CN-121991868-A - Construction method of aeromonas veronii over-expression micC attenuated strain, strain and application thereof

Abstract

The application relates to an attenuated aeromonas veronii which is preserved in the microorganism strain preservation center of Guangdong province at the 12 th month of 2025 and the preservation number is GDMCC NO.67551. The toxicity of the mutant strain of the aeromonas veronii is greatly reduced, a good attenuation effect is achieved, and the possibility is provided for preparing attenuated live vaccines of the aeromonas veronii.

Inventors

• MA XIANG
• Guo Lanjuan
• XIONG YUESHENG
• GAO SHIJIE

Assignees

• 海南大学

Dates

Publication Date

20260508

Application Date

20251231

Claims (10)

1. 1. An attenuated Aeromonas verrucosa was deposited at the microorganism strain collection of Guangdong province at 2025, 12 months and 26 days under the deposit number GDMCC NO. 67551.
2. 2. A construction method of an attenuated strain of aeromonas veronii comprises the steps of treating aeromonas veronii by a genetic engineering technology means to enable micC genes in the aeromonas veronii to be over-expressed.
3. 3. The construction method according to claim 2, wherein the nucleotide sequence of micC gene is shown as SEQ ID NO. 1.
4. 4. The construction method according to claim 2, wherein the Aeromonas verrucosa belongs to the genus Aeromonas.
5. 5. The construction method according to claim 2, wherein the genetic engineering technique is a homologous recombination technique.
6. 6. An attenuated aeromonas veronii constructed by the construction method of any of claims 2-5.
7. 7. Use of attenuated aeromonas veronii or a secretion thereof according to claim 1 or 6 for the preparation of an attenuated aeromonas veronii vaccine.
8. 8. The use according to claim 7, wherein the vaccine is for the prevention of infection by aeromonas veronii by organisms, preferably fish, livestock, poultry, pets.
9. 9. Use of attenuated aeromonas veronii or its secretions according to claim 1 or 6 for enhancing the immune response of an organism.
10. 10. A fish feed additive comprising the attenuated aeromonas veronii or its secretion according to claim 1 or 6.

Description

Construction method of aeromonas veronii over-expression micC attenuated strain, strain and application thereof Technical Field The invention relates to the field of genetic engineering, in particular to a construction method of a aeromonas veronii over-expression micC attenuated strain, the strain and application thereof. Background Aquaculture occupies almost half of the global fish production and is also an important economic source in coastal areas of countries. Aeromonas veronii (Aeromonas veronii C4 or A. Veronii C4) has become a serious human-animal-fish co-pathogen in aquaculture as a gram-negative bacteria that is widely present in aquatic environments. The aeromonas veronii has wide host range and can infect various freshwater or marine economic animals. The research shows that the strain can cause the surface ulcer of the largemouth black bass, the hyperemia and hemorrhage of gill wires, and the swelling of livers, spleens and kidneys, and the histopathological observation shows that obvious denaturation, necrosis and inflammatory cell infiltration of the tissues occur. In Lateolabrax japonicus, infection with Aeromonas verrucosa causes acute death with pathological changes such as abdominal bleeding, anal redness, bleeding and congestion of kidneys and livers, and swelling of spleen. In addition, the infection capability of the strain on the macrobrachium rosenbergii is very remarkable, and the strain of aeromonas veronii WSQ-1 isolated from the diseased macrobrachium rosenbergii has stronger pathogenicity on the prawn body, and the half-lethal concentration of the strain reaches 2.51 multiplied by 10 6 CFU/mL in 72 hours. In the cultivation of Chinese soft-shelled turtles, aeromonas veronii is identified as one of the main pathogenic bacteria. Aeromonas veronii is one of the important fish pathogens, and has been a constant threat to aquaculture and public health. On the one hand, abuse of antibiotics has led to an increasing problem of resistance. The study shows that Aeromonas veronii isolated from different aquatic animals presents different degrees of drug resistance to commonly used fishery drugs. For example, the largemouth black bass source strain is resistant to doxycycline, tetracycline and amoxicillin, while the macrobrachium rosenbergii source strain is resistant to 10 drugs such as clarithromycin and the like, and only shows moderate sensitivity to kanamycin. The nile tilapia source aeromonas veronii even has complete drug resistance to ampicillin, tigecycline and the like, and presents a multi-drug resistant phenotype. On the other hand, the conventional prevention and control method has limitations. The problems of residue and environmental pollution caused by chemical medicine use, limited immune protection rate of inactivated vaccines and other factors, have prompted researchers to seek safer and more effective alternatives. The research and development of the live vaccine are taken as an effective strategy for preventing and controlling the bacterial infection, and the live vaccine has urgent production needs and wide application prospect. Disclosure of Invention Aiming at the technical problems in the prior art, the invention provides an attenuated aeromonas veronii which is preserved in the Guangdong province microorganism strain preservation center at the 12 th month of 2025 and the 26 th day, wherein the preservation number is GDMCC NO. 67551, and the Latin name is Aeromonas veronii. A construction method of an attenuated strain of aeromonas veronii comprises the steps of treating aeromonas veronii by a genetic engineering technology means to enable micC genes in the aeromonas veronii to be over-expressed. The construction method is as described above, wherein the nucleotide sequence of micC gene is shown as SEQ ID NO. 1. The construction method is as described above, wherein the Aeromonas veronii belongs to the Aeromonas veronii species of the genus Aeromonas. The construction method is characterized in that the genetic engineering technical means is a homologous recombination technology. An attenuated aeromonas veronii constructed by the construction method of any of claims 2-5. The use of attenuated aeromonas veronii or a secretion thereof as described above for the preparation of an attenuated aeromonas veronii vaccine. For use as described above, the vaccine is for use in the prevention of infection by aeromonas veronii by organisms, preferably fish, livestock, poultry, pets. Use of an attenuated aeromonas veronii or a secretion thereof as described above for increasing an immune response in an organism. A fish feed additive comprising attenuated aeromonas veronii or a secretion thereof as described above. The toxicity of the mutant strain of the aeromonas veronii is greatly reduced, a good attenuation effect is achieved, and the possibility is provided for preparing attenuated live vaccines of the aeromonas veronii. Drawings Preferred embodiments of the present invent