Application of myxobacteria in preparation of medicine for predating and inhibiting plant pathogenic bacteria
The technical field is as follows:
the invention belongs to the fields of microbiology, biological control, natural product chemistry and pharmacology, and particularly relates to three strains of myxobacteria capable of predating and inhibiting plant pathogenic bacteria, and application of the myxobacteria in preparation of medicines for predating and inhibiting the plant pathogenic bacteria.
Background art:
plant diseases harm agricultural production and cause economic loss, and the prevention and treatment research of the plant diseases has important significance. The biological control technology has the advantages of no environmental pollution, good safety to people and other organisms, lasting control effect, no residue, strong specificity of killing diseases, easy coordination with other control measures, energy conservation and the like, thereby having wide development prospect. In the world, people pay more and more attention to environmental protection, the demand for 'pollution-free products' is continuously improved, and the biological control technology meeting the agricultural sustainable development requirement gradually becomes a research hotspot and an important direction.
To date, researchers have screened a large number of antagonistic strains with phytopathogen-inhibiting effects, including bacillus, streptomyces, pseudomonas, paenibacillus, trichoderma, and the like. The main biocontrol mechanism of the strains is that various antibiotic substances, toxins, bacteriocins, protein antibacterial substances and the like which antagonize pathogenic bacteria are generated in the growth and metabolism process, so that the effect of inhibiting or killing the pathogenic bacteria is achieved. Because the generation of secondary metabolites is greatly influenced by environmental factors, the antagonistic strains often have the problems of unstable control effect, poor durability and the like when applied in the field.
In biological control of insect pests or animal diseases, using natural enemy and predation relationships as main biocontrol mechanisms and research directions, a large number of successful cases have been reported. Some predators (microprodators) such as Lysobacter, Bdellovibrio, Bacteriovorax, Daptobacter, bacteriodes, and Myxococcales (myxobacterales) are also present in microorganisms.
In recent years, microbial predators and their predation have attracted increasing attention. The academia thought that the microbial predators are potential biocontrol bacteria. However, the potential of microbial predators for biological control is currently under investigation.
Myxobacteria (myxobacteria) can slide, and have a complex multicellular morphogenetic process, a unique intercellular signal transmission system and remarkable social behavior characteristics. Recently, it has been increasingly recognized that myxobacteria have greater advantages in biological control than pure microbial predators such as Bdellovibrio or Bacteriovorax because myxobacteria have multiple biocontrol mechanisms.
1. Myxobacteria are predators of microorganisms. Most myxobacteria can actively prey on other living microorganisms including bacteria, fungi, yeast, algae, etc. through unique wolf-pack behavior and gliding motion to meet their own nutritional needs. The predation range of the myxobacteria is quite wide, the preference of the myxobacteria to the predated bacteria is generally reflected in the level of a large classification unit such as phyla and class, physiological differentiation of the same bacteria is not considered, and the myxobacteria has important biological control significance and can possibly solve the control problems of large difference of certain pathogenic bacteria strains and the like.
2. Myxobacteria are the second largest antibiotic producing bacteria in prokaryotes, which are second to actinomycetes, can produce secondary metabolites with abundant and various varieties and novel structures, and have wide application potential in the aspects of drug development, biological pesticide, ecological management and the like. The research considers that microorganisms capable of producing secondary metabolites such as antibiotics are promising biological control factors, such as bacillus, streptomyces, pseudomonas and the like. It has recently been found that naturally active products secreted by myxobacteria often participate in their predation process as a predation tool or weapon.
3. The myxobacteria has strong stress resistance. Myxobacteria have two forms of vegetative cells and myxospores (myxospores), and can form myxospores with strong stress resistance under severe environmental conditions to resist external environments such as nutrient deficiency, acid and alkali, dryness, cold, heat, radiation and the like, so that the myxobacteria can survive in many extreme environments for a long time.
4. Myxobacteria favor substrates such as soil, rotten wood, bark, fecal from herbivorous mammals, and rotten lichen, and have good stability and competitiveness in these environments. Myxobacteria are indigenous bacteria widely distributed in soil, and have high diversity and abundance. A large number of researches show that whether the biocontrol bacteria has excellent competitiveness and colonization ability is the key of whether the biocontrol bacteria can stably exert the biocontrol effect for a long time. Therefore, the strong colonization ability and stress resistance of myxobacteria have great advantages for biological control.
5. Myxobacteria can control the number of other flora in the soil and maintain the micro-ecological balance of the soil. Studies have shown that myxobacteria are present in various habitats, affecting the colonial characteristics of other bacteria in the surroundings. As a microbial predator, myxobacteria, like predators in the animal food chain, can change dynamically as the number of predators changes. The soil microbial community structure is dynamically balanced. If this balance is broken, the number of pathogenic bacteria is increased dramatically and soil-borne diseases occur. Researches show that measures such as improving the soil microecological balance, improving the microbial community structure, improving the microbial diversity and the like have prevention and treatment effects on a plurality of plant diseases.
6. Myxobacteria are important participants in soil organism metabolism and play an important role in the material circulation of the earth's biosphere. Myxobacteria can secrete rich extracellular lyase, degrade biomass, macromolecular organic matters and the like in soil, increase available nutrients which can be absorbed by plants, promote crop growth, reduce crop diseases and insect pests, and contribute to development of ecological organic agriculture. Many researches have proved that measures for improving soil fertility by applying compost or organic fertilizer and the like have good control effect on plant diseases, and are one of the research directions for controlling plant diseases.
However, despite the important biocontrol potential, myxobacteria are currently under little research and use in biological control. In China, there is no report on the use of myxobacteria for biological control. In foreign countries, from the last 70 s, research on the prevention and control of plant pathogenic microorganisms by myxobacteria has been carried out successively.
In 1972, Hocking et al found that 3 strains of myxobacteria were able to lyse to varying degrees 6 phytopathogenic fungi belonging to the group consisting of Pythium intermedium, Rhizoctonia solani, Fusarium oxysporum and F.solani, respectively, in a plate experiment; in a pot experiment, the myxobacteria are inoculated in the culture soil to effectively reduce the damping-off and the fatality rate caused by the pathogenic fungi, and the myxobacteria are found to have good colonization effect in the culture soil. In 1984, Geyer et al plated basidiospores of Ustilago maydis on water agar plates, and induced and isolated from corn field soil two species capable of producing predatory plaques, one being ameba protozoa and the other being myxobacteria, which are also capable of controlling the amount of U.maydis in the cultivation soil. In 1984, Homma added pigment hyphae of Rhizoctonia solani and conidia of Cochliobolus miyabenus to soil, and 4 weeks later, it was found that the propagules of both fungi were lysed; under a scanning electron microscope, a large number of perforations and etches with different depths exist on the pathogenic fungus propagules; a myxobacterium Polyangium spp was isolated from hyphae and conidia of Cochliobolus miyabenus and confirmed to cause the above predation and lysis phenomena. In 2001, Taylor et al discovered that the myxobacteria Nannocystisexens inhibited the three Aspergillus fungi Aspergillus flavus and A. parasiticus when inoculated adjacently; when inoculated in overlapping manner, myxobacteria n.exedens can prey on and lyse spores, germinating spores, hyphae, sclerotia and the like of these fungi. In 2002, Bull et al found that 6 slime bacteria studied had lytic and predatory effects on 8 plant pathogenic fungi, Cylindrocarpon spp, Fusarium oxysporum f.sp.apii, Phytophthora capsici, Pyrhium ultmum, Rhizonia spp, Sclerotinia minor, Verticillium alboatrum and V.dahliae. In 2006, Bull et al reported that myxobacteria were used to prevent and treat Sclerotinia rot of lettuce caused by Sclerotinia minor. In 2011, Kim et al discovered that a strain of Myxococcus (Myxococcus) can control three pathogens, i.e., Borrytis cinerea, Colletotrichum acutatum and Pyricularia grisea, by utilizing dual mechanisms of self-predation and antagonism of an active product of the Myxococcus; in a pot experiment, the prevention and treatment effect of the myxobacteria on pepper anthracnose is obviously better than that of a fungicide dithianon. In 2015, Dahm et al isolated 30 myxobacteria from forest soil and tested their control effect on forest major disease fungi, and found that these myxobacteria lyse and inhibit 4 common forest disease fungi, Rhizoctonia solani, Fusarium oxysporum, F.culmorum, and Cylindrocarpon destructans; potting experiments show that some of the myxobacteria can protect seedlings from being damaged by R.solani, and the myxobacteria also prove that the myxobacteria have good colonization capacity in potting soil.
At present, few studies on the biological control effect of myxobacteria are conducted at home and abroad, and the above reports basically cover all publicly published papers. It can be seen that some myxobacteria have predation and inhibition effects on various plant pathogenic fungi, and also show control effects on plant diseases caused by these pathogenic fungi. In addition, myxobacteria, a soil indigenous bacterium with strong stress resistance, shows good colonization ability when used in soil. At present, research on preventing and treating plant diseases by myxobacteria mainly focuses on the aspect of plant pathogenic fungi. This is because fungi are the most common phytopathogenic microorganisms, and fungal diseases account for approximately 70-80% of plant diseases. In fact, myxobacteria have better predation and antagonism effects on bacteria. Therefore, the potential of myxobacteria in controlling plant bacterial diseases is expected, and related research needs to be strengthened urgently.
The invention content is as follows:
the invention provides application of three myxobacteria Myxococcus sp.e-3-1, Polyangium sp.8# -3 and Cystobacter sp.XJ9-1 in preparation of medicines for predating and inhibiting plant pathogenic bacteria.
The myxobacteria Myxococcus sp.e-3-1 is preserved in Guangdong province microorganism strain preservation center (five-storied building of laboratory building of Paris Microbiol institute of Centraalbean, Fuzhou province, Mielian province, China) in 2016, 11, 25 days, and the preservation number is as follows: gdmccno. 60120.
The myxobacteria Polyangium sp.8# -3 is preserved in Guangdong province microbial strain preservation center (five-storied building of experimental building of microbial institute of hundred province, Fule, China, Guangzhou city) in 2016, 11, 25 days, and the preservation number is as follows: gdmccno. 60122.
The myxobacteria Cystobacter sp.XJ9-1 is preserved in Guangdong province microorganism strain preservation center (five-storied building of the laboratory building of the microbial institute of hundred province, the first furious middle way, Guangzhou, China) in 2016, 11, 25 days, and the preservation number is as follows: gdmccno. 60121.
Experiments show that myxobacteria Myxococcus sp.e-3-1, Polyangium sp.8# -3 and Cystobacter sp.XJ9-1 can prey on various plant pathogenic bacteria and can also produce active natural products for inhibiting Erwinia persicinum.
Therefore, the invention provides the application potential of Myxococcus sp.e-3-1, Polyangium sp.8# -3 and Cystobacter sp.XJ9-1 in the aspects of inhibiting Erwinia persiciniae and preventing and treating plant soft rot caused by the Erwinia persiciniae. (the three myxobacteria and natural products thereof are developed into biological pesticides for inhibiting erwinia persicinia and plant soft rot caused by the pathogenic bacteria).
The invention also provides application of Myxococcus sp.e-3-1, Polyangium sp.8# -3 and Cystobacter sp.XJ9-1 in preparation of a medicine for inhibiting Erwinia persicinum.
The myxobacteria Myxococcus sp.e-3-1, Polyangium sp.8# -3 and Cystobacterbsp.XJ9-1 can prey and crack various plant pathogenic bacteria on one hand, and can generate active natural products for inhibiting Erwinia persicinum on the other hand, thereby having important application value. The myxobacteria Myxococcus sp.e-3-1, Polyangium sp.8# -3 and Cystobacter sp.XJ9-1 can be applied to biological prevention and treatment, drug development and the like.
The myxobacteria Myxococcus sp.e-3-1 is preserved in Guangdong province microorganism strain preservation center (five-storied building of the laboratory building of the Ministry of the hundred provinces of the first furious middle way, Guangzhou, China) in 2016, 11, 25 days, and the preservation number is as follows: gdmccno. 60120.
The myxobacteria Polyangium sp.8# -3 is preserved in the Guangdong province microbial strain preservation center (five-storied building of the experimental building of the century-Bai province microbial institute of the first furious middle Lou, Guangzhou, China) in 2016, 11, 25 days, and the preservation number is as follows: gdmccno. 60122.
The myxobacteria Cystobacter sp.XJ9-1 is preserved in Guangdong province microbial strain preservation center (five-storied building of the Experimental building of the microbial institute of hundred province, the first furious middle way, Guangzhou, China) in 2016, 11, 25 days, and the preservation number is as follows: gdmccno. 60121.
Drawings
FIG. 1 is the predation effect of Myxococcus sp.e-3-1 on plant pathogenic bacteria;
FIG. 2 is the predation effect of Polyangium sp.8# -3 on plant pathogenic bacteria;
fig. 3 is a predation effect of cystobater sp.xj9-1 on plant pathogenic bacteria.
The specific implementation mode is as follows:
the following examples are further illustrative of the present invention and are not intended to be limiting thereof.
Example 1:
the myxobacteria Myxococcus sp.e-3-1 and Polyangium sp.8# -3 are from the saline-alkali soil of Aksu Xinjiang.
The myxobacteria Cystobacter sp.XJ9-1 is derived from original forest soil samples in national parks of a Vietnam Tan road.
Example 2:
respectively inoculating myxobacteria Myxococcus sp.e-3-1, Polyangium sp.8# -3, Cystobacter sp.XJ9-1 to CYE culture solution (10mM MOPS, 10g/L casein peptone, 5g/L yeast extract, 8mM MgSO 8. sup.M)4Water as solvent, pH 7.6), 150rpm, 30 ℃ for 3 days, followed by MMC buffer (10mM MOPS, 4mM MgSO 4)4,2mM CaCl2Solvent is water, pH 7.6) is diluted to 1X 1011cell/ml to obtain myxobacteria liquid.
Inoculating each plant pathogenic bacterium (Rhizobium radiobacter GIM1.274, Pseudomonas aeruginosa GIM 1.330, Acidovorax avenae JCM20985, Rhodococcus fascians NBRC 12155, Burkholderia cepacia GIM1.450, Curtobacterium flavicum GIM1.343, Erwinia persicina GIM 1.331, Arthrobacter ilicis JCM12267, Erwinia chrysophami GIMT 1.178, Pantoea stearothermophilus subsp. stearothermophilus LMG2715, Ralstonia solanacearum GIM 1.70, Rhizobacter 11587, Bacillus subtilis DSM 1718583, Escherichia coli JCM 21, Xanthomonas chrysis 8584, Xanthomonas oryzae # CM 3559, Xanthomonas sp # CM 3514, Xanthomonas sp # 8, Xanthomonas sp # 3, Xanthomonas sp # 1.7, Xanthomonas sp # 2, Xanthomonas sp, D2, and D3, D, E9And obtaining the plant pathogenic bacteria liquid by cell/mL. The phytopathogenic bacteria used in this test are shown in Table 1.
20 μ L of plant pathogenic bacteria was dropped on CFL solid medium (10mM MOPS, pH 7.6, 1mM KH)2PO4,8mM MgSO4,0.2g/L(NH4)2SO40.2g/L sodium citrate, 0.2g/L sodium pyruvate, 0.1g/L casein peptone, 15g/L agar, and water as a solvent), and after drying, dripping 1 μ L of myxobacteria ink mixed liquor (the ratio of the myxobacteria liquid to the ink is 2: 1 mix) and the edges of the two colonies were spaced about 3mm apart. The plates were incubated at 30 ℃ and predation was observed after 3, 5, 7, and 9 days. The results are shown in FIGS. 1, 2 and 3, and it can be seen from FIGS. 1 to 3 that Myxococcus sp.e-3-1 is capable of preying on Rhizobium radiobacter GIM1.274,pseudomonas syringae GIM 1.330, Acidovorax avenae JCM20985, Rhodococcus fascians NBRC 12155, Burkholderia cepacia GIM1.450, Curtobacterium flavicum GIM1.343, Erwinia persicina GIM 1.331, Arthrobacter ilicis JCM12267, Erwinia chrysogeni GIMT 1.178, Pantoea personalis subsp.stetii LMG2715, Ralstonia solanacearum GIM 1.70, Rhizobacter dauci DSM 11587, Sphingomonas suicides JCM 8521, Xanthomonas fasciata JCM 20466, Xanthomonas hydrophila JM 20466, Xanthomonas hydrophila JCM 1370.270, Streptomyces sporogenes CM 13714; polyangium sp.8# -3 is capable of preying on Rhizobium radiobacter GIM1.274, Pseudomonas syringae GIM 1.330, Acidovorax avenae subsp aveae JCM20985, Rhodococcus fascians NBRC 12155, Curtobacterium flavum GIM1.343, Arthrobacter ilicis JCM12267, Erwinia chrysogeni GIMT 1.178, Pantoea radiobacter subsp.stewartii LMG 5, Ralstonia solanacearum GIM 1.70, Rhizobacter davurici DSM 11587, Sphingomonus JCM 8521, Xanthomonas bacterium JCM 20466, Xanthomonas bacterium sp.17159, Streptomyces sporogenes JCM1370, Streptomyces sporogenes CM 271270; cystobacter sp.XJ9-1 is capable of preying on Rhizobium radiobacter GIM1.274, Pseudomonas syringae GIM 1.330, Acidovorax avenae subsp aveae JCM20985, Rhodococcus fascians NBRC 12155, Curtobacterium flavicum GIM1.343, Erwinia persicina GIM 1.331, Arthrobacter ilicis JCM12267, Erwinia chrysogeni GIMT 1.178, Pantoea stearothermophili subsp.stearothermophili LMG2715, Ralstoniana lacerum GIM 1.70, Rhizobacter daucus DSM 11587, Sphingomonus JCM 8521, Xanthomonas campestris JCM 84, Xanthomonas campestris JCM 3559, Corynebacterium parva CM1370, Corynebacterium parva CM 13714; .
TABLE 1 plant pathogenic bacteria and induced diseases
Example 2: study on inhibitory Effect of metabolites of myxobacteria on plant pathogenic bacteria (Erwinia persicinum)
Adding VY/2 culture medium (5g Angel active yeast, boiling in water for 10min, cooling, adding 1g MgSO4,1gCaCl2Adjusting pH to 7.4, diluting to 1L, sterilizing at high temperature and humidity, and adding 0.5mg vitamin B before use12) Inoculating Myxococcus sp.GIMe-3-1, Polyangium sp.8# -3 and Cystobacter sp.XJ9-1, culturing at 30 deg.C for 7d, centrifuging at 4000rpm, and collecting thallus and supernatant. Extracting the fermentation liquor with equal volume of ethyl acetate for 12h, and dissolving the extract with methanol after rotary evaporation of the extract to obtain the fermentation liquor extract. Soaking thallus in acetone, ultrasonic crushing, extracting with ethyl acetate for 12 hr, rotary evaporating the extractive solution, and dissolving the extract with methanol to obtain thallus crushing liquid extract. The extract of the fermentation broth and the extract of the disrupted cell broth were dissolved in methanol to concentrations of 50mg/mL and 100mg/mL, respectively. Inoculating plant pathogenic bacteria to NA liquid culture medium at 150rpm, and culturing at 30 deg.C to logarithmic phase. The plant pathogenic bacteria (Erwinia persicinum) solution in logarithmic phase is mixed with NA agar culture medium (liquid state) at about 50 ℃ according to the volume ratio of 1:100, and 20mL of the mixed solution is added into each plate after shaking up. A6 mm-diameter filter paper sheet to which 5. mu.L of fermentation broth extract solutions or cell disruption solution extract solutions of different concentrations had been added dropwise was attached to the plate. And (4) culturing at 37 ℃ for 24-36 h, and then determining the diameter of the inhibition zone. The inhibitory effect of the crude extracts of three myxobacteria on erwinia persicinis is shown in table 1.
TABLE 1 inhibition zone diameter of crude extracts of three myxobacteria against Erwinia persicae