The Identification And Functional Characteration Of Effectors From Meloidogyne Incognita

Meloidogyne incognita is highly specialized parasite that interacts with host plants using a range of strategies.The effectors are synthesized in the esophageal glands and secreted into plant cells through a needle-like stylet during parasitism.In this study,based on RNA-seq and bioinformatics analysis,we predicted 110 putative M.incognita effectors that contained nuclear localization signals(NLSs).Combining the Burkholderia glumae-pEDV based screening system with subcellular localization,we identified six effectors that can effectively suppressed B.glumae-induced cell death in Nicotiana benthamiana.Moreover,we used qRT-PCR to quantify the expression levels of six effectors during different parasitic stages.and the results showed that the candidate effectors MiISE2 and MiISE10 had a high expression level in late parasitism stages,but they exhibited a very low expression level in early parasitism stages.Conversly,the candidate effectors MiISE6,MiISE5 MiISE9 and MiISE23 was upregulate in early sedentary stages,and then undergoing a dramatic reduction in the J3 parasitism stage.In this study,we focused on the study of MiISE6 and MiISE5,and speculated that they may play an important role during the initial establishment of the plant-nematode interaction.Hybridization in situ verified that MiISE6 and MiISE5 were expressed in the subventral esophageal glands.Yeast invertase secretion assay validated the function of the signal peptide harbored in MiISE6;and MiISE5 can be secreted to barley cells through infectious hyphae of Magnaporthe oryzae.The results of subcellular localization showed that the MiISE6 was localized in nucleus and MiISE5 was localized in cytoplasm.Transgenic Arabidopsis thaliana plants expressing MiISE6 and MiISE5 respectively became more susceptible to M.incognita.Inversely,the host-derived RNAi or TRV-mediated RNAi of MiISE6 and MiISE5 of the nematode can decrease its parasitism on host.Based on transcriptome analysis of the MiISE6 transgenic Arabidopsis samples and the wild-type samples,and integrating Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)enrichment analyses,we found that the respectively expression of the two effectors in Arabidopsis can suppress jasmonate signaling pathway.Our experimental results provide evidence to decipher the molecular mechanisms underlying the manipulation of host immune defense responses by plant parasitic nematodes,and transcriptome data also provide useful information for further study nematode-plant interactions.