Physiological And Biochemical Studies Of OslCE1 Gene Enhancing Low Temperature Resistance In Rice

In the natural environment,plant growth and development is inevitably affected by low temperature stress.ICE(inducer of CBF expression)is a kind of bHLH transcription factors that plays an important role in plant stress resistance.But the mechanism of ICE in responses to low temperature stress is still not completely known.First,the ICE gene and protein sequences from different species,including mosses,ferns,gymnosperms and angiosperms,were searched.All sequence alignments were performed using program Clustal X,and the evolutionary tree was constructed by neighboring-joining method to further understand the molecular evolution patterns of ICE gene.The results showed that,ICE protein family is grouped into mosses,ferns,gymnosperms,monocots and dicots,respectively.Although ICE sequences from different sources have some differences,but HLH domains in each plant species has a very good conservation,which indicates the conservation of ICE genes family in evolution.In addition,it was also found that the formation of angiosperms different branches,indicating the original of monocots and dicots ICE genes may be different.Secondly,OsICEl transgenic and non-transgenic rice germplasms were used to study the effects of OsICEl gene on physiological,biochemical indice under low temperature stress.The seedling of OsICEl transgenic and non-transgenic rice were treated with 6℃low temperature,and the phenotype,biomass,survival rate,electrical penetration and other indicators were analysed.The results showed that OsICE1 overexpressing transgenic plants(C1-T12,C2-T25,C3-T7,C4-T5)are growing better than the control plants(WT)based on plant height,color of leaves and root length of rice seedlings,and antisense expressed transgenic plants(C5-T21)are growing worse than WT.The fresh weight,dry weight and survival rate of transgenic plants(Cl-C4)are significantly higher than that of the control plants.Photochemical efficiency of chloroplast PSII and Net photosynthetic rate also shows that transgenic plants better than the control plants.These results indicated that OsICEl gene enhancer rice seedlings to cold stress tolerance.Thirdly,comparative transcriptomic and proteomic patterns were investigated on the leaves of OsICEI transgenic and control plants under low temperature 49 differentially expressed proteins were detected in response to low temperature,and they were mainly involved in the photosynthetic process,defense response,signal transduction,metabolism,protein synthesis and degradation,ion transport,redox balance and other processes,and the largest proportion of identified proteins is photosynthesis-related protein.All these results provide a basis for further elucidation of physiological and molecular mechanism of OsICEI gene on enhancing tolerance of low temperature.