The Effects Of Arbuscular Mycorrhizal Fungi (Glomus Tortuosum) And Rhizobia (Rhizobium Leguminosarum) On Growth And Proteome Of Pisum Sativum

Plants can establish intracellular symbiosis system with symbiotic fungi and bacteria in their roots through their own signal pathway,which are an important part of terrestrial ecosystems.The symbiotic system established by plants,Arbuscular mycorrhizal fungi（AMF）or Rhizobium is the most widely distributed and typical symbiotic system in terrestrial ecosystems.At present,there are many studies on the interaction between AMF or Rhizobium with plants,but there are few studies on the interaction when they exist together.The results of the research are also different due to the difference of Glomus,Rhizobia and plants used in the experiment.There are still many unknowns about the relationship between AMF symbionts and rhizobia symbionts,and it is necessary to deepen the exploration of the interaction mechanism among AMF,rhizobia and plants under co-inoculation.We designed a pot experiment with no inoculation（AM-R-）,the Pisum sativum of single inoculation with Rhizobium leguminosarum（AM-R+）or Glomus tortuosum（AM+R-）,and double inoculation Rhizobium leguminosarum and Glomus versiformis（AM+R+）were used as the object.In this way,we explored the effects of the interaction between AMF and Rhizobium on the growth and development of peas（biomass,yield,N content,P content,and root traits）.How does AMF and rhizobium co-inoculation affect pea nodulation and AMF infection at seedling and grain filling stage;and how does the antioxidant system of peas change under the influence of AMF and rhizobium?Many studies have shown that arbuscular mycorrhizal fungi and rhizobia can affect pea biomass,yield,root traits,N content,P content,antioxidant system and proteome.Through the above experiments,we found that:1.After inoculating AMF alone（AM+R-）,the total biomass（fresh weight）of peas increased by 29.47%,the yields of fresh peas and dry peas increased by 39.35%and50.24%;P content increased by 119.39%,root,The P content of shoots and pea pods increased by 47.51%,107.86%and 176.20%,respectively.When co-inoculated with AMF and Rhizobium（AM+R+）,the total biomass（fresh weight）of peas increased by44.54%,and the yields of fresh and dry peas increased by 51.18%and 98.99%,respectively;The P content of,shoots and pea pods increased by 34.94%,134.91%and174.49%,respectively.1.After inoculation with AMF alone（am+R-）,the total biomass（fresh weight）of pea increased by 29.47%,and the yields of fresh pea and Dry Pea increased by 39.35%and 50.24%respectively;The content of total P increased by 119.39%,and the content of P in root,shoot and pea pod increased by 47.51%,107.86%and176.20%,respectively.When inoculated with AMF and Rhizobium（AM+R+）,the total biomass（fresh weight）of pea increased by 44.54%,and the yield of fresh pea and Dry Pea increased by 51.18%and 98.99%;The content of total P increased by 118.53%,and the content of P in root,shoot and pea pod increased by 34.94%,134.91%and174.49%respectively.2.The root’s length,surface area and volume of pea did not change under all experimental treatments,but the root diameter of pea under co-inoculated（AM+R+）treatment decreased by 24.11%.Under the condition of co-inoculation of AMF and Rhizobium（AM+R+）,the nodulation number of pea at seedling stage and filling stage increased significantly,by 439.30%and 137.79%;However,AMF infection decreased by 50.95%at seedling stage,but there was no significant difference at grain filling stage.3.The antioxidant system of peas changed under different treatments;when inoculated with AM fungus（AM+R-,AM+R+）,the CAT enzyme activities in pea leaves increased by 47.54%and 23.00%,respectively,and the POD enzyme activities decreased by 66.16%and 66.16%,respectively.19.64%;there was no significant change in CAT and POD enzyme activities in pea root.However,compared with peas inoculated with Rhizobium（AM-R+）,the root POD decreased by 66.62%and 60.45%,respectively.The content of MDA decreased by 29.41%when inoculated AMF alone（AM+R-）,and decreased 35.30%under co-inoculated.4.The results of proteomics showed that most of the carbon metabolism related proteins of pea were down-regulated after inoculation with AMF（AM+R-and AM+R+）,but the pentose phosphate pathway（especially the non oxidative step）,photorespiration and a small amount of pentose phosphate pathway related proteins were significantly up-regulated in leaves;At the same time,the expression of peroxisome,MAPK signaling pathway and other related proteins were significantly down regulated.Our results show that AMF can improve the phosphorus content,biomass,pea pod yield and nodulation ability of peas;and when co-inoculated with Rhizobium（AM+R+）,the improvement of pea yield is even better.AMF promotes pea nodulation,but arbuscular mycorrhizal fungi colonization is significantly reduced at the seedling stage in the presence of rhizobia.This difference may be due to the fact that at the seedling stage,AMF mainly promotes pea nodulation through the release of symbiotic signals;at the grain filling stage,it is mainly caused by the enrichment of rhizobia into the pea rhizosphere through the underground mycelial network to promote pea nodulation.After inoculation AMF alone（AM+R-）,the POD enzyme activity of peas decreased,but the CAT enzyme activity increased;this indicates that the scavenging method of H₂O₂ in peas may have occurred Altered,peas inoculated with AMF scavenge H₂O₂primarily by CAT enzymes.