The Lethal Effect And Action Mechanism Of Acids Compounds Against The Plant Parasitic Nematodes

The biological activities of acids compounds against nematodes were systematically studied to understand the structure-activity relationship and mechanism of compounds, understand the action mode and physiological changes of nematode, then reveal the molecular mechanism of nematode based on Meloidogyne incognita, Heterodera glycines and Ditylenchus destructor as the research objects. The results were summarized as follows:1. To make clear the activity of acids compounds against nematodes and speculate the activity groups was COO-.The acids compounds inhibited nematode’s life ability in different degrees. Formic acid, acetic acid, propionic acid and small molecular acid among the compounds had strong effect on nematode toxicity and the eggs hatch. Comparative the molecular structure and nematodes toxicity of compounds found that low molecular weight or small molecular volume compounds had stronger effect to nematodes but high molecular weight or macromolecular volume of compounds had weaker effect to nematodes. Compounds contains more acid groups COO- had stronger effect, such as oxalic acid. In addition CL-also had higher inhibitory ability. But many groups, benzene or other large groups in the compounds, appear lower inhibitory ability.2. To test the control effects of high active compounds in greenhouse.The results showed that, all the compounds could reduced nematode infection rate in different degrees. Inhibition rate reached over 70% against M. incognita and H. glycines after application formic acid and propionic acid. Acetic acid and oxalic acid also had higher control effect against M. incognita, but on the contrary to H. glycines. Citric acid and malic acid had no obvious effects to control the two kinds of nematodes. From the host plant growth situation, the plants grew well treated by oxalic acid, citric acid, malic acid and plants grew inhibited by formic acid, acetic acid, propionic acid. Moreover, there were less affected when plant seeds and seedlings treated by oxalic acid, citric acid and malic acid.3. To studied the action mode of the acids compounds preliminary. The results showed that nematode’s ability of living, movement, individual development, body fluids extravasation and forms changed greatly treated by acids compounds. Nematodes life force was decreased obviously, movement was restrained.Nematodes growth also greatly affected by acids, such as nematode’s length shortened, stylet and tail transparent area elongation. Meanwhile nematode fluid leakage intensified and appeared inclusions serious degradation, nematode’s body hollow and the body wall atrophy after treated by acids compounds.4. To confirm the influence of nematode physiological metabolism.The test revealed that nematode’s total sugar content, glycogen content, soluble protein content and cholinesterase activity appeared decline but glycerin and amino acids were on opposite treated by acid compounds.5. To cloned the 14-3-3 protein genes of M. incognita and H. glycines, and obtained the full-length sequence of H. glycines 14-3-3 gene for the first time.The full-length sequence of M. incognita and H. glycines 14-3-3 protein gene were cloned using RT-PCR and RACE technology, sequences span were 1525 bp and 1027 bp. Sequence analysis showed that M. incognita 14-3-3 gene contains one open reading framework, coding 261 amino acids. H. glycines 14-3-3 gene coded 251 amino acids. Both included 14-3-3 protein family conservative structure domain. Multiple sequence alignment analysis was once again proven 14-3-3 protein gene was highly conservative. Gene sub-cellular localization analysis showed 14-3-3 gene may be distributed in nematode’s cytoplasm, nucleus, cytoskeleton, mitochondria, golgi apparatus, endoplasmic reticulum and cell membrane.6. To analyzes the gene expression changes of H. glycines treated by acid compounds application high-throughput digital expression spectrum technique. And to confirm the relative amount of 14-3-3 protein gene expression changes through RT-PCR.Application high-throughput digital expression spectrum technique, all the gene expression of H. glycines were detected and compared with reference genes and genome, screened 968 differentially expressed genes, noted the gene characteristics such as the biological function, cell position and participation in biological processes and so on. In addition the result of RT-PCR indicated that the relative expression level increased of 14-3-3 protein gene,10.5 times than untreated nematode for the H. glycines.