The Research Of Disease Resistance To TMV In Tobacco Enhanced By Trehalose Treatment

Tobacco mosaic disease is one of the main diseases from the production process of the flue-cured tobacco.It appears in tobacco-growing area all over the country and becomes a growing problem.Plants are infected with tobacco mosaic disease usually growing difficult,abnormal,dwarf or even dead.The problem creates great economic losses to tobacco growers.It's also difficult to prevent and cure the tobacco mosaic disease.The biological way to prevent and cure the tobacco mosaic disease has gained much more focus because it is economical and practical compared with the agricultural agriculture way and the chemical preparation way,which makes use of the extractives from plants or microbes.Trehalose is a kind of non-reducing disaccharide which exist widely in nature.It has the special physicochemical properties which effectively protects protein molecules from denaturalization and deactivation and maintain the organisms' vital processes and biological characteristics under some stress conditions such as high temperature,alpine-cold,high osmotic pressure and dehydration.Previous studies have proved that trehalose is associated with the disease resistance and stress response of plants.We can enhance the tolerance of plants about biotic stress as drought,low temperature,salt damage etc,and abiotic stress as diease,insect pest and so on,by both the transgenic technology to increase the synthesis of the trehalose in plants or the treatment of exogenous trehalose.However,there are no researches about the influences of trehalose on tobacco mosaic disease.Therefore,we use Nicotiana glutinosa and Nicotiana tabaccum cv.K326 as our experimental material to test the role of different concentrations of trehalose?10 mmol/L and 50 mmol/L?in enhancing the resistance to TMV.We also test the changes of POD,SOD,proline,MDA,the contents of soluble sugar and the expression levels of APX,Rboh D and Rboh F in the tobacco leaves with different concentrations of trehalose?10 mmol/L and 50 mmol/L?in different periods of time?2 h and 24 h?.We can elucidate the effects of trehalose on the stress resistance and disease resistance of tobacco by this test.At the same time we get the preliminary analysis on its molecular mechanism by the stomata experimentand the transcriptome sequencing.The analysis results are as follows:?1?Through a method of half leaf blight spot,trehalose can passivate,prevent and cure TMV.Through the stomata opening and physiological index detection,a preliminary that the spraying of trehalose may induce the generation of reactive oxygen species through activating NADPH oxidases,increase osmotic regulation substances,induce a vast accumulation of PR to enhance diease resistance of tobacco.?2?Through the transcriptome data analysis found that trehalose can promote expressing of disease resistance related genes in leaves.At the early stage of the tobacco response to trehalose,a large number of HSP,HSP90 interacted with disease resistance RPP8-like protein3,HSP70 interacted with BAX gene inhibitor which has the function of promoting apoptosis,as well as the PP2 C,LRR-RLK,Ca M,-CCCH zinc finger domain protein,JAZ and 8'-abscisic acid hydroxylase and various disease-resistant proteins,induced the resistant function of tobacco.Within 24 h,a large number of resistant proteins,such as PR and WRKY appeared and enhanced disease-resistant ability of tobacco in many aspects.?3?Through the analysis of transcriptome data,it was found that trehalose could promote the expression of anti stress related genes in tobacco leaves.Trehalose treatment after 2 h,HSP,PP2 C,Ca M,-CCCH zinc finger domain protein,JAZ and 8'-abscisic acid hydroxylase encoded genes expressed in tobacco,Trehalose treatment after 24 h,BHLH transcription factor?F-box protein and Amino acid/auxin permease?Aux/IAA family,ARR and CRE encoded genes expressed.Compared with 2 h and 24 h,the application of trehalose could activate ABA,JA,Ca²⁺and other signal pathways to enhance resistance of tobacco.