Disclosure of Invention
The invention aims to provide a new application of thioether compound allyl propyl disulfide, and also aims to provide a biogenic bacteriostatic agent which can inhibit the release and swimming of phytophthora zoospores, the germination of phytophthora resting spores, the growth of hyphae and the cracking of phytophthora zoospores from the phytophthora spore development stage, reduce the latency of the phytophthora spores in soil and reduce the infection of the phytophthora to crops.
The thioether compound allyl propyl disulfide can be detected in garlic root secretion, root volatile matters and rhizosphere soil. In the prior art, research on bacteriostatic substances of sulfur-containing compounds in garlic is mainly carried out aiming at the bacteriostatic effect of the sulfur-containing compounds in the whole garlic, garlic cloves, volatile matters of garlic root systems, secretion or water leaching solution of the whole root systems.
In the research on the bacteriostatic effect of garlic single substances, such as dimethyl trisulfide (DMTS), diallyl disulfide (DADS), diallyl trisulfide (DATS) and the like, the research focuses on the inhibition research on the growth of the hyphae, and the research shows that when the concentration of DMTS, DADS and DATS is 1000 mug/mL, the inhibition rate on the growth of phytophthora hyphae reaches 100%.
The thioether compound allyl propyl disulfide provided by the invention not only acts on inhibition of phytophthora hyphae, but also has a remarkable inhibition effect in a phytophthora spore stage, and has a clear action mechanism, and the inhibition effect comprises inhibition of spore release of phytophthora sporangium, inhibition of zoophoresis of phytophthora zoospore, inhibition of phytophthora telorum germination, and promotion of lysis of phytophthora zoospore.
The structural formula of the thioether compound allyl propyl disulfide is shown in the specification
The molecular formula is: c
6H
12S
2. The invention finds application in the inhibition of phytophthora by allylpropyldisulfide or a preparation containing allylpropyldisulfide.
In a first aspect, the present invention provides the use of allyl propyl disulfide or a formulation containing it to inhibit the release of phytophthora zoospores, using the following experimental protocol, it was found that complete inhibition of phytophthora zoospores release can be achieved at allyl propyl disulfide concentrations of at least 100 μ g/mL.
The experimental scheme is as follows:
the preparation concentration is 1 multiplied by 104A strain/mL phytophthora capsici sporangia suspension;
② pipette 40. mu.L of zoospore suspension into the groove of the concave glass slide, and add 10. mu.L of 6 kinds of allyl propyl disulfide aqueous solutions with different concentrations so that the final concentrations of allyl propyl disulfide are 0. mu.g/mL, 10. mu.g/mL, 50. mu.g/mL, 100. mu.g/mL, 500. mu.g/mL and 1000. mu.g/mL, respectively. The concave slide was placed on the stage of a microscope, zoospores were found with a 4-fold objective lens, and observed with a 10-fold objective lens. Counting spore release rates of 0min, 20min and 40min, and calculating release inhibition rate. The release inhibition (%) was (control release rate-treatment release rate)/control release rate × 100%.
In a second aspect, the present invention provides the use of allyl propyl disulfide or a formulation containing it to inhibit the motility of phytophthora spores, the inhibitory effect of allyl propyl disulfide on phytophthora capsici zoospores being found to increase with increasing concentration of allyl propyl disulfide, using the following experimental protocol.
The experimental scheme is as follows:
the preparation concentration is 2 multiplied by 105The strain/mL of phytophthora capsici zoospore suspension;
absorbing 40 mu L of zoospore suspension into the groove of the concave glass slide by a liquid moving machine, and respectively adding 10 mu L of 6 kinds of allyl propyl disulfide aqueous solutions with different concentrations to ensure that the final concentrations of the allyl propyl disulfide are respectively 0 mu g/mL, 10 mu g/mL, 50 mu g/mL, 100 mu g/mL, 500 mu g/mL and 1000 mu g/mL;
thirdly, counting the stopping rate of the zoospores after the allyl propyl disulfide solution is added for 40min, and calculating the average value of the stopping rate. The cut-off rate (%). is the number of dormant spores/(number of dormant spores + number of zoospores) × 100%, i.e., the motility inhibition rate.
In a third aspect, the invention provides the use of allyl propyl disulfide or a preparation containing allyl propyl disulfide for inhibiting phytophthora root rot spore germination, and using the following experimental scheme, it is found that the inhibition of phytophthora root rot spore germination is significantly effective when the concentration of allyl propyl disulfide is at least 500 μ g/mL.
The experimental scheme is as follows:
the preparation concentration is 2 multiplied by 105Peronosporangium capsici suspension per mL;
pipetting 40 mu L of the suspension of the resting spores to the groove of the concave glass slide, respectively adding 10 mu L of 6 kinds of allyl propyl disulfide aqueous solutions with different concentrations (using a pre-vortex for 5s) to ensure that the final concentrations of the allyl propyl disulfide are 0 mu g/mL, 10 mu g/mL, 50 mu g/mL, 100 mu g/mL, 500 mu g/mL and 1000 mu g/mL respectively;
thirdly, counting the germination rate of the 6h of the aposporium and calculating the germination inhibition rate. The germination inhibition ratio (%) - (control germination ratio-treatment germination ratio)/control germination ratio × 100%.
In a fourth aspect, the present invention provides the use of allyl propyl disulfide or a formulation containing allyl propyl disulfide for inhibiting the growth of phytophthora hyphae, wherein the rate of inhibition of the growth of phytophthora hyphae by allyl propyl disulfide is found to increase with increasing concentration of allyl propyl disulfide by the following experimental protocol.
The experimental scheme is as follows:
firstly, diluting allyl propyl disulfide standard products into different concentrations by using methanol so as to ensure that the final concentrations of the allyl propyl disulfide are 0 mu g/mL, 10 mu g/mL, 50 mu g/mL, 100 mu g/mL, 500 mu g/mL and 1000 mu g/mL respectively;
② preparing 100ml liquid culture medium, pouring into a triangular conical flask;
③ adding 1ml of allyl propyl disulfide-methanol mixed solution with different concentrations into a triangular conical flask, adding only 1ml of methanol into a control group, and repeating each treatment for 3 times;
and fourthly, adding 6 phytophthora capsici cakes into each triangular conical flask, putting the conical flasks into a shaking table, culturing the conical flasks at 140rpm for 3d, filtering the conical flasks to remove liquid, wrapping hyphae with filter paper, drying the conical flasks, weighing the conical flasks, and calculating the hypha inhibition rate (%) (the weight of the control group hyphae-the weight of the treatment group hyphae)/the weight of the control group hyphae multiplied by 100 percent.
In a fifth aspect, the present invention provides the use of allyl propyl disulfide or a formulation containing allyl propyl disulfide for promoting the lysis of phytophthora natans spores, and using the following experimental protocol, it was found that the effect of promoting the lysis of phytophthora capsici zoospores is obtained at an allyl propyl disulfide concentration of at least 10 μ g/mL.
The experimental scheme is as follows:
the preparation concentration is 2 multiplied by 105The strain/mL of phytophthora capsici zoospore suspension;
absorbing 40 mu L of zoospore suspension into the groove of the concave glass slide by a liquid moving machine, and respectively adding 10 mu L of 6 kinds of allyl propyl disulfide aqueous solutions with different concentrations to ensure that the final concentrations of the allyl propyl disulfide are respectively 0 mu g/mL, 10 mu g/mL, 50 mu g/mL, 100 mu g/mL, 500 mu g/mL and 1000 mu g/mL;
standing for 140min, and counting the cracking rate. The cleavage ratio (%) (control group non-cleavage ratio-treatment group non-cleavage ratio)/control group non-cleavage ratio × 100%.
In a sixth aspect, the present invention provides the use of allyl propyl disulfide or a formulation containing it in the preparation of a chemical or biological agent for the inhibition of phytophthora. Based on the understanding of those skilled in the art, a pesticide for controlling pepper diseases, which contains allylpropyldisulfide.
The invention has the beneficial effects that:
the compound allyl propyl disulfide has an obvious inhibition effect in the whole infection process of phytophthora spores, particularly has an obvious inhibition effect on phytophthora zoospore germination and resting spore germination, and can remarkably promote phytophthora zoospore lysis. The compound allyl propyl disulfide is a biological source substance, can be obtained from garlic root volatile matters, rhizosphere soil volatile matters, root water immersion liquid and root secretion, can also be obtained by chemical synthesis, and has wide raw material sources.
Detailed Description
The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.
The compound allyl propyl disulfide is a biological source and can be obtained from volatile matters of garlic root systems, volatile matters of rhizosphere soil, root water immersion liquid and root secretion. The conventional method can be adopted in the collection and acquisition of garlic root system volatile matters, rhizosphere soil volatile matters and sulfur-containing substances in root system water extract and the detection method of a gas chromatography-mass spectrometer.
The referenced method is as follows:
(1) collection of garlic root volatiles
300g of fresh garlic roots were placed in a sealed sample chamber and connected to a Porapak Q80/100 column to create a sealed air circuit. And 3d, leaching the resin column by using normal hexane, collecting 5mL of leacheate, concentrating to 2mL by using a nitrogen blowing method, and enriching sulfur-containing compounds in volatile matters of the garlic root system into liquid. 2mL of n-hexane dissolved solution is placed in a 2mL brown sample bottle and stored at 4 ℃ in a sealed manner.
(2) Collection of garlic rhizosphere soil volatile matter
Collecting rhizosphere soil samples: collecting garlic rhizosphere soil to be detected, filling the garlic rhizosphere soil into a self-sealing bag, sealing the self-sealing bag, immediately putting the self-sealing bag into an ice box or a refrigerator, controlling the temperature to be about 4 ℃, and keeping the time from the end of sampling to the beginning of volatile matter detection to be not more than 24 hours;
collecting volatile matters of the soil to be detected: weighing 2kg of soil to be detected, dispersedly placing the soil into 10 glass culture dishes, placing 200g of soil into each culture dish, dispersedly placing the soil into a large glass jar, covering a glass cover, sealing a gap between the cover and a cylinder body by using a sealing film, and respectively connecting the top of the glass jar with a sample tube filled with adsorption resin and an emptying tube formed by sequentially connecting an empty sample tube, a rubber tube, a water-absorbing allochroic silicone tube and an activated carbon tube; and opening an air pump at the other end of the sample tube, collecting for 5d to enable sulfur-containing compounds in the soil to be detected to be fully volatilized and adsorbed on the adsorption resin in the sample tube, leaching the adsorption resin by using normal hexane, collecting 5mL of leacheate, blowing nitrogen to concentrate the leacheate into 2mL, putting 2mL of normal hexane solution into a 2mL brown sample bottle after passing through a 22 mu m filter membrane, and sealing and storing at 4 ℃.
(3) Collection of garlic root system water extract
Vertically inserting 500g fresh garlic into 500ml beaker, adding 150ml ddH2O, completely immersing the root system of the garlic into water, sealing the opening of the beaker by using a sealing film, and standing for 3 hours;
extraction: taking 100ml of garlic root extract as a sample, adding 200ml of ethyl acetate for extraction, standing for layering, pouring out an upper organic phase for later use, continuously adding 200ml of ethyl acetate into a lower aqueous phase for secondary extraction, standing to obtain an upper organic phase extract, mixing organic phases obtained by the two extractions, adding anhydrous sodium carbonate to remove water in the extract for later use;
thirdly, performing rotary evaporation on the extract liquor: opening a low-temperature cooling circulating pump to pre-cool to 4 ℃; adding the extract into a round-bottom flask, carrying out water bath at the temperature of 40-60 ℃, and carrying out rotary evaporation; when a small amount of liquid remains in the round-bottom flask, transferring the liquid into a heart-shaped bottle, performing rotary evaporation until the liquid is dried, dissolving the substances in the heart-shaped bottle by using n-hexane or ethanol, and performing constant volume to 2 ml. 2mL of n-hexane solution is filtered through a 22-micron filter membrane and then placed in a 2mL brown sample bottle, and the sample bottle is sealed and stored at 4 ℃; 2mL of n-hexane solution was placed in a 2mL cryopreservation tube and stored in a sealed state at 4 ℃.
The characteristic fragments of the sulfur-containing compounds have more than 80% of similarity in root exudates, and substances collected from garlic root volatile matters, rhizosphere soil volatile matters and root water leaching liquid need to be compared with standard substances of the sulfur-containing compounds. And detecting by adopting a gas chromatography-mass spectrometry combined method to determine whether the sample to be detected contains a sulfur-containing compound, so as to obtain a GC-MS spectrogram of the sample to be detected.
Identifying volatile matters of garlic root systems, volatile matters of rhizosphere soil and sulfur-containing compounds in root system water leaching liquid:
taking a standard substance of a sulfur-containing compound, taking normal hexane as a solvent, preparing standard substance solutions with the concentrations of 0 mu g/mL, 100 mu g/mL, 200 mu g/mL, 400 mu g/mL and 600 mu g/mL respectively, and storing the standard substance solutions in a brown sample injection bottle in a dark place for later use;
② the detection is carried out by gas chromatography-mass spectrometer (GCMS-QP2010 ultra, Shimadzu, Japan). GC conditions were as follows: SH-Rxi-5Sil MS column (30.0m 0.25mm 0.25 μm). The initial column temperature is 40 ℃, the temperature is raised to 80 ℃ at 3 ℃/min, then the temperature is raised to 260 ℃ at 5 ℃/min, and the temperature is kept for 30 min. The carrier gas is helium, the injection inlet temperature is 250 ℃, the injection amount is 2 mul, the injection mode is divided-flow injection, and the divided-flow ratio is 10: 1. MS conditions: EI ionization source, ion source temperature 230 ℃, interface temperature 250 ℃, scanning range m/z 35-500, acquisition mode Scan, and scanning interval 0.30 s. Volatile components were identified by NIST14s spectral library.
The phytophthora mycelium cake, sporangium suspension, zoospore suspension and telosporium suspension may be obtained through conventional process, including the following steps:
(1) test medium and hypha culture: carrot medium (carrot agar, CA) was prepared. Adding appropriate amount of water into a pan, adding sliced carrot, decocting for 40min, adding carrot juice and cooked carrot into a juicer, crushing, filtering with 2 layers of gauze, mixing the filtrate with carrot juice, and adding ddH2And (4) fixing the volume by using O. 200g carrot and 20g agar powder per 1L medium are required. Sterilizing with high pressure steam at 121 deg.C for 20min, cooling to 90 deg.C, pouring into 90mm plastic culture dish (15 ml each), cooling to room temperature, inoculating 7mm diameter fungus cake, and culturing in 25 deg.C dark incubator for 7 d.
(2) Preparation of sporangia suspension:
and scraping phytophthora capsici mycelia from the culture medium cultured for 7d by using a cover glass, and washing the scraped phytophthora capsici mycelia into a freezing tube blocked by a layer of gauze by using sterile water. Sporangial suspension concentrations were adjusted to 1X 10 using a blood-ball-plate counting plate4one/mL.
(3) Preparation of zoospore suspension:
15ml of sterilized ddH was added to the culture dish for 7d2O, placing in a refrigerator at 4 deg.C for cold stimulation for 30min, standing at 25 deg.C for 30min, releasing zoospores, counting with a blood counting plate, diluting to obtain 2 × 105pieces/mL zoospore suspension.
(4) Preparation of a suspension of resting spores:
15ml of sterilized ddH was added to the culture dish for 7d2O, placing in a refrigerator at 4 deg.C for cold stimulation for 30min, standing at 25 deg.C for 30min, releasing zoospores, counting with a blood counting plate, diluting to obtain 2 × 105pieces/mL zoospore suspension. Shaking with vortex instrument for 5min to make flagella of zoospore fall off, and converting zoospore into inactive spore, wherein the obtained liquid is inactive spore suspension.
Taking the water solutions of different concentrations of allyl propyl disulfide as examples, the effects of different concentrations of allyl propyl disulfide on the release of phytophthora zoospores, germination of resting spores, hyphal growth and zoospore lysis were measured respectively. The results of the experiments of examples 1-5 are shown in Table 1.
Example 1 Effect of allylpropyldisulfide on the Release of Phytophthora capsici Leonian spores
The preparation concentration is 1 multiplied by 104A strain/mL phytophthora capsici sporangia suspension;
② pipette 40. mu.L of zoospore suspension into the groove of the concave glass slide, and add 10. mu.L of 6 kinds of allyl propyl disulfide aqueous solutions with different concentrations so that the final concentrations of allyl propyl disulfide are 0. mu.g/mL, 10. mu.g/mL, 50. mu.g/mL, 100. mu.g/mL, 500. mu.g/mL and 1000. mu.g/mL, respectively. The concave slide was placed on the stage of a microscope, zoospores were found with a 4-fold objective lens, and observed with a 10-fold objective lens. Counting spore release rates of 0min, 20min and 40min, and calculating release inhibition rate. The release inhibition (%) was (control release rate-treatment release rate)/control release rate × 100%.
The experimental results show that:
the inhibition rate of the spore release of phytophthora capsici sporangium reaches 100% at the concentration of allyl propyl disulfide of 100 mu g/mL.
Example 2 Effect of allylpropyldisulfide on motility of Phytophthora capsici zoospores
The preparation concentration is 2 multiplied by 105The strain/mL of phytophthora capsici zoospore suspension;
absorbing 40 mu L of zoospore suspension into the groove of the concave glass slide by a liquid moving machine, and respectively adding 10 mu L of 6 kinds of allyl propyl disulfide aqueous solutions with different concentrations to ensure that the final concentrations of the allyl propyl disulfide are respectively 0 mu g/mL, 10 mu g/mL, 50 mu g/mL, 100 mu g/mL, 500 mu g/mL and 1000 mu g/mL;
thirdly, under a microscope, counting the stopping rate of the zoospores after 40min of adding the allyl propyl disulfide, and calculating the average value of the stopping rate. The cut-off rate (%). is the number of dormant spores/(number of dormant spores + number of zoospores) × 100%, i.e., the motility inhibition rate.
The experimental results show that:
the allyl propyl disulfide can obviously weaken the motility of phytophthora capsici zoospores, and the inhibition rate reaches 100% when the concentration of the allyl propyl disulfide is 1000 mu g/mL.
Example 3 Effect of allylpropyldisulfide on Germination of P.capsorum
The preparation concentration is 2 multiplied by 105A phytophthora capsici telarium suspension per mL;
pipetting 40 mu L of the suspension of the resting spores to the groove of the concave glass slide, adding 10 mu L of 6 kinds of allyl propyl disulfide aqueous solutions with different concentrations (vortex 5s before use) respectively to ensure that the final concentrations of the allyl propyl disulfide are 0 mu g/mL, 10 mu g/mL, 50 mu g/mL, 100 mu g/mL, 500 mu g/mL and 1000 mu g/mL respectively;
thirdly, counting the germination rates of the aposporium within 6h and 24h under a microscope, and calculating the germination inhibition rate. The germination inhibition ratio (%) - (control germination ratio-treatment germination ratio)/control germination ratio × 100%.
The experimental results show that:
the allyl propyl disulfide can inhibit the germination of phytophthora capsici, and the inhibition rate of the germination of the phytophthora capsici reaches 100% when the concentration of the allyl propyl disulfide is 1000 mu g/mL.
Example 4 Effect of allylpropyldisulfide on Phytophthora capsici hyphae
Firstly, preparing 100ml of liquid culture medium, and pouring the liquid culture medium into a triangular conical flask;
preparing allyl propyl disulfide solution with different concentrations by using methanol;
③ 1mL of the allyl propyl disulfide-methanol mixed solution with different concentrations was added to each of the triangular flasks so that the final concentrations of allyl propyl disulfide were 0. mu.g/mL, 10. mu.g/mL, 50. mu.g/mL, 100. mu.g/mL, 500. mu.g/mL, and 1000. mu.g/mL, respectively. Each treatment was repeated 3 times;
fourthly, adding 1ml of methanol into the triangular conical flask of the control group, and repeating for 3 times; and adding 6 Phytophthora capsici mycelium cakes into each triangular conical flask, putting into a shaking table, culturing for 3d at 140rpm, filtering to remove liquid, wrapping the mycelium with filter paper, drying, weighing, and calculating the mycelium inhibition rate. The hypha inhibition ratio (%) (control hypha weight-treated hypha weight)/control hypha weight × 100%.
The experimental results show that:
the allyl propyl disulfide can obviously inhibit the growth of phytophthora capsici mycelium, has obvious inhibition effect when the concentration is 100 mu g/mL, and reaches 100 percent when the concentration is 1000 mu g/mL.
Example 5 Effect of allylpropyldisulfide on Phomophthora capsici zoospore lysis
The preparation concentration is 2 multiplied by 105The strain/mL of phytophthora capsici zoospore suspension;
absorbing 40 mu L of zoospore suspension into the groove of the concave glass slide by a liquid moving machine, and respectively adding 10 mu L of 6 kinds of allyl propyl disulfide aqueous solutions with different concentrations to ensure that the final concentrations of the allyl propyl disulfide are respectively 0 mu g/mL, 10 mu g/mL, 50 mu g/mL, 100 mu g/mL, 500 mu g/mL and 1000 mu g/mL;
③ standing for 140min, and counting the cracking rate under a microscope, wherein the cracking rate (%) is (control non-cracking rate-treatment non-cracking rate)/control non-cracking rate is multiplied by 100%.
The experimental results show that:
allyl propyl disulfide has the effect of promoting the lysis of phytophthora capsici zoospores.
TABLE 1 Effect of different concentrations of allylpropyldisulfide on various stages of infestation by Phytophthora capsici
Comparative example 1 Effect of dipropyl disulfide on the Release of Phytophthora zoospores
Experiments were carried out for phytophthora zoospore release using dipropyl disulfide instead of allyl propyl disulfide, using the method used in example 1 above, and the comparative results are shown in table 2.
Comparative example 2 Effect of methyl propyl disulfide on the Release of Phytophthora zoospores
The release of phytophthora zoospores was carried out using the method used in example 1 above, using methylpropyl disulfide instead of allylpropyl disulfide, and the comparative results are shown in table 2.
Comparative example 3 Effect of dimethyl trisulfide on the Release of Phytophthora zoospores
Experiments were carried out for phytophthora zoospore release using dimethyl trisulfide instead of allylpropyldisulfide, using the method used in example 1 above, and the comparative results are shown in table 2.
TABLE 2 Effect of different thioethers on the zoospore release stage of Phytophthora
Comparative example 4 Effect of dipropyl disulfide on the motility of Phytophthora zoospores
Experiments using dipropyl disulfide instead of allyl propyl disulfide for motile phytophthora zoospores were conducted using the method used in example 2 above, and the experimental comparison results are shown in table 3.
Comparative example 5 Effect of methyl propyl disulfide on the motility of Phytophthora zoospores
Using the method used in example 2 above, methyl propyl disulfide was used instead of allyl propyl disulfide for the zoospore motility experiment of Phytophthora, and the experimental comparison results are shown in Table 3.
TABLE 3 Effect of different thioether Compounds on the zoospore motility stage of Phytophthora
Comparative example 6 Effect of dipropyl disulfide on Germination of Phytophthora aspergillum
Using the procedure used in example 3 above, dipropyl disulfide was used instead of allyl propyl disulfide for the germination experiments of Phytophthora aspergillus, and the comparative results are shown in Table 4.
Comparative example 7 Effect of methyl propyl disulfide on Germination of Phytophthora aspergillum
Using the procedure used in example 3 above, methyl propyl disulfide was used instead of allyl propyl disulfide for the experiments for germination of Phytophthora aspergillus, and the comparative results are shown in Table 4.
TABLE 4 Effect of different thioethers on the Germination stage of Phytophthora aspergillum
Although the invention has been described in detail hereinabove with respect to a general description and specific embodiments thereof, it will be apparent to those skilled in the art that modifications or improvements may be made thereto based on the invention. Accordingly, such modifications and improvements are intended to be within the scope of the invention as claimed.