The Study On Molecular Mechanism Of Zinc Finger Proteins GIS And ZFP5 Response To Abiotic Stress

During the whole growth period,field crops are often under stress from various environmental factors,such as drought,high salinity,cold injury and high temperature,which can affect photosynthesis,respiration,nutrient transport and metabolism of many substances.Therefore,drought and high salinity are common factors resulting in crop yield reduction and limiting crop yield.In the long history of evolution,however,plants have formed various mechanisms of adaptation and resistance to stress.It can provide important knowledge base for breeding high-quality,high-yield and stress-resistant crop varieties to reveal the molecular foundation underlying these mechanisms and mining gene resources that enhance crop stress resistance.C2H2 type zinc finger proteins,a big group of transcription factor family,play a key role in plant growth and development,including leaf development,morphogenesis of floral organ,trichome development and distribution,as well as stress response process.C2H2 type zinc finger proteins,GLABROUS INFLORESCENCE STEMS(GIS)and ZINC FINGER PROTEIN 5(ZFP5)in Arabidopsis are important transcription factors and reported to mainly regulate the growth and development of trichome.Here,the upstream sequences of GIS and ZFP5 were analyzed and it was found that the upstream sequences of GIS and ZFP5 contain multiple stress response elements.Our results demonstrated that the novel funcaiton of GIS and ZFP5,which are involved in plant response to abiotic stress.Therefore,the role of C2H2 transcription factors ZFP5 and GIS under salt stress and osmotic stress was studied.The main results are listed as follows:1)Under salt and osmotic stress,the germination rate,main root length,proline content,chlorophyll content and activity of reactive oxygen species scavenging enzymes(POD and CAT)of gis mutant were significantly lower than those of wild type.By contrast,those of 35S:GIS line were higher than wild type.qRT-PCR analysis showed that the expression level of GIS was induced by salt and osmotic stress,but not significantly by ABA treatment.Under salt stress and osmotic stress,the expression level of some stress-related genes,such as KIN1 and RD29B in gis mutant was significantly lower than that in wild type,but the level in 35S:GIS line was significantly higher than that in wild type.These results suggest that overexpression of GIS could enhance plant resistance in response to salt and osmotic stress.2)The germination rate,main root length,proline content,chlorophyll content and the activity of reactive oxygen species scavenging enzymes(POD,SOD and CAT)of zfp5 mutant were significantly lower than those of wild type under salt and osmotic stress,while those of 35S:ZFP5 line were significantly higher than wild type under the same stress treatment.qRT-PCR analysis showed that the expression of ZFP5 was induced by salt stress,osmotic stress and ABA.Under salt and osmotic stress,the expression level of stress-related genes was significantly lower than that in wild type,and the expression level of stress-related genes in 35S:ZFP5 line was higher significantly than that in wild type.So it concluded ZFP5 is a positive regulator involved in response to abiotic stress in plant.3)By detecting the difference of germination rate between NbGIS interfering lines and over-expressing lines under salt stress and osmotic stress,it was found that NbGIS,a homologous gene in tobacco,played a negative regulatory role in response to abiotic stress.In conclusion,ZFP5 and GIS were involved in plant responses to salt and osmotic stresses,and the expression of ZFP5 is induced by ABA.Although NbGIS,a homologous gene in tobacco,is involved in response to abiotic stress,its role is different from GIS and ZFP5 in Arabidopsis.