Screening And Identification Of Endophytic Bacteria Inside Peanut Nodule And Toxic To Meilodogyne Hapla

The root knot nematode(Meloidogyne spp.), can cause agroforestry production the most serious nematode disease, caused by the annual crop yield losses greatly. The various host plants, in peanut, tomato, flower, such as oil of vegetables and horticultural crops such as serious harm. How to find safe and effective measures to prevent and control of the disease is currently international hot issues in the study. This paper mainly to harm of peanut in Liaoning Province Meloidogyne hapla as a target in screening the high virulence strains isolated from peanut nodule, and the identification, and preliminary testing of the peanut root knot nematode disease control effect. The results were as follows:1. Screening of endophytic bacteria from the root nodules of peanut. Collected from different habitats from 69 provinces and cities nationwide, vegetation cover and soil types of 495 soil samples, the peanut planting trap to obtain a variety of nodules, nodule endophytic bacteria population trapping were obtained after screening 637 nodules.19 strains of Rhizobium highly, endogenous Rhizobium were isolated 123 strains endophytic bacteria using agar dilution method, and then continue to screening and re screening of the root knot nematode two instar larvae of J2 have high toxicity of 11 strains of endophytic bacteria, hatching the fermentation broth on the northern root knot nematode have different degrees of inhibition, the inhibition rate of 27.7%-59.4%. Among them, strain Sneb1806 24 h after J2 treatment nematode mortality rate reached 91.4%, followed by strain Sneb1878, on the death rate of J2 reached 85.7%, the death rate of strain Sneb1872 could reach 83.9%, and its fermentation liquid on hatching oocysts of inhibition The highest rate can reach 59.4%.2. Identification of endophytic bacteria from the root nodules of peanut. By using 16S rDNA sequence homology analysis of population evolutionary relationships of 11 strains of highly virulent peanut nodule endophytic bacteria, found belong to 3 groups of 3.3 groups including pseudomonadaceae (Pseudomonadaceae), Huang Baodan (Xanthomonadace), fungi and rhizobia, (Rhizobiaceae), including Pseudomonas (Pseudomonadaceae) of 7 strains, accounting for 63.64% of the sequenced strains, is the dominant species. The Yellow single cell bacteria families (Xanthomonadace) and 3 strains of Rhizobium strains 1 strains (Rhizobiaceae), the number of two groups is not much, but fully reflects the diversity of peanut nodule endophytic bacteria and the community structure. Combined with the T vector cloning and sequencing results of bacterial morphology and physiological and biochemical characteristics and 16S rDNA gene sequence, the highly virulent strains Sneb1766, Sneb1777 and Sneb1872 according to the system identification, to determine the Sneb1766 strain of goat root Nodule bacteria (Rhizobium galegae) and strain Sneb1777 argyrophil oligo oxygen single cell bacteria (Stenotrophomonas rhizophila), and Sneb1872 strain and fluorescent reaction Monteggia Pseudomonas bacteria(Pseudomonas mandelii).3. Preliminary study on the control of peanut root knot nematode disease by endophytic bacteria. The greenhouse pot experiment using bacteria fermentation liquid coating susceptible cultivar Baisha 1016 seeds, inhibition of nematode infection test of 11 strains of highly virulent strains of Meloidogyne hapla. The results showed that, compared with the control treatment without wiring of insects,5 strains of endophytic bacteria can significantly inhibit the northern root knot nematode infection on peanut and the inhibition rate was more than 35%, in which the inhibitory effect of strain Sneb1777 showed the most obvious reached 50.15%, vigorous plant growth, photosynthetic rate increased, and the fresh weight and dry weight were significantly higher than the control, a significant difference compared with the control. Secondly, the strains of peanut peanut root root Sneb1766 fermentation liquid coating developed, relatively strong growth to the north, inhibition of root knot nematode Infecting Peanut rate reached 35.05%, the growth status was significantly better than the control, the photosynthetic rate increased significantly, increased the host plants on the accumulation of organic matter effectively, make the Peanut fresh weight and dry weight increased significantly, speculation is with nematicidal activity of bacteria to kill the fermentation liquid through contact with plant roots penetrated into the interior of the plant, as the plant bacteria group part, induced host resistance to the plant itself, the on the northern root knot nematode infested with a certain inhibitory effect, at the same time, the host plants of certain metabolic pathways and traits.