes of narrow leaf blade,hairy leaves,yellowness.The plant height,root length and biomass of low temperature group were less than the normal temperature group and normal temperature plus 0.4 mmol/L NaHS.While,it could obviously alleviated by applying 0.4 mmol/L NaHS,which could relieve the inhibition of low temperature stress on rice growing,also reduce the loss of chlorophyll content.Among more than 126 leaf total protein spots detected on two-dimensional electrophoresis gels,11 proteins were up-regulated and 46 proteins were down-regulated.4?Low temperature stress induced rice seedling energy cost increase.It led to fructose diphosphate aldolase,active adenosine methionine,malic enzyme and other protein significantly increase.Meanwhile,expression quantity of photosynthesis related proteins such as ribulose bishosphate carboxylase,iron redox proteins significantly rose.Some specific proteins such as temperature induced lipocalin-like protein and cold shock protein-1 expressed.Based on the above results,we believed that the low temperature stress increased rice ultra oxygen free radical,reduced photosynthesis.H2S reduced the damage from cold by adjusting expression of protein involved in energy metabolism,photosynthesis related protein and specific protein response to low temperature stress.This research may lay a prelimary foundation about the response mechanism on H2S alleviating low temperature stress in rice seedling from the molecular level.