Study On The Regulation Mechanism Of Self-Incompatibility Plasticity In Nicotiana Alata

Nicotiana tabacum L is an important cash crop in China,but the Nicotiana tabacum L is narrow in hereditary basis,and it is poor resistance to adversity and disease.While many wild tabacum species persist the traits of pesticide resistance and adversity stress tolerance.It is natural gene bank to improve cultivated tobacco species,such as Nicotiana alata Link&Otto have good resistance to wildfire disease,black root rot,powdery mildew and spotted wilt virus,but it is self incompatibility.The research group obtain N.alata materials with different morphology or self compatibility:N.alata-N2 with self incompatibility plasticity it can regulate self breeding.In this paper,the S genotypes were identified of 3 varieties of N.alata materials,a study of the N.alata exist self incompatibility plasticity in different developmental stages of pistil and plant,the differences of self incompatibility regulated key genes in transcriptional and protein levels.To explore the regulation mechanism of self incompatibility plasticity this material.By comparing the expression difference of self incompatibility regulated key genes in two varieties of N.alata with different self incompatibility intensity.The regulation mechanism of strict self incompatibility of N.alata?PI 42334?was explored preliminarily.The specific research contents are as follows:?1?By designing homologous primers and gene specific primers,the S-genotypes of 3 of N.alata materials?N.alata-N1,N2 and N3?were cloned and identified.This result show that S-genotype of N.alata-N1 and N2 is S₆S₆,but S-genotype of N.alata-N3 is S₇S₇,and the morphological differences are large between N.alata-N1and N2,but both all can Self breeding.N.alata-N3 is self incompatible strictly.?2?Previous studies showed that N.alata-N2 self compatibility is increasing and can self breeding during the development and senescence of pistil and plant.In this study,the self incompatibility related genes were detected by RT-qPCR.Transcriptional differences associated with the development and senescence of pistil and plant.This result show that:S₆,120 kDa,HT-b,TTS,NAG and other self incompatibility regulation gene are associated with the growth and senescence of pistil and plant,and the transcriptional amount is reduced,indicating the change of gene transcriptional level,It may be related to the regulation of N.alata-N2 self incompatibility plasticity.The transcription of Trxh and NaStep genes is irregular change with development of pistil and plant.?3?Further determination key protein of self incompatibility regulation-S-RNase with development and senescence of pistil and plant.The change law of enzyme activity.A monoclonal antibody against self incompatibility related protein 120 kDa and HT-b was obtained by prokaryotic expression antibody chip screening technique.Western-blot studies the protein change of expression associated with the development and senescence of pistil and plant.This study show that,during the senescence of pistil and plant,S-RNase activity decreased relatively,but the S-RNase activity remained high in pistil,and expression of 120 kDa and HT-b protein are decreasing.This result further explore the self incompatibility plasticity regulation mechanism of N.alata-N2 in protein level.?4?The difference of self incompatibility related genes of N.alata-N2 and N.alata-N3 materials in the transcription and S-RNase activity,The difference of expression of 120 kDa and HT-b protein in N.alata-N2 and N.alata-N3 materials,to explore the regulation mechanism of difference self incompatibility between 2 N.alata materials.The related genes transcriptional,S-RNase activity,120 kDa and HT-b protein expression in N.alata-N3 materials are higher than N.alata-N2.This may be related to the higher self compatibility of N.alata-N2 than N.alata-N3.In conclusion,the two N.alata materials?N.alata-N1 and N2?with large morphological differences are all S₆S₆,this coincides with the result of the two materials can self breeding.But the S-genotype of N.alata-N3 is S₇S₇.With developmenting and senescencing of pistil and plant,120 kDa and HT-b gene transcriptional and protein expression level are reduced.It is suggested that 2 genes may regulate the plasticity of self incompatibility from transcription and translation level.S-RNase activity is still relatively high in senescent pistil,it is suggested that S-RNase enzyme may not directly participate in regulating the plasticity of self incompatibility.S-RNase enzyme activity,120 kDa and HT-b gene transcription and protein expression in N.alata-N3 were higher than N.alata-N2.This may guarantee the gene product content of self incompatibility regulation is higher than threshold of exert function in pistil different developmental stages,to control self incompatibility of N.alata-N3.This paper explore the regulation mechanism of self incompatibility plasticity in N.alata,and the reason exists differences in self incompatibility among different materials.It has important guiding significance for the preservation germplasm resources and cultivation of new resistant varieties of N.alata.