Migation Of Azorhizobium Caulinodans In Wheat And Transcriptome Analysis Of Their Interaction

Rhizobia not only interact with leguminous plant, forming root nodules on biologicalnitrogen fixation, but also can be used as endogenous bacteria with non leguminous plants,and have certain role in the growth of non leguminous plants. But the interaction mechanismis not clear at present. This research adopts Confocal laser scanning microscope,high-throughput sequencing and quantitative real time PCR technology，probing into themigration of A.caulinodan ORS571in the wheat and interaction mechanism.With gfp-A.caulinodans infecting the roots and leaves of wheat respectively, we find thatgfp-A.caulinodans can invade wheat cortex tissue passing throught the lesions of root andlateral root fractures, colonization of intercellular space in cortex and the vascular bundletissues the inoculation of root6days later; root inoculation after12days, gfp-A.caulinodansmoves to leaf tissue, distribution around leaf stoma. Leaf inoculation6days later,gfp-A.caulinodans distribute the gap of mesophyll cells， around the lesions and porosity, notfound distribution of the root; Blade12days after inoculation, gfp-A.caulinodans scatter inroot cells clearance. This thoroughly shows that gfp-A.caulinodans there is a certain ability tomigrate in wheat.With high-throughput sequencing technologies sequencing the transcriptome to the totalRNA of30samples at eight times. At the same time we sequence mRNA expression profile atfive times respectively. The Unigenes annotate to25COG functional category bytranscriptome sequencing, the main classification function are transcription, translation, andcell division, cell cycle regulation, modification after translation, transshipment andcarbohydrate metabolism. These features are the most important function of cell growth,reproduction and metabolism, illustrating the the Unigenes have a basic ability as a referencelibrary. Expression profile sequencing results show that the6h,12h,24h,48h differencegenes of the underground part have25,45,152,44difference genes respectively; the6h,12h,24h,48h difference genes of the underground part have2,309,1and48difference genesrespectively. With real time quantitative PCR technology detecting4defense related genesexpression differences at five time points, we find the PR1and MYC do not differ basicly,COI2differences appear in the48h, ACC differences are the biggest differences at12h and24h, become smaller after48h. PR1gene is a member of the Pathogenesis Related Proteins Family, it does not show the difference shows that wheat seedling inoculation did not occurSystemic Acquired Resistance (SAR). COI2as a key gene of jasmonic acid pathway, itexplain jasmonic acid pathway begin to activate by raising the expression at48h. ACC is thekey gene to the ethylene synthesis and its increase augur ethylene pathway is activated in12hand24h, but it’s smaller differences after48h, ethylene synthesis increase may antagonise itsupstream key enzyme synthesis in turn.To sum up, A.caulinodans ORS571has a certain ability to migrate in wheat, the REDOXenzyme and cellulose synthase, hydrolytic enzymes and genes of Induced SystemicResistance related pathways change after its invasion, thus A.caulinodans ORS571willinfluence on wheat grows and enhance the ability of wheat seedlings to resist bacteriainfection. This lays a certain foundation for A.caulinodans ORS571as bio-bacterial manure inthe future.