Effect Of Arbuscular Mycorrhizal Fungi On Vicia Sativa Anthracnose

The present research was aimed to study the effects of arbuscular mycorrhizal fungi on the anthracnose of common vetch cv,Lanjian No.3 caused by Colletotrichum lentis and the regulation mechanism.The main findings are as follows:1.Colletotrichum lentis infection caused round or elliptical lesions on the leaves and stems of common vetch,which were dark brown.The pathogen decreased the aboveground and underground biomass of common vetch by 41.29%and 20.69%,respectively,the number of effective nodules was decreased by 42.25%.The pathogen also increased plant shoot polygalacturonase activity by 33.09%,increased pectin methyl esterase activity by 10.74%,but had no effect on plant lignin content,jasmonic acid content and peroxidase activity of the plant（P>0.05）.In common vetch roots,the infection of pathogen increased jasmonic acid content by 70.34%,and the lignin content was increased by 26.77%,but there was no significant difference on activities of peroxidase,polygalacturonase and pectin methylesterase（P>0.05）.2.AM fungi significantly reduced the occurrence of anthracnose on common vetch.Glomus mosseae and G.tortuosum delayed the occurrence of anthracnose for three days,decrease the disease incidence by 60.65%,decrease disease index by45.37%.AM fungi could promote plant growth and N,P absorption.Compared with the control,the shoot biomass was increased by 18.44%⁵4.92%,and the root biomass was increased by 25.68%⁸4.68%;the N and P contents of plant shoot were increased by 58.71%¹23.58%and 20.57%⁶3.58%,respectively,which was increased by 54.60%¹09.02%and 30.42%¹07.12%in plant roots.3.AM fungi increased the defense enzyme activity of common vetch significantly.The activities of POD,CAT and PPO increased by 73.50%,24.40%and36.55%,the activity of chitinase increased by 95.21%;AM fungi also increased the contents of signaling molecule,e.g.,jasmonic acid content was increased by 105.53%and the salicylic acid content was increased by 40.09%;the proline content showed a positive response to the colonization of AMF,while the malondialdehyde content showed negative to AMF colonization.After AM fungi colonization,the proline content was increased by 236.80%,and the MDA content was decreased by 78.57%.4.The transcriptome sequencing showed that there were 27,871 differentially expressed genes（DEGs）in NM-AM,26,760 DEGs in NM-NMP,34,837 DEGs in AM-AMP,and 30,193 DEGs in NMP-AMP.A number of these differential genes are related to the synthesis and metabolism of pathogenesis-related proteins such as chitinase proteins,peroxidase family proteins,glycoprotein family proteins and so on.These differential genes were mainly enriched in multiple metabolic pathways such as plant-pathogen interaction（ko04626）,MAPK signaling pathway-plant（ko04016）,plant hormone signaling transduction（ko04075）,and phenylpropanoid biosynthesis（ko00940）.In summary,AM fungi promote the growth of plant,regulate carbon and nitrogen metabolism,increase the activity of antioxidant enzymes and the differential expression of genes,improve the ability of host plants to scavenge peroxides such as O².-and H₂O₂,enhance the antioxidant levels of plant cells,thus reduce the damage to cell membranes,AMF also enhance the reactive oxygen species（ROS）scavenging ability of the host,thereby alleviating the inhibitory effect of pathogen on plant growth and causing damage to plants.