Differential Proteomics Of Medicago Sativa And Arbuscular Mycorrhiza Fungi Under Symbiotic Conditions

Alfalfa(Medicago sativa)is an important perennial forage grass because of its nutrient-rich,good palatability,high grass yield and strong resistance to stress.It is widely planted in animal husbandry area of China,e.g.the southern part of Heilongjiang Province,Hebei Province,the northern part of Anhui Province,Yunnan Province,and the Loess Plateau.Alfalfa and Arbuscular Mycorrhiza fungi(AM fungi)can be well interaction between each other.AM fungi can significantly promote the growth and development,nutrient absorption,product quality and stress resistance of alfalfa.In this paper,TMT based proteomic sequencing was applied to mine differentially expressed proteins between alfalfa infecting by arbuscular mycorrhizal fungi and uninfected roots.Special attention was payed on early differential proteins and metabolic pathways,which is helpful in enriching the underlying mechanism during plant-fungi interaction.The results are as follows:A stable symbiotic system was established after many times of repeats,which provided a reliable foundation for further investigation the symbiotic mechanism between AM fungi and alfalfa.Trypan blue staining showed that AM fungi start to infect alfalfa around 7 days,and symbiosis can be established at 14 days.With prolonged time,the infection rate gradually increased.All of the root length,plant height and biomass of alfalfa infected by AM fungi were significantly higher than that of the control.Proteomic analysis showed that the protein expression of arbuscular mycorrhizal fungi infecting alfalfa was vary.68 proteins in infected roots was up-regulated,while 141 proteins was down-regulated.At 14 days,55 up-regulated and 69 down-regulated proteins in the infected roots was observed.At 28 days,99 proteins were up-regulated and 102 were down-regulated.The differentially expressed proteins were mainly involved in cytoskeletal composition,lignin synthesis pathway,and lipid transport domain,etc.It is very intereting that five Lectin proteins were enriched,and the expressions were found to be significantly different at different stages of symbiosis and the main members showed dynamic changes,which may play a role in the early stage of plant-AM fungal symbiosis.In this study,a stable symbiotic system between alfalfa and AM fungi was established,and the differentially expressed proteins and metabolic pathways in the early symbiotic stage were indentified.The results can enrich the molecular mechanism of plant-microorganisms interaction and is meaningful in improvement the growth and development,nutrient absorption and yield quality of alfalfa,etc.