Method for shortening growth period of tobacco

Abstract

The invention provides a method for shortening the growth period of tobacco. The invention finds the specific new application of the bacillus altitudinis NM17 (collection number is CGMCC NO.31273): (1) the harvesting period of tobacco is shortened, and the tobacco is harvested in advance; (2) tobacco leaf maturity and uniformity are improved, and tobacco leaf layering yellowing is promoted; (3) the decomposition of starch granules is promoted, and the quality of tobacco leaves is improved. The method has a great application prospect in improving the maturity of the tobacco leaves and promoting the early harvesting of the tobacco leaves.

Description

Technical Field

[0001] The present invention relates to the technical field of microbiology, and particularly relates to a method for shortening the growth period of tobacco. Background Art

[0002] Tobacco is an important cash crop in China, and the yield and quality of tobacco leaves are the key to the development of the tobacco industry. However, with the frequent occurrence of extreme weather events caused by global climate change, combined with the unreasonable rotation mode and lack of scientific fertilization management, the tobacco leaf production faces severe challenges such as difficult late yellowing, insufficient maturity, and quality decline, which have a significant impact on the sustainable development of the tobacco leaf industry. Therefore, in response to the key problems in the maturity period of tobacco leaves, it is urgent to take effective countermeasures to accelerate the accumulation and transformation of dry matter in tobacco plants, improve the maturity of tobacco leaves, and promote early harvesting. This is not only the core strategy for realizing high-quality flue-cured tobacco production, but also the key path for promoting the high-quality development of the tobacco industry.

[0003] At present, the technical means for promoting the maturity and yellowing of tobacco leaves and shortening the growth period mainly include chemical regulation, agronomic measures, and biological technology applications. Among them, chemical regulation mainly uses plant growth regulators such as ethephon and abscisic acid, and exogenous spraying is used to promote the maturity and yellowing of tobacco leaves. However, chemical regulation has a residue risk, which affects the quality and safety of tobacco leaves and has a greater negative impact on the environment. Agronomic measures mainly include reasonable close planting, optimized fertilization (such as controlling nitrogen and increasing potassium), water management, and topping and suckering removal, etc., but the effects are unstable and are greatly restricted by climate and soil conditions. The application of biological technology is a hot topic in recent years, but the research mainly focuses on rhizosphere microorganisms with growth-promoting functions, which promote the accumulation and transformation of dry matter by regulating the physiological metabolism of tobacco plants, and then accelerate the maturity of tobacco leaves. There is a lack of special microbial agents specifically for the maturity of late-stage tobacco leaves.

[0004] Although the existing technologies can promote the maturity of tobacco leaves to a certain extent, there are still problems such as unstable effects and high environmental risks. Therefore, it is necessary to develop a method for shortening the growth period of tobacco. Summary of the Invention

[0005] The object of the present invention is to provide a method for shortening the growth period of tobacco. The present invention discovers that Priestia megaterium NM17 can shorten the growth period of tobacco, effectively regulate the maturity process of tobacco leaves, promote early harvesting, and improve the uniformity of tobacco leaf harvesting, and has important production application value.

[0006] To achieve the above object, the present invention adopts the following technical scheme:

[0007] In the first aspect of the present invention, there is provided a method for shortening the growth period of tobacco, the method comprising:

[0008] The bacterial solution of *Priestia megaterium* NM17 is diluted and then sprayed on the leaf surface. The preservation number of *Priestia megaterium* NM17 is CGMCC NO. 31273.

[0009] Furthermore, the method for preparing the bacterial solution of *Priestia megaterium* NM17 includes: inoculating the *Priestia megaterium* NM17 into a liquid medium for fermentation culture to obtain the NM17 fermentation broth. The conditions for the fermentation culture include: the temperature is 26-30 °C, and the pH is 5-9.

[0010] Furthermore, the spraying method specifically includes:

[0011] The NM17 fermentation broth (OD600 = 0.3, 3×10 8 cfu / ml) is diluted 100-300 times to obtain a dilution, and then the dilution is sprayed. 30 L of the dilution is sprayed per mu. The density of *Priestia megaterium* NM17 in the NM17 fermentation broth: OD600 is 0.2-0.4, 1×10 8 -3×10 9 cfu / ml. Preferably, OD600 = 0.3, 3×10 8 cfu / ml.

[0012] Furthermore, the number of times of the leaf surface spraying is ≥2 times, and the spraying interval is 7-10 days.

[0013] Furthermore, the time for the leaf surface spraying includes: 7-10 days after topping or 20 days before harvesting.

[0014] In the second aspect of the present invention, there is provided the application of *Priestia megaterium* NM17 in shortening the growth period of tobacco. The preservation number of *Priestia megaterium* NM17 is CGMCC NO. 31273.

[0015] In the third aspect of the present invention, there is provided a composition for shortening the growth period of tobacco. The composition includes:

[0016] *Priestia megaterium* NM17 (preservation number: CGMCC NO. 31273) 0.5-2 wt%;

[0017] Alginate oligosaccharide 1-3 wt%;

[0018] Carrier 95-98 wt%.

[0019] Furthermore, the molecular weight of the alginate oligosaccharide is 80-300 Da.

[0020] Furthermore, the carrier is selected from one of chitosan oligosaccharide, amino acid, and glucose.

[0021] In the fourth aspect of the present invention, there is provided the use of the composition in shortening the growth period of tobacco.

[0022] One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:

[0023] A method for shortening the growth period of tobacco provided by the present invention is to dilute the bacterial liquid of Priestia megaterium NM17 and then spray it on the leaf surface. The present invention discovers that the NM17 strain can accelerate the senescence process of tobacco leaves, promote the degradation of chlorophyll, improve the maturity of tobacco leaves, and the maturity period is 5 - 10 days earlier than that of the control group, which is beneficial to early harvesting. It can also improve the uniformity of yellowing in the tobacco field and the consistency of tobacco leaf maturity, reduce the coefficient of variation in the field, and create favorable conditions for mechanized harvesting. The results show that the application of the NM17 strain can effectively regulate the maturity process of tobacco leaves, enable early harvesting, and improve the uniformity of tobacco leaf harvesting, having important production application value.

[0024] The preservation date of Priestia megaterium NM17 of the present invention is July 11, 2024, and the preservation number is CGMCC NO. 31273. Its taxonomic name is Priestia megaterium, and the preservation unit is the China Center for Type Culture Collection, with the address being Institute of Microbiology, Chinese Academy of Sciences, No. 3, Beichen West Road, Chaoyang District, Beijing 100101. Priestia megaterium NM17 was screened by the inventors of the present application in the early stage, and the patent number is CN119040221B. Description of the Drawings

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0026] Figure 1 Comparison of the field growth after spraying NM17 twice in a conventional tobacco field;

[0027] Figure 2 Comparison of the field growth after spraying NM17 twice in a tobacco field with late - maturing and over - lush growth;

[0028] Figure 3 Comparison of the field growth after spraying NM17 twice in a tobacco field with black - blast;

[0029] Figure 4 Comparison of the yellowing situation of tobacco leaves after spraying NM17 twice;

[0030] Figure 5Observation on the ultrastructure of tobacco leaves after spraying NM17 bacterial solution; among them, A - B are electron micrographs of the ultrastructure of tobacco leaves in the control group, and the arrow indicates the chloroplast; C - D are electron micrographs of the ultrastructure of tobacco leaves treated with alginate oligosaccharides by spraying. Detailed implementation manners

[0031] The following will specifically elaborate on the present invention in combination with the detailed implementation manners and examples, and the advantages and various effects of the present invention will be presented more clearly therefrom. Those skilled in the art should understand that these detailed implementation manners and examples are used to illustrate the present invention, rather than limiting the present invention.

[0032] Throughout the specification, unless otherwise specifically stated, the terms used herein should be understood as having the meanings commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as the general understanding of those skilled in the art to which the present invention pertains. In case of conflict, this specification shall prevail.

[0033] Unless otherwise specifically stated, various raw materials, reagents, instruments, and equipment used in the present invention can be obtained through market purchase or by existing methods.

[0034] The following will specifically describe a method for shortening the growth period of tobacco in the present application in combination with examples and experimental data. Example 1: Preparation of the bacterial solution of Priestia megaterium NM17

[0035] The preserved Priestia megaterium NM17 was activated and then inoculated into NA liquid medium for fermentation culture to obtain the NM17 fermentation broth. The conditions for the fermentation culture include: the temperature is 26 - 30 °C, and the pH is 5 - 9, to obtain the fermentation broth;

[0036] The NM17 fermentation broth (OD600 = 0.3, 3×10 8 cfu / ml) was diluted 100 - 300 times for absorption to obtain a dilution for subsequent spraying.

[0037] Example 2: Field experiment

[0038] 1. Experimental design

[0039] Representative tobacco fields were selected in the Shandong tobacco-growing area for foliar spraying treatment. The experimental design and plot selection are shown in Table 1.

[0040] Table 1 Experimental design and plot selection

[0041]

[0042] The so-called conventional treatment refers to the practice in accordance with local production experience or local tobacco production management technical standards, and mainly includes the following methods: 1. Foliar spraying of potassium dihydrogen phosphate; 2. Circumcision at the base of the stem in the tobacco fields with vigorous growth; 3. Ripening products (such as Dahong Potassium, maleic hydrazide, etc.) on the agricultural materials market; 4. No treatment and natural yellowing. The conventional treatment for normal tobacco fields in this study is no treatment and natural yellowing; the conventional treatment for late-maturing and overgrown tobacco fields is spraying potassium dihydrogen phosphate (150 g / mu); the conventional treatment for tobacco fields with vigorous growth is spraying potassium dihydrogen phosphate (150 g / mu) + circumcision.

[0043] 2. Index determination

[0044] 2.1 Harvest period record

[0045] According to the maturity of tobacco leaves in the field, record the harvest time of tobacco leaves under different treatments.

[0046] 2.2 Photographing of the growth in the field

[0047] After spraying twice, use a drone to take pictures of the growth in the field under different treatments and compare the changes in leaf color.

[0048] 2.3 Observation of the ultrastructure of leaves

[0049] Cut several small pieces of about 2 mm × 2 mm at the lower right side of the midrib of fresh tobacco leaves, put them into 2.5% glutaraldehyde phosphate buffer solution (pH 7.2), and evacuate until the materials sink at room temperature, then place them in a refrigerator at 4°C for fixation for more than 72 h. Clean, dehydrate, dry, mount the samples and observe and photograph them under a Hitachi S-3000 scanning electron microscope.

[0050] Test results

[0051] 3.1 Comparison of harvest periods under different treatments

[0052] Table 2 Record of the harvest time of tobacco fields under different treatments

[0053]

[0054] It can be seen from the table that the tobacco fields treated with the NM17 strain can promote the ripening of tobacco leaves and advance the harvest. For normal tobacco fields, the third harvest is advanced by 2 days and the final harvest is advanced by 5 days. For late-maturing and overgrown tobacco fields, the second harvest is advanced by 3 days, the third harvest is advanced by 5 days, and the final harvest is advanced by 7 days. For tobacco fields with vigorous growth, the second harvest is advanced by 4 days, the third harvest is advanced by 6 days, and the final harvest is advanced by 10 days. As the difficulty of tobacco leaf harvesting and baking increases, the number of days advanced in the harvest period is more when using foliar spraying of the NM17 strain.

[0055] 3.2 Comparison of the yellowing situation of tobacco leaves in the field under different treatments

[0056] The comparison results of the growth of tobacco fields under conventional treatment and after spraying NM17 twice are as follows Figure 1 shown;

[0057] The comparison of the growth of over - green and late - maturing tobacco fields under conventional treatment and after spraying NM17 twice is as Figure 2 shown;

[0058] The comparison of the growth of black - explosive tobacco fields under conventional treatment and after spraying NM17 twice is as Figure 3 shown;

[0059] The comparison of the yellowing situation of tobacco leaves after spraying NM17 twice is as Figure 4 shown;

[0060] By observing and comparing the growth of different tobacco fields, the treatment group sprayed with NM17 strain twice showed significant physiological effects. Specifically, (1) the senescence process of tobacco leaves was significantly accelerated, the chlorophyll degradation rate increased, and the tobacco leaves matured earlier; (2) the uniformity of yellowing was significantly improved, the field coefficient of variation decreased, and the maturity was consistent.

[0061] 3.3 Observation and analysis of leaf ultrastructure

[0062] Through the observation of the ultrastructure of tobacco leaves (as Figure 5 shown), it was found that the cell membrane and cell wall structures of the control group leaves were complete and clear. Each organelle was squeezed to the cell edge by the vacuole and arranged orderly. Among them, the thylakoid structure of chloroplasts was clearly visible, and there were a small number of starch grains. It could be judged that the synthesis of starch and others in the control group leaves was vigorous, and the leaves were still in the development stage. However, the electron microscope results of the NM17 strain treatment group showed that organelles such as chloroplasts were gradually decomposed, the plastid membrane was ruptured, and a large amount of starch grains accumulated and began to degrade. It could be judged that the leaves of the treatment group had reached the mature stage.

[0063] 4. Experimental conclusions

[0064] Through the above - mentioned data analysis of different tobacco fields and the comparison results of growth, the treatment group sprayed with NM17 strain twice showed significant physiological effects. The NM17 strain can accelerate the senescence process of tobacco leaves, promote the degradation of chlorophyll, improve the maturity of tobacco leaves. The maturity period is 5 - 10 days earlier than that of the control group, which is beneficial to early harvesting. It can also improve the uniformity of yellowing in the tobacco field and the consistency of tobacco leaf maturity, reduce the field coefficient of variation, and create favorable conditions for mechanical harvesting. The results show that the application of the NM17 strain can effectively regulate the maturity process of tobacco leaves, advance the harvest, improve the uniformity of tobacco leaf harvest, and has important production application value.

[0065] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent substitution methods and are all included in the protection scope of the present invention.

[0066] Finally, it should also be noted that the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device.

[0067] Although embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications once they learn the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the embodiments and all changes and modifications falling within the scope of the present invention.

[0068] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

1. A method for shortening the growth period of tobacco, characterized in that, The method includes: Using the diluted bacterial solution of Priestia megaterium NM17 for foliar spraying, and the preservation number of Priestia megaterium NM17 is CGMCC NO. 31273.

2. The method for shortening the growth period of tobacco according to claim 1, characterized in that The preparation method of the bacterial solution of Priestia megaterium NM17 includes: inoculating the Priestia megaterium NM17 into a liquid medium for fermentation culture to obtain the NM17 fermentation broth, and the conditions for the fermentation culture include: the temperature is 26-30 °C, and the pH is 5-9.

3. The method for shortening the growth period of tobacco according to claim 2, characterized in that, The specific spraying method includes: Diluting the NM17 fermentation broth 100-300 times to obtain a dilution solution and then spraying it, and spraying 30 L of the dilution solution per mu.

4. A method for shortening the growth period of tobacco according to claim 3, characterized in that, The number of times of foliar spraying is ≥2 times, and the spraying interval is 7-10 days.

5. A method for shortening the growth period of tobacco according to claim 1, characterized in that, The time of foliar spraying includes: 7-10 days after topping or 20 days before harvesting.

6. Application of Megasphaera elsdenii NM17 in shortening the growth period of tobacco, characterized in that, The preservation number of Priestia megaterium NM17 is CGMCC NO. 31273.

7. A composition for shortening the growth period of tobacco, characterized in that, The composition contains 0.5-2 wt% of Priestia megaterium NM17 (preservation number: CGMCC NO. 31273).

8. Application of the composition according to claim 7 in shortening the growth period of tobacco.

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