Effect Of Inoculating Different Arbuscular Mycorrhizal Fungi On The Expression Of Nitrogen And Phosphatetransporter Genes In Roots Of Wheat(Triticum Aestivum L.)

Study the regulation of arbuscular mycorhizal(AM) fungi colonization on the expression of nitrogen and phosphate transporter genes in the roots of wheat is very important to have a better understanding of the mechanisms of the uptake of nitrogen and phosphorus in what-AM association.The thesis investigated the effect of inoculation of four different AM fungi(A.delicata,C.etunicatum,F.mosseaeand R.intraradices) on the experssion of differentnitrogen and phosphate transporter genes.Different inoculation quantities of AM fungi and shade treatments were establishedtostudy the role of carbon allocation signal in regulating the expressionof nitrogen and phosphate transporter gene in wheat-AM association.In addition, new AM inducible expression ammonium transporter(AMT) genes in wheat were cloned.The main results of the thesis are as follows:1. Among the four AM species, only C. etunicatum significantlyincreased the shoot dryweight, total phosphorus and nitrogen uptake of wheat.2.Inoculation of AM fungi mainly locally decreased the expression of Pi-starvationinducible Pi transporter genes(TaPHT1.2 and TaPT4) expression, and all locallyincreased the expression of AM-inducible Pi transporter genes(TRIae Pht1; 10 and TRIae; Pht1; 11).Inoculation with AM fungi either had no effect, or could locally or systemicallydown-regulate the expression of nitrogen transporter genes depending on the type of gene and AM fungal species.3.Wheat rootcolonization rate increased with different quantity ofinoculation.AM inoculation treatment significantly increased the shoot biomass, theuptake of nitrogen and phosphorus, photosynthetic capacity as well as the accumulation of photosynthetic productcompared to non-inoculated plant. The growth parameters of wheat is significantly higher in the largest quantity(200 g AM inoculum) inoculating treatmen than the minimum quantity(20 gAM inoculum) inoculating treatment.Shade treatment significantly decreasedthe growth parameters of wheat. Inoculation AMfungisignificantly down-regulated theexpression of phosphate transporter(PHT1.2 and PT4) genes and nitrogen transporter genes(NRT1.1,NRT1.2, NRT2.1, NRT2.2 and AMT1.2) compared to non-inoculated plant, but there is nosignificant difference between different inoculation quantity treatments.Shade treatment had no effect on the expression of nitrogenand phosphate transporter genes.4. The protein structure characteristics of the new AMT gene(D-AMT) is similar with other AMT genes.The new gene have highly homologouswith the AMT genes in Aegilops tauschii, Brachypodium distachyon and Oryza sativa. Gene quantitative analysis showed that the expression of D-AMT is mainly in the root of wheat, and induced by AM fungi colonization. The expression of this gene in leaves and stem was very low. The fluorescence in situ hybridization(FISH) analysis indicated that the D-AMT gene expressed in the cell membrane.