Influence Of Signal Substances On The Expression Of Nitrogen And Phosphate Transporter Genes In Roots Of Wheat(Triticum Aestivum L.)Associated With Arbuscular Mycorrhizal Fungi

Previous studies report that the colonization of arbuscular mycorrhizal(AM)fungi can regulate the expression of nitrogen(N)and phosphate(Pi)transporter genes in the roots of wheat,but the mechanism of this effect remains unknown.This study aims to test the hyphothesis that N/Pi signals transferred by the AM extra-radical hyphae and molecular signals during the formation of AM symbiosis can regulate the expression of N/Pi transporter genes in roots of wheat associated with AM fungi.A three-compartment culture system was established,and the expression of nitrate transporter(NRT),ammonium transporter(AMT)and Pi transporter genes was quantified using real-time PCR method.The main results are as follows:1.The expression of one Pi-starvation inducible Pi transporter gene(TaPT4),one NRT gene(TaNRT2.2)and one AMT gene(TaAMT1.2)were down-regulated by AM colonization only when roots of host plants received Pi and N signals,but the expression of another Pi-starvation inducible Pi transporter gene(TaPHT1.2)and three NRT genes(TaNRT1.2,TaNRT2.1,and TaNRT2.3)was down-regulated by AM colonization,regardless of whether there was Pi and N transfer from AM extra-radical hyphae.2.Three molecular signals during the formation of AM symbiosis Strigolactones(SLs),flavonoids,and Lyso-phosphatidylcholine(LPC)can regulate the expression of four nitrate transporter genes(TaNRT1.1?TaNRT1.2?TaNRT2.1 and TaNRT2.3),but did not regulate the expression of all the phosphate transporter genes;The Myc-Factor addition significantly down-regulated the expression of TaNRT1.2 and TaNRT2.1;and also up-regulated the expression of one AM-inducible Pi transporter gene(TaPT10),but did not influence the expression of Pi transporter genes involved in the direct Pi uptake pathway.