Identification Of Tobacco FtsH Gene Family And Preliminary Study On Stress Resistance Of FtsH7 Gen

Roasted tobacco is an important economic crop in China,and high quality roasted tobacco should have high quality,suitable yield and strong resistance to adversity.Due to the frequent occurrence of low temperatures,droughts and other adverse weather in recent years,this has led to the frequent occurrence of slow growth and small,thick leaves,which seriously restrict the development of tobacco quality and yield.The study of resistance in roasted tobacco is receiving more and more attention,so the excavation and identification of resistance genes is of great importance for the selection and breeding of varieties and the establishment of new germplasm resources with good resistance,etc.Filamentous temperature-sensitive H proteases are widely found in plants and possess ATPase activity,molecular chaperone activity,and protein hydrolase activity.It has been found that fts H proteases play an important role in plant growth and development,as well as in plant response to adversity stress,and are potentially useful for the development of new germplasm resources.Therefore,in this study,we identified members of the tobacco fts H protease gene family based on whole genome sequences,analysed the physicochemical and protein-related properties of the gene family proteins,and used RT-q PCR to analyse the expression patterns of some members of the tobacco Ntfts H gene family in different tissues such as roots,stems and leaves,as well as under different stresses such as low temperature and drought.The overexpression vector of Ntfts H7 was constructed and genetically transformed into K326,the main tobacco variety in Guizhou,using the leaf disc method,and the transgenic plants overexpressing the Ntfts H7 gene were analysed for their functional resistance to drought and low temperature.The main findings are as follows:1.20 genes encoding fts H proteases were identified by gene family identification,located on 13 chromosomes;the molecular weights of the encoded proteins ranged from 51.15 k Da(Ntfts H9)to 135.53(Ntfts H3)k Da,the lengths ranged from 456 aa(Ntfts H9)to 1239(Ntfts H3)aa,and the isoelectric points ranged from 5.61(Ntfts H13)to 11.17(Ntfts H18).The number of introns in the20 Ntfts H genes ranged from 3 to 27,and the gene structure was similar to that of homologous genes in Arabidopsis and pear,and the gene structure was more homologous to that of the dicotyledonous plant Arabidopsis.The Ntfts H gene has fragmentary duplications within the genome,but no tandem duplications;there are co-linear blocks with Arabidopsis,rice,tomato,pepper and potato.GO annotations focus on three aspects: biological,cellular and molecular processes.2.The tobacco Ntfts H gene family has tissue-specific expression,with relatively high expression in calyx,leaves and roots.The expression of four members of the Ntfts H gene family(Ntfts H3,Ntfts H5,Ntfts H7 and Ntfts H12)was responsive in three different tissue sites in the root,stem and leaf under nine single-factor treatments,including low temperature,drought,high temperature,Na Cl,UV,bright light and IAA,SA and GA3,indicating that the Ntfts H gene family may be involved in the The Ntfts H gene family may be involved in a complex intersection of network regulation in response to abiotic stresses as well as hormonal responses in tobacco.3.Compared with wild-type plants,plants overexpressing the Ntfts H7 gene showed increased SODase and CAT enzyme activities,reduced oxidative substances such as superoxide anion,malondialdehyde and hydrogen peroxide,and significantly increased osmoregulatory substances such as proline and soluble sugar when exposed to drought and low temperature stress,which effectively improved the resistance of transgenic tobacco to stress.The Ntfts H7 gene was effective in improving the resistance of tobacco to low temperature and drought stress.In summary,we have conducted a comprehensive analysis of the Ntfts H gene family and investigated the potential role of Ntfts H genes in tobacco in the face of adversity stress through gene expression analysis and phenotypic and related enzyme activity changes in Ntfts H7 overexpression plants under adversity conditions,and also demonstrated that overexpression of Ntfts H7 genes can enhance the resistance of tobacco plants to low temperature and drought,providing a reference for the study of the function of tobacco Ntfts H genes and the creation of new germplasm resources.