| Root knot nematode disease is one of difficult and severely harmful diseases in protected tomato cultivation.It will lead to a substantial decline in tomato production,even cease in severe cases.Because chemical control has many harms to the environment and human health,the use of plant-derived of biological control technology have become a new research hotspot.Earlier studies found that adding Jerusalem artichoke（Helianthus tuberosus L.）stalks to the soil can significantly reduce the occurrence of tomato root knot nematode disease.There were differences in the mitigation effect of different Jerusalem artichoke cv.and there was a phenomenon that inhibited the growth of tomatoes.But the mechanism of action was still unclear.The Jerusalem artichoke germplasm resource-‘J13’,which had a significant inhibitory effect on tomato root knot nematode disease that selected in the previous stage of this study,was used as the test material.In vitro experiments were conducted to compare the inhibitory effects of different parts of the plant extracts on Meloidogyne incognita.And used GC-MS technology to analyze the compound composition of different parts of the plant extracts;it has been screened out that the parts of plant extracts and its added concentrations that can reduce root knot nematode disease and do not affect the growth of continuous cropping tomatoes by pot experiment.It was clarified that the effects of the addition of the Jerusalem artichoke extracts on the related indicators of resistance by continuous cropping tomatoes,the occurrence of the root knot nematode disease and the soil microbial.The main findings are as follows:（1）The extracts of different parts of the Jerusalem artichoke can significantly inhibit M.incognita,but different parts have different inhibitory effects on the egg hatching and the juveniles（J2s）of M.incognita;Jerusalem artichoke leaf extracts had a better significant inhibitory effect on the egg hatching and the J2s of M.incognita than the tuber extracts and the stem extracts,and the tuber extracts were significantly better than the stem extracts.（2）Using GC-MS to analysis of different parts of Jerusalem artichoke extracts showed that 60kinds of compounds can be detected in the different parts of Jerusalem artichoke extracts.The types and contents of the compounds detected in the extracts of different parts were different.The most species of compounds detected in leaf extracts（containing 40 species）and the highest total compound concentration（peak area 1.84×109）.Correlation analysis between the detected compounds and the adjusted mortality of the J2s of M.incognita revealed that the types and concentrations of compounds were different for different parts of the Jerusalem artichoke extracts versus the adjusted mortality of the J2s of M.incognita there is a correlation.The most species（20species）and the highest content（7.51×108）of compound in Jerusalem artichoke leaf extracts of the corrected adjusted mortality of the J2s of M.incognita versus Jerusalem artichoke extracts were positively correlated,higher than stem and tuber extracts.It accounted for 40.76%of the compounds detected in leaf extracts.（3）Adding different concentrations of Jerusalem artichoke leaf extracts to soil can significantly alleviate the occurrence of tomato root knot nematode disease,but high concentration treatment inhibited the growth of continuous cropping tomatoes.After comprehensive comparison,it was determined that the 1%addition concentration of leaf extracts significantly inhibited the occurrence of tomato root knot nematode disease without affecting tomato growth.（4）The continuous cropping tomato added with the Jerusalem artichoke leaf extracts significantly increased the activities of root defense enzymes POD,PPO and PAL after inoculation with M.incognita,significantly increased the content of total phenols and lignin,and decreased the content of MDA.（5）High-throughput sequencing analysis of the continuous cropping tomatoes rhizosphere soil added with Jerusalem artichoke leaf extracts showed that adding Jerusalem artichoke leaf extracts significantly changed the structure of the microbial community.The Jerusalem artichoke leaf extracts increased the abundance of fungi,and when sampling on the 60 day,it significantly increased the diversity of soil fungi.Correlation analysis of soil microorganisms and soil population density found that the bacteria OTU2631（Bacillus）,OTU2277（Bacillus）and fungal OTU994（Mortierella）have significantly positive correlation with soil population density.And the addition of Jerusalem artichoke leaf extracts reduced the relative abundance of them.In summary,Jerusalem artichoke leaf extract contains the highest types and contents of compounds,and the most species and the highest content of compound in Jerusalem artichoke leaf extracts of the corrected adjusted mortality of the J2s of M.incognita versus Jerusalem artichoke extracts were positively correlated,making it the best inhibitory effect on M incognita.The 1%addition concentration while significantly inhibited the occurrence of tomato root knot nematode disease without affecting the growth of continuous cropping tomatoes,and it significantly improved the resistance of continuous cropping tomatoes and changed the community structure of soil microorganisms. |
