Studies On Indole Sensing Genes And Their Function In Meloidogyne Incognita

Through the screening of 23 allelopathy genes with high homology between Meloidogyne incognita and Caenorhabditis elegans,relative expression levels of these homologous genes were analysed in the process of indole sensing of M.incognita by q RT-PCR.Seventeen homologous genes with significantly up-regulated relative expression levels on AWC,AWA and ASH neurons were selected.And their CDS fragments were cloned forRNA interference experiments.The relative expression levels of homologous genes on AWC neurons have a significant decrease in the attraction of indole after interference,while homologous genes on AWA and ASH neurons have no effect on the chemotaxis of indole after interference.Further experiments confirmed that the signal transduction pathway for AWC neurons to sense indole is:indole binds to the receptor Mi-STR-193,activates the G protein M-GPA-5,and then down activates Mi-ODR-1/Mi-DAF-11,which produces c GMP and then open the cyclic adennucleotide ion channel Mi-TAX-4/Mi-TAX-2.The other neuron AWA,which senses volatile compounds,does not participate in the perception of indole.AfterRNAi of the genes Mi-odr-10,Mi-odr-7,Mi-gpa-6,Mi-plc-1,Mi-egl-8,Mi-ocr-2 and Mi-osm-9 on AWA neurons,Mi-gpa-11 on ASH neurons,the chemotaxis and infection of M.incognita to tomato decreased.The signal pathway of tomato root system on AWA neurons is:the root signal is combined with the receptor Mi-ODR-10,and after activating the G protein Mi-GPA-6,the Mi-PLC-1/Mi-EGL-8 reg?Lated PLC pathway was down-activated to produce the second messengers DAG and IP₃,and PKC was activated to produce the PUFA.And then generates signal transduction to open the TPRV ion channel Mi-OSM-9/Mi-OCR-2.The signal pathway for ASH neurons to perceive the root system is:the root signal combines with an unknown receptor on ASH,and after activating the G protein Mi-GPA-11,it activates an unknown phospholipase pathway downwards,generating signal transduction and opening the TPRV ion channel Mi-OSM-9/Mi-OCR-2.DNA-RNA in situ hybridization with gene probes showed that gene Mi-str-193,Mi-gpa-5,Mi-odr-10,Mi-gpa-6 all have hybridization signals in the head neurons of M.incognita,indicating that these four genes are expressed in the head neurons of M.incognita.This study determined the signal pathways related to sense indole by M.incognita,laying a foundation for the study of the effect of indole on the behavior of M.incognita.Furthermore,we further screened and determined the AWA and ASH signal pathways related to sense tomato roots M.incognita.Interfering recognition of M.incognita to host is a new target for nematode biocontrol.