1.Screening And Identification Of Specific Effectors Of Avirulence And Me3 Virulence Meloidogyne Incognita 2.Study On Bio-control Mechanism Of Clock-controlled Protein Of Endophytic Fungi Acremoniumimplicatum

Root-knot nematodes(RKNs)are one of the most economically important plant-parasitic nematodes(PPNs),infecting more than 5500 plant species.Host resistance and bio-control fungi are considered as the most efficient method to control Meloidogyne incognita.Some virulence population which could overcome the resistant genes(Mi-1,Me3)has been reported.The effectors play a pivotal role in molecular interaction between the root-knot nematode and its host plant.Under natural conditions,the persistence of R gene is closely related to the production,mutation and loss of avirulence effectors.Identification of functional effectors,and its mechanism of host immunity suppression,these results will provide a source of potential targets for the development of new nematicides and some valuable information to predict the durability of nematode-resistance gene.Two parts of research in this dissertation:1.Screening and identification of the specific effectors of Me3 virulence and avirulence Meloidogyne incognita;2.Focus on investigation of the bio-control mechanism of endophytic fungi Acremonium implicatum.Results are summarized as follows:Screening and identification of specific effectors of avirulence and Me3 virulence Meloidogyne incognita1.In order to reveal the molecular basis of M.incognita virulence or avirulence in response to the pepper Me3 resistance,we compared the transcriptomes of avirulence and Me3 virulence near-isogenic lines.Totally 1863 differentially expressed genes were predicted,and among them the number of Me3 virulent nematode(533)were significantly lesser than avirulent(1330).The secretory protein genes of virulent nematodes were significantly deceased,257 in avirulent,and 90 in virulent.There are 16 secretory effectors detected in Me3 virulent nematode,and 29 specific effectors in avirulent nematode.2.Two effectors Minc03867 and Minc11785 with C-type lectin domain were screened in Me3 virulent nematode.In situ hybridization showed that they were located in subventral glands of J2s.Minc03867 and Minc11785 could suppress programmed cell death(PCD)triggered by the pro-apoptotic protein BAX.The VIGS to Minc03867 and Minc11785 could weaken the pathogenicity of virulent nematodes.Overexpression Minc03867 gene in Arabidopsis thaliana can increase its susceptibility to Meloidogyne incognita.Therefore,it was putatived that Minc03867 and Minc11785 as important effectors of Me3 virulent nematode,which had an immunosuppressive function to the resistance pepper.Our results shed light on the mechanism of M.incognita virulence overcome host Me3 resistance gene.3.The specific effector of Mincl0750 was screened in avirulence nematode.Minc10750 gene encodes 115 amino acids,has a signal peptide in N-terminal.Minc10750 located in subventral glands by in situ hybridization,and the expression level of avirulence nematodes was increased significantly in plant.The VIGS to Minc10750 could increase the pathogenicity of avirulence nematodes.Mincl0750 could elicit HR in pepper HDA149.The results indicated that Minc10750 interacted with Me3 gene as avirulence gene.Study on bio-control mechanism of Clock-controlled protein of endophytic fungi Acremonium implicatum4.The endophy fungi Acremonium implicatum shows efficient control effect against root knot nematodes in the greenhouse.In this study,we found a clock-controlled protein(ACR-02291)through genome and transcriptome mining methods.In order to identify the function of ACR-02291,we disrupted ACR-02291 by homologous recombination.The results showed that ACR-02291 could induce the system resistance of tomato plant to resistant the root-knot nematode by split-root experiment.The results provide a theoretical basis for revealing the bio-control mechanism of Acremonium implicatum.