Lactobacillus casei capable of inhibiting activity of Chromium streptosporum and application of lactobacillus casei in green pepper storage

Abstract

The invention discloses a lactobacillus casei strain capable of inhibiting activity of Chromarospora sp. And application of the lactobacillus casei strain in green pepper storage. The invention provides lactobacillus casei GHY-4, and the preservation registration number of the lactobacillus casei GHY-4 is CGMCC (China General Microbiological Culture Collection Center) No.31925. Furthermore, the invention provides a microbial agent of the lactobacillus casei GHY-4. The invention also protects the application of the lactobacillus casei GHY-4 or the microbial inoculum in inhibition of alternaria alternata. The invention also protects the application of the lactobacillus casei GHY-4 or the microbial inoculum in fresh keeping of green peppers. The method can be used for fresh keeping of the green peppers and has application and popularization values for the green pepper industry.

Description

Technical Field

[0001] The invention belongs to the field of biotechnology and relates to a strain of Lactobacillus casei with the activity of inhibiting Alternaria chromospora and application thereof in green pepper storage. Background Art

[0002] Green peppers have high nutritional value and are a popular vegetable in China. Every year, a large number of fresh green peppers are transported from one region to another. The rot caused by infectious diseases after the harvest of green peppers accounts for about 50%-90% of the total loss. There are many types of infectious diseases that cause a large amount of fruit rot during the storage of green peppers. Some diseases not only cause a large amount of infection and harm to the growth period of green pepper fruits, but also have a stronger ability to infect green peppers during the storage period and a higher incidence rate. Green pepper black spot is a disease that is mainly caused by Alternaria alternata and is more harmful to green peppers. Its symptoms are mainly manifested by the initial appearance of small round, slightly depressed spots at the infection site, and then the spots rapidly expand into depressed lesions. Gray to black mold can form at the lesions. At the same time, the inner wall of the fruit is infected by mold, and the serious rot of the fruit during transportation and storage is more obvious. How to extend the storage and sales period of green peppers and reduce post-harvest losses through appropriate post-harvest processing technology is a problem that needs to be solved.

[0003] At present, the preservation technology of green pepper is mainly based on chemical preservatives. Common chemical preservatives currently used in fruits and vegetables include ClO2, 1-methylcyclopropane (1-MCP) and salicylic acid (SA). However, the continuous use of chemical preservatives will cause pathogens to develop resistance, environmental pollution and residues in agricultural products that endanger health. Physical antibacterial preservation technology mainly includes heat treatment, low temperature storage, modified atmosphere packaging and irradiation storage. Although physical antibacterial preservation technology can avoid the risk of harm caused by chemical antibacterial preservation, low temperature storage, modified atmosphere storage, heat treatment and other physical preservation technologies have the disadvantages of high energy consumption, high equipment investment and low applicability, and there are certain limitations in use. Biological antibacterial preservation technology has the characteristics of strong targeting, low preparation cost, wide source channels, small regional differences, less pollution, low resistance and toxic and side effects, and is considered to be a sustainable, safe and environmentally friendly modern antibacterial preservation technology. Exploring new and highly efficient antagonistic bacteria has important theoretical and practical significance. It can also accelerate the commercialization process of fruit microbial control and is of great significance for promoting the rapid and healthy development of the vegetable industry. Summary of the invention

[0004] The invention aims to provide a Lactobacillus casei strain having the activity of inhibiting Alternaria chromospora and application of the strain in green pepper storage.

[0005] The present invention provides Lactobacillus casei ( lactobacillus casei )GHY-4.

[0006] Lactobacillus casei ( Lactobacillus casei ) GHY-4 was deposited on September 10, 2024 in the General Microbiology Center of China Microorganism Culture Collection (referred to as CGMCC, address: No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences), with the deposit registration number CGMCC No.31925.

[0007] Furthermore, the present invention provides a bacterial agent of Lactobacillus casei GHY-4.

[0008] Specifically, the bacterial agent is a liquid bacterial agent.

[0009] The active ingredient provided by the bacterial agent is Lactobacillus casei GHY-4.

[0010] In the bacterial agent, the content of Lactobacillus casei GHY-4 is 1×10 6 cfu / mL-1×10 10 cfu / ml.

[0011] Specifically, the preparation method of the bacterial agent is as follows: Lactobacillus casei GHY-4 is inoculated into MRS liquid culture medium, and cultured at 30°C and 150rpm with shaking until the bacterial concentration reaches 1×10 10 cfu / mL.

[0012] Specifically, the preparation method of the bacterial agent is as follows: Lactobacillus casei GHY-4 is inoculated into MRS liquid culture medium, and cultured at 30°C and 150rpm with shaking until the bacterial concentration reaches 1×10 6 cfu / mL.

[0013] The invention also protects the use of Lactobacillus casei GHY-4 or the bacterial agent in inhibiting Alternaria alternata.

[0014] The invention also protects the use of Lactobacillus casei GHY-4 or the bacterial agent in preparing an Alternaria alternata inhibitor.

[0015] The invention also protects the use of Lactobacillus casei GHY-4 or the bacterial agent in green pepper preservation.

[0016] The invention also protects the use of Lactobacillus casei GHY-4 or the bacterial agent in preparing a green pepper preservative.

[0017] The present invention also protects the use of Lactobacillus casei GHY-4 or the bacterial agent, which is any one of the following (a) to (i): (a) Inhibit the rot of green pepper fruit; (b) delaying the ripening process of green pepper fruits after they are picked; (c) delaying the loss of firmness of green pepper fruits after picking; (d) inhibiting the increase in cell membrane permeability after picking of green pepper fruits; (e) Reduce the respiration rate of green pepper fruits; (f) increasing the soluble solids content of green pepper fruit; (g) inhibiting the degradation of titratable acid in green pepper fruit; (h) increasing the ascorbic acid content of green pepper fruit; (i) Increase the chlorophyll content of green pepper fruits.

[0018] The present invention also protects the use of Lactobacillus casei GHY-4 or the bacterial agent in preparing products; The present invention also protects a product, which comprises Lactobacillus casei GHY-4 or the bacterial agent.

[0019] Any of the above products is a reagent or a kit.

[0020] Any of the above products is an Alternaria inhibitor.

[0021] Any of the above products is a green pepper preservative.

[0022] The use of the product is any of the following (a) to (i): (a) Inhibit the rot of green pepper fruit; (b) delaying the ripening process of green pepper fruits after they are picked; (c) delaying the loss of firmness of green pepper fruits after picking; (d) inhibiting the increase in cell membrane permeability after picking of green pepper fruits; (e) Reduce the respiration rate of green pepper fruits; (f) increasing the soluble solids content of green pepper fruit; (g) inhibiting the degradation of titratable acid in green pepper fruit; (h) increasing the ascorbic acid content of green pepper fruit; (i) Increase the chlorophyll content of green pepper fruits.

[0023] Specifically, any one of the above Alternaria is Alternaria viticola.

[0024] Exemplarily, any of the green peppers mentioned above is a yellow-skinned pointed pepper.

[0025] The invention provides a new Lactobacillus casei strain, which has an antibacterial effect on Alternaria alternata, and after soaking green pepper fruits with the bacterial liquid of the strain, the ripening process of the green pepper fruits can be delayed and the decay thereof can be inhibited or delayed. The invention can be used for green pepper preservation and has application and promotion value for the green pepper industry.

[0026] Collection Instructions Bacteria name: Lactobacillus casei Latin name: Lactobacillus casei Classification name: Lactobacillus casei ( Lactobacillus casei ) Strain ID: GHY-4 Depository: China National Microbiological Culture Collection Administration General Microbiology Center Abbreviation of depository unit: CGMCC Address: No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing Storage date: September 10, 2024 CGMCC Registration Number: CGMCC No.31925 BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a morphological photograph of Lactobacillus casei GHY-4 in Example 1.

[0028] Figure 2 This is a photo of the antibacterial test of Lactobacillus casei GHY-4 against Alternaria alternata in Example 2.

[0029] Figure 3 These are exemplary photos of green peppers at various sampling time points in Example 3.

[0030] Figure 4 This is the statistical result of the decay rate in Example 3.

[0031] Figure 5 This is the hardness statistical result in Example 3.

[0032] Figure 6 This is the statistical result of cell membrane permeability in Example 3.

[0033] Figure 7 This is the statistical result of the respiratory intensity in Example 3.

[0034] Figure 8 This is the statistical result of the soluble solid content in Example 3.

[0035] Fig. 9 The titratable acid content in Example 3 is statistically analyzed.

[0036] Fig.10 This is the statistical result of VC content in Example 3.

[0037] Fig.11 This is the statistical result of the chlorophyll content in Example 3. DETAILED DESCRIPTION

[0038] The present invention is further described in detail below in conjunction with specific embodiments, and the examples provided are only for illustrating the present invention, rather than for limiting the scope of the present invention. The examples provided below can be used as a guide for further improvements by those of ordinary skill in the art, and do not constitute a limitation of the present invention in any way.

[0039] The experimental methods in the following examples, unless otherwise specified, are conventional methods, and are carried out according to the techniques or conditions described in the literature in this field or according to the product instructions. The materials, reagents, etc. used in the following examples, unless otherwise specified, can all be obtained from commercial sources. Unless otherwise specified, the quantitative tests in the following examples are set up for three repeated experiments, and the results are averaged. Excel 2013, SPSS 26.0 and Hiplot software were used to organize, analyze and plot the data. When performing variance analysis and multiple significant difference analysis, p < 0.05 indicates significant differences. The Alternaria used in Example 2 is Alternaria viticola (China Agricultural Microbial Culture Collection Management Center, strain number ACCC 36134).

[0040] MRS liquid culture medium (pH 6.2±0.2): each liter contains 10.0g of peptone, 5.0g of beef extract powder, 4.0g of yeast extract powder, 20.0g of glucose, 1.0ml of Tween-80, 2.0g of dipotassium hydrogen phosphate, 5.0g of sodium acetate, 2.0g of triammonium citrate, 15.0g of agar, 0.2g of MgSO4•7H2O, 0.05g of MnSO4•4H2O, and the balance is distilled water.

[0041] Example 1: Isolation, identification and preservation of Lactobacillus casei GHY-4 Strain GHY-4 was screened from traditional Gansu Jiangshui.

[0042] Morphological characteristics of strain GHY-4 (see Figure 1 ): Round-ended straight rods, about 0.85μm×4.1μm, single; surface colony diameter is about 2.4mm, raised, round, smooth, dense, white in color.

[0043] Physiological and biochemical characteristics of strain GHY-4: Gram-positive, lactic acid producing.

[0044] The genomic DNA of strain GHY-4 was extracted, and PCR amplification was performed using a primer pair consisting of primer 27F (5'-AGAGTTTGATCCTGGCTCAG-3', SEQ ID NO: 2) and primer 1492R (5'-TACGGCTACCTTGTTACGACTT-3', SEQ ID NO: 3), and then the amplified product was recovered and sequenced. Primer 27F and primer 1492R are universal primers targeting the coding gene of 16S rRNA. The sequencing result is shown in SEQ ID NO: 1. The sequencing results were compared for homology at NCBI.

[0045] Based on the above morphological characteristics, physiological and biochemical characteristics and molecular identification results, strain GHY-4 belongs to Lactobacillus casei and is named Lactobacillus casei GHY-4.

[0046] Lactobacillus casei ( Lactobacillus casei ) GHY-4 was deposited on September 10, 2024 in the General Microbiology Center of China Microorganism Culture Collection (referred to as CGMCC, address: No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences), with the deposit registration number CGMCC No.31925.

[0047] Example 2: In vitro inhibition evaluation of Lactobacillus casei GHY-4 against Alternaria alternata 1. Preparation of GHY-4 bacterial solution The activated Lactobacillus casei GHY-4 was inoculated into MRS liquid medium and cultured at 30°C and 150 rpm until the bacterial concentration reached 1×10 10 cfu / mL, which is the GHY-4 bacterial solution.

[0048] 2. Detection of the inhibitory effect of Lactobacillus casei GHY-4 on Alternaria 1. Pick a ring of Alternaria colonies, transfer to 10 ml of physiological saline and shake for 2 minutes, then filter through 400 mesh gauze to remove spores and collect the filtrate (the content of Alternaria in the filtrate was 8×10 5 cfu / ml), spread on LB solid medium plates, 100µl of filtrate / plate is called 100µl plate, and 200µl of filtrate / plate is called 200µl plate.

[0049] 2. Group processing: 100µl test group: Use an inoculation loop to dip the GHY-4 bacterial solution prepared in step 1, streak it on a 100µl plate (2µl bacterial solution / plate), and then culture at 30℃ for 48h.

[0050] 200µl test group: Use an inoculation loop to dip the GHY-4 bacterial solution prepared in step 1, streak it on a 200µl plate (2µl bacterial solution / plate), and then culture at 30℃ for 48h.

[0051] CK group: 100 µl of the plate without any treatment was taken and cultured at 30°C for 48 h.

[0052] Three replicates were performed with consistent results. Figure 2 It can be clearly seen that Lactobacillus casei GHY-4 can effectively inhibit the growth of Alternaria alternata. As the amount of Alternaria alternata added increases, the inhibitory effect of Lactobacillus casei GHY-4 on Alternaria alternata weakens.

[0053] Example 3: Application of Lactobacillus casei GHY-4 in green pepper preservation The variety of green pepper fruit used is yellow-skinned sharp pepper ( Capsicum annuum L.‌) was purchased from Shen County, Liaocheng, Shandong. All fruits were transported to the laboratory in just 24 hours, and were transported in a cold chain throughout the process. After the fruits arrived at the laboratory, they were left to stand for 12 hours before the test. The test selected green pepper fruits of uniform size, without mechanical damage on the surface, and without pests and diseases.

[0054] 1. Preparation of GHY-4 bacterial solution The activated Lactobacillus casei GHY-4 was inoculated into MRS liquid medium and cultured at 30°C and 150 rpm until the bacterial concentration reached 1×10 6 cfu / mL, which is the GHY-4 bacterial solution.

[0055] 2. Group Processing Take green pepper fruits, divide them into two groups, and treat them as follows: Experimental group (GHY-4 group): 300 green pepper fruits were soaked in the GHY-4 bacterial solution for 15 seconds, then taken out and drained until no water dripped, and then laid flat in a cardboard box with grids (one green pepper fruit was placed in each grid).

[0056] Control group (CK group): 300 green pepper fruits were soaked in sterile water for 15 seconds, then taken out and drained until no water dripped, and then laid flat in a cardboard box with grids (one green pepper fruit was placed in each grid).

[0057] Storage conditions: humidity 80%±0.5%, temperature 25±1℃.

[0058] Four sampling time points were set, namely, time 0, 4 days, 8 days, and 12 days after storage.

[0059] 3. Evaluation of preservation effect 1. Impact on decay rate Green peppers are prone to water loss and rot after harvest, which leads to a decline in fruit quality and affects their edible value and commercial value. Sampling was performed at four sampling time points, and 10 samples were randomly selected from each group each time to test the fruit corruption rate.

[0060] Rot rate (%) = number of rotten green peppers ÷ total number of green peppers × 100%.

[0061] See the exemplary photos of green peppers at various sampling time points. Figure 3 The rot rate statistics are shown in Figure 4 Compared with the CK group, the fruit rot rate of the GHY-4 group was significantly lower (p < 0.05). During the entire storage period, the rot rate of green peppers in the GHY-4 group remained at a low level, which was due to the fact that Lactobacillus casei GHY-4 could effectively inhibit the massive reproduction of pathogenic bacteria in green peppers.

[0062] 2. Impact on color The L* value indicates the brightness of the fruit. The a* value indicates the red-green value, and a negative value to a positive value indicates that the color of the fruit skin changes from green to red or yellow. The b* value indicates the yellow-blue value, and a negative value to a positive value indicates that the color of the fruit skin changes from blue to yellow.

[0063] Sampling was performed at four sampling time points, and 10 fruits were randomly selected from each group each time. The color parameters L*, a* and b* of the fruits were measured using a colorimeter, and the L*, a* and b* values ​​were recorded.

[0064] The results are shown in Table 1. The a* value of the green peppers in the GHY-4 group was lower than that in the CK group, indicating that the Lactobacillus casei GHY-4 treatment can better maintain the green color of the green peppers during postharvest storage. Compared with the green peppers in the CK group, the L* change range of the green peppers in the GHY-4 group was smaller, indicating that the Lactobacillus casei GHY-4 treatment can better maintain the fruit brightness of the green peppers during postharvest storage. The b* value of the green peppers in the GHY-4 group was significantly lower than that in the CK group (P < 0.05). The results showed that the Lactobacillus casei GHY-4 treatment can better maintain the color quality and color of the green peppers.

[0065]

[0066] 3. Impact on hardness Hardness can judge the texture of the fruit and is the main indicator of the fruit's storage properties and storage effect. As the fruit ages, the various quality indicators of the fruit will also decline. For example, the deterioration of the quality of vegetables after harvest is often accompanied by the softening of the fruit. When the hardness decreases, the fruit will be bruised when it encounters mechanical impact or compression, and the fruit will then become moldy and rot.

[0067] Samples were taken at four sampling time points, and 10 fruits were randomly selected from each group each time. The fruit firmness was measured using a texture analyzer.

[0068] Hardness statistics are shown in Figure 5 The hardness of green peppers in the GHY-4 group was significantly higher than that in the CK group (p < 0.05). This shows that Lactobacillus casei GHY-4 treatment can maintain a high hardness of green peppers during postharvest storage, thereby maintaining the storage quality of green peppers and extending the shelf life.

[0069] 4. Effect on cell membrane permeability The cell membrane permeability of fruit tissue reflects the integrity and aging degree of tissue cell membrane.

[0070] Take samples from the experimental group and the control group at four sampling time points. Weigh 3g of fruit, cut into 1mm thick slices, dilute to 25mL with deionized water, shake at 110rpm for 30min (the conductivity measured at this time is conductivity P1), then boil for 10min and cool quickly, add deionized water to 25mL (the conductivity measured at this time is conductivity P2). Measure the conductivity of deionized water, which is conductivity P0.

[0071] Calculate the cell membrane permeability (P).

[0072]

[0073] The statistical results of cell membrane permeability are shown in Figure 6 The cell membrane permeability of green peppers in the GHY-4 group was significantly lower than that in the CK group (p < 0.05), indicating that Lactobacillus casei GHY-4 treatment can effectively maintain the integrity of the cell membrane of green peppers, protect the cell tissue structure from damage, and reduce the permeability of the fruit membrane.

[0074] 5. Impact on breathing intensity Changes in respiration intensity are one of the important signs of ripening of fruits and vegetables. The higher the respiration intensity, the faster the fruit metabolism and the faster it decays. Green pepper is a typical non-climacteric respiration fruit, and its respiration rate tends to decrease with the increase of storage time.

[0075] Take samples from the experimental group and the control group at 4 sampling time points (10 samples from each group at each time point). After weighing 10 fruits, place them in a 2L sealed glass container for 20 minutes, and collect 1ml of headspace gas in the glass container, which is the test gas. Use gas chromatography to detect the CO2 content in the test gas, and calculate the CO2 production (in mg) per unit fresh weight (i.e. per kilogram of fresh weight) of fruits in the glass container per unit time (i.e. per hour), which is the respiration intensity. The unit of respiration intensity is mg / (kg·h).

[0076] The results of respiratory intensity statistics are shown in Figure 7Compared with the green peppers in the CK group, the respiration intensity of the green peppers in the GHY-4 group was significantly reduced (p < 0.05), indicating that the treatment with Lactobacillus casei GHY-4 can delay the ripening and senescence of green peppers.

[0077] 6. Effects on soluble solids and titratable acid Soluble solids refer to all compounds dissolved in water in liquid or fluid foods, including sugars, acids, vitamins, minerals, etc. The content of soluble solids determines the taste of the fruit. Titratable acid content (TA) is an important factor affecting the flavor quality of green peppers and is also one of the important components of green pepper quality.

[0078] Take samples from the experimental group and the control group at 4 sampling time points (10 samples from each group at each time point). Take the fruit, freeze it in liquid nitrogen and then crush it. Weigh 5g of the frozen sample, put it in a mortar and grind it thoroughly, transfer all the fruit homogenate to a 100mL volumetric flask, and dilute it to the scale with distilled water, shake it well, let it stand for 30 minutes, then filter and collect the filtrate. Take the filtrate and use a PAL-1 digital saccharimeter to measure the titratable acid content conversion coefficient in terms of malic acid (%), and the soluble solid content conversion coefficient in terms of soluble sugar (%).

[0079] Results Figure 8 and Fig. 9 Compared with the green peppers in the CK group, the soluble solids content of the green peppers in the GHY-4 group was significantly increased, that is, the treatment with Lactobacillus casei GHY-4 can maintain a high soluble solids content in the green peppers. Compared with the green peppers in the CK group, the titratable acid content of the green peppers in the GHY-4 group was significantly increased.

[0080] 7. Effects on ascorbic acid content and chlorophyll content Ascorbic acid (VC) content is one of the important factors to measure the nutritional value of green pepper. Chlorophyll content directly affects the appearance quality of green pepper fruit. Samples of the experimental group and the control group were taken at 4 sampling time points (10 samples were taken from each group at each time point).

[0081] (1) Detection of ascorbic acid content (ammonium molybdate determination method) ①Solution preparation: Oxalic acid-EDTA solution: Take 6.3g oxalic acid and 0.75g disodium ethylenediaminetetraacetate and make up to 1000ml with distilled water.

[0082] 5% ammonium molybdate solution: Take 5g of ammonium molybdate and dilute to 100ml with distilled water.

[0083] 5% sulfuric acid solution: Add 1 part by volume of 98% sulfuric acid to 19 parts by volume of distilled water.

[0084] 20% glacial acetic acid solution: add 1 part glacial acetic acid to 5 parts distilled water.

[0085] Metaphosphoric acid-acetic acid solution: Take 15g metaphosphoric acid and 40ml 20% glacial acetic acid solution, add 250ml distilled water, dissolve and then make up to 500ml with distilled water.

[0086] ②Preparation of sample extract: Weigh 2 g of fresh sample, add 4 ml of oxalic acid-EDTA solution, grind into a homogenate, then rinse with 25 ml of distilled water and collect the liquid, then ultrasonically extract at 40°C for 15 min, then add distilled water to make the volume 50 ml, shake well and mix, filter, and collect the filtrate, which is the sample extract.

[0087] ③Determination: Take a 10ml test tube, add 5mL sample extract, 2mL oxalic acid-EDTA solution, 0.5mL metaphosphoric acid-acetic acid solution, 1mL 5% sulfuric acid solution and 2mL 5% ammonium molybdate solution, mix well and place in a 35℃ water bath for 30min, then measure the absorbance at 700nm with a spectrophotometer, and calculate the vitamin C content in the sample extract using the standard curve equation.

[0088] Standard curve equation: ; y is the absorbance, and x is the vitamin content in the test solution (g).

[0089] Calculate the vitamin C content (Vc) of the sampled samples.

[0090] ; C: Vitamin C content in sample extract; V t : Total volume of sample extract (50ml); W: fresh weight of sample (2 g); V m : Volume of sample extract added during measurement (5 ml).

[0091] (2) Detection of chlorophyll content (avoiding light throughout the process) Take 0.5g of fresh weight sample, add 4℃ precooled acetone-ethanol (mix 1 volume part of acetone with 1 volume part of ethanol), homogenize, then filter with filter paper, collect the filtrate in a 50mL brown volumetric flask, leave until the filtrate turns white, then dilute to 50mL mark with sterile water, which is the sample extract. Measure the absorbance of the sample extract at 663nm and 645nm. Calculate the chlorophyll a concentration (ρ a ), chlorophyll b concentration (ρ b ) and chlorophyll concentration (ρ t). Calculate the chlorophyll content of the sample in mg / g.

[0092] .

[0093] Results Fig.10 and Fig.11 During storage, the VC content of green pepper fruit showed an overall downward trend. Lactobacillus casei GHY-4 treatment slowed down the decline of VC in green pepper fruit, keeping its content at a higher level, which was significantly different from the CK group (p < 0.05). As the storage time increased, the chlorophyll content in green peppers showed a downward trend, and the chlorophyll content of green peppers in the GHY-4 group was significantly higher than that in the CK group (p < 0.05).

[0094] The results of this example show that Lactobacillus casei GHY-4 has the effect of delaying ripening and inhibiting rot in the early stage of storage of green peppers.

[0095] The present invention has been described in detail above. It will be apparent to those skilled in the art that the present invention may be implemented in a wide range under equivalent parameters, concentrations and conditions without departing from the spirit and scope of the present invention and without the need for unnecessary experimentation. Although the present invention provides specific embodiments, it should be understood that further improvements may be made to the present invention. In short, according to the principles of the present invention, this application intends to include any changes, uses or improvements to the present invention, including changes made by conventional techniques known in the art that depart from the scope disclosed in this application. Applications of some of the basic features may be made within the scope of the following appended claims.

Claims

1. Lactobacillus casei ( lactobacillus casei ) GHY-4, whose deposit registration number is CGMCC No.31925.

2. the bacterial agent of Lactobacillus casei described in claim 1.

3. Application of Lactobacillus casei described in claim 1 or bacterial agent described in claim 2 in inhibiting Alternaria alternata.

4. Use of the Lactobacillus casei described in claim 1 or the bacterial agent described in claim 2 in the preparation of an Alternaria inhibitor.

5. Application of the Lactobacillus casei described in claim 1 or the bacterial agent described in claim 2 in green pepper preservation.

6. Use of the Lactobacillus casei described in claim 1 or the bacterial agent described in claim 2 in the preparation of a green pepper preservative.

7. The use of the Lactobacillus casei according to claim 1 or the bacterial agent according to claim 2, which is any one of the following (a) to (i): (a) Inhibit the rot of green pepper fruit; (b) delaying the ripening process of green pepper fruits after they are picked; (c) delaying the loss of firmness of green pepper fruits after picking; (d) inhibiting the increase in cell membrane permeability after picking of green pepper fruits; (e) Reduce the respiration rate of green pepper fruits; (f) increasing the soluble solids content of green pepper fruit; (g) inhibiting the degradation of titratable acid in green pepper fruit; (h) increasing the ascorbic acid content of green pepper fruit; (i) Increase the chlorophyll content of green pepper fruits.

8. Use of the Lactobacillus casei according to claim 1 or the bacterial agent according to claim 2 in preparing a product; The use of the product is any of the following (a) to (i): (a) Inhibit the rot of green pepper fruit; (b) delaying the ripening process of green pepper fruits after they are picked; (c) delaying the loss of firmness of green pepper fruits after picking; (d) inhibiting the increase in cell membrane permeability after picking of green pepper fruits; (e) Reduce the respiration rate of green pepper fruits; (f) increasing the soluble solids content of green pepper fruit; (g) inhibiting the degradation of titratable acid in green pepper fruit; (h) increasing the ascorbic acid content of green pepper fruit; (i) Increase the chlorophyll content of green pepper fruits.

9. A product comprising the Lactobacillus casei according to claim 1 or the bacterial agent according to claim 2.

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