Preliminary Research On Nitrogen Uptake And Growth Of Tobacco(Nicotiana Tabacum L.) With Inoculation Arbuscular Mycorrhiza Fungi

The root systems of most land plants can form AM symbiota with arbuscular mycorrhizal fungi?AMF?,which has a positive effect on improving nutrient absorption of host plants,promoting growth and development,and alleviating environmental stress.In this study,tobacco?Nicotiana tabacum L.?was used as the host plant,based on Funneliformis mosseae?Fm?,Rhizophagus intraradices?Ri?,and Claroideoglomus etunicatum?Ce?,Gigaspora margarita?Gm?,four AMF strains and three varieties with different nitrogen efficiencies?ZY100,K326,NC89?were screened for strain and variety combinations;secondly based on screening results Using 15N isotope tracing method to explore the preferred form of AMF for nitrogen absorption;based on the above research results,using 15N stem injection method to explore the effect of AMF on nitrogen transfer in intercropping mode;finally using high-throughput transcriptome sequencing method to tobacco plant root system Nitrogen metabolism analysis was performed.The main conclusions of this article are as follows:?1?All four AMF strains can infect the root system of tobacco plants,and the infection rate is 21.82%?41.6%.Without inoculation,different nitrogen-efficiency varieties have different plant height,dry matter content,root growth status,nutrient content?N,P,K,Ca,Mg,Fe,Mn,Cu,Zn?,nitrogen metabolism enzymes?NR,GS?and related nitrogen metabolic enzyme gene expression?NRT1,Ni R1,Ni R2,Ni R3,Nt GS1,Nt GS2?and other indicators are generally expressed as ZY100?low?<K326?medium?,NC89?high?.In the case of AMF inoculation,the above indicators have been promoted to a certain extent,but the effect varies depending on the type of strain and tobacco variety.In general,the low nitrogen efficiency variety?ZY100?inoculated with Ce had better growth promoting effect.?2?Using?NH⁴?₂SO₄,KNO₃,Glu and their corresponding ¹⁵N markers as the nitrogen source,the experimental exploration of the main nitrogen forms absorbed by AMF showed that there were significant differences in the absorption of AMF to each nitrogen form.The absorption of ¹⁵N-Glu labeling treatment?N3?is significantly greater than that of non-labeling treatment?N0?,indicating that AMF can absorb a certain amount of Glu.When?NH₄?₂SO₄,KNO₃,and Glu coexist in nitrogen form,AMF preferentially absorbs NH₄⁺,and its absorption is 1.35 and 2.94 times that of NO₃^-and Glu,respectively.In terms of the total nitrogen absorbed,?NH₄?₂SO₄,KNO₃,and Glu each accounted for 48.61%,36.10%,and 15.29%of the total nitrogen absorption.?3?Compared with non-inoculation?CT?,single inoculation CE,and single inoculation BJ in soybean/tobacco intercropping system,the double inoculation?CE+BJ?improved.The absorption of nitrogen by soybeans increased by 93.1%,28.71%,and 39.62%respectively;under the same PS treatment,the absorption of N by tobacco plants with double inoculation?CE+BJ?was uninoculated?CT?and single inoculated CE,1.68,1.22 and 1.28 times of single inoculation BJ treatment.Based on the 30?m nylon mesh separation?MS?double inoculation system?CE+BJ?,the amount of nitrogen transferred from soybean to tobacco plants increased by 7.29,6.97,and 11.52 mg/pot compared to CT,CE,and BJ,respectively.In the non-separated system?NS?,the double inoculation of tobacco strains?CE+BJ?increased by 6.44,7.63,mg/pot and 12.48 mg/pot compared with CT,CE,and BJ,respectively.In summary,simultaneous inoculation of CE and BJ in the soybean/tobacco intercropping system improves the biomass accumulation of the intercropping system and promotes the nitrogen transfer from soybean to tobacco plants.?4?Root transcriptome sequencing analysis showed that,compared with the uninoculated treatment?CK?,the tobacco inoculated juvenile Glomus vulgaris?Ce?identified four nitrate transporters?NRT1.10,NRT1.1,NRT1.7,NRT1.11?,4polypeptide transporters?PTR3-A,PTR1,PTR2,PTR5?,5 ABC superfamily transporter proteins?At ABCB4,At ABCB10,At ABCB14,At ABCB17,At ABCB18?and 6 nitrogen metabolic enzyme genes?GS2,GLUL,GLTB,GLTD,GLT1,GDHA?.Inoculation with Rhizoctonia solani?Ri?,identified 1 high affinity nitrate transporter2.5?At NRT2.5?,7 nitrate transporters?NRT1.10,NRT1.7,NRT1.11,NRT1.1.NRT1.1,NRT1,NRT2?,3 polypeptide transporters?NRTPTR3-A,NRTPTR1,NRTPTR5?,7 ABC superfamily transporter proteins?At ABCB4,At ABCB5,At ABCC10,At ABCC14,At ABCB19,At ABCB17,At ABCB18?and 8 nitrogen metabolic enzymes?GS2,GLUL,GLUD1,FM,CA,GS,GDH1,GDH2?.As far as the types of nitrogen transport proteins and nitrogen metabolic enzymes identified by AMF inoculation are concerned,Ce inoculation mainly involves the glutamate metabolism pathway,while Ri inoculation is fully involved in glutamate metabolism,cyanoamino acid metabolism,methane metabolism and Glyoxylic acid metabolism pathway.The results showed that different AMFs had different nitrogen absorption,assimilation ability and involved nitrogen metabolism pathways..