JPH0377803A - Method for preventing soil disease injury - Google Patents

Abstract

PURPOSE:To effectively prevent soil disease injury such as soil infectious disease by culturing a microorganism capable of producing an antibiotic substance, accumulating a polyhydroxybutyrate in microbial cells thereof, converting the microorganism into a starved state, mixing the resultant microorganism with a carrier, improving adsorptivity and then applying the obtained mixture to soil. CONSTITUTION:A microorganism which is a microorganism of the genus Pseudomonas or Bacillus capable of producing an antibiotic substance is cultured to accumulate a polyhydroxybutyrate (hereinafter abbreviated to PHB) in microbial cells thereof. The resultant microorganism is then mixed with a nonnutritious substance such as water so as to provide about 10<8> to 10<14> microbial cells/g microbial cell concentration and converted into a formed starved state. The obtained microorganism is subsequently mixed with a carrier such as rice straw and then directly applied to soil or allowed to stand at ordinary temperature for 1-7 days and sudsequently applied to the soil. A well-known method is adopted as a culturing method for accumulating the aforementioned PHB in the microbial cells and the microorganism is cultured in a culture medium containing a small amount of an N source such as meat extract culture medium or potato dextrose culture medium and then cultured in a culture medium containing only a C source to more effectively accumulate the PHB therein.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for preventing soil diseases, and more particularly, to a method for preventing soil diseases using antibiotic-producing bacteria for the purpose of controlling soil-borne diseases.

[Problems to be solved by conventional techniques and inventions] Currently,
Chemical drugs such as methyl bromide and chloropicrin are used to prevent the growth of two-ring pathogens caused by year-round or continuous cultivation of agricultural crops.

As a result, beneficial microorganisms in the soil die, the soil loses its vitality, and productivity is decreasing. Furthermore, the unripe organic fertilizers applied to regenerate the soil have caused pests such as nematodes and mites to increase more than ever before, which in turn leads to the use of even more pesticides, and the vicious cycle is repeated.

In recent years, as an alternative to these chemical pesticides, methods have been used to prevent soil diseases by utilizing the antagonistic effects of microorganisms, and these methods are now commercially available as soil conditioners and antagonistic microbial materials. However, these have the problem that they lack stability during distribution and storage, and cannot exhibit sufficient effects when applied to soil due to a decrease in the number of bacteria and weakening of the bacteria. Furthermore, even if soil is treated with a sufficient amount of useful bacteria, there is a problem in that it does not show any effective effects due to poor colonization.

[Failure to solve the problem]

As a result of intensive research in order to solve the above problems, the present inventors have found that by starving antibiotic-producing bacteria that have accumulated polyhydroxybutyrate (hereinafter abbreviated as PHB) in their bodies, they can The present invention was completed based on the discovery that adsorption with the carrier mixed at the time of application is improved and soil diseases can be effectively prevented.

That is, the present invention provides a method for preventing soil diseases, which is characterized by culturing antibiotic-producing bacteria to accumulate PH8 in their cells, then starving them, and then applying the mixture to soil after mixing with a carrier. be.

The antibiotic-producing bacteria used in the present invention include Pseudomonas (Pseudo++onas) genus or Bacillus (Bacillus).
Examples include bacteria of the genus ac i 11 us). Pseu
The genus domonas includes Pseudoa+onas
(hereinafter abbreviated as P) cepacia.

P, gladioli, P, mallei,, P, p
seudomallei SP, pi-ckettiSP
, eolanacearut, P, voransSP
, 5teroni.

P. delafieldii, P. facilis S.
P, 5accharophila.

P, flava, P, pseudoflava
, P. palleronii, P.

caryophylli, P. diminuta,
Examples include P, vesicularis, etc., preferably P, cepacia, P, gla-dioli. Also, in the genus Bacillus, Bacillus
(hereinafter abbreviated as B) cereusSB, anthrac
is, B, azo-tofora+ansSB, my
coidess B, thuringiensis, etc., and preferably B, cereus, B, myc.
It is oides.

The starvation state in the present invention is formed by mixing bacterial cells with a non-nutritive substance such that the bacterial cell concentration is approximately 10 m-14 cells/g. Examples of non-nutritive substances include water or aqueous solutions that do not contain carbon or nitrogen sources, lightweight porous inorganic carriers, zeolite, diatomaceous earth, perlite,
Examples include bentonite, Oya stone, anthrite, limestone, vermiculite, etc. singly or in combination, but the materials are not limited to the above as long as they do not contain a nutrient source.

However, particularly preferred among these is water.

Examples of carriers used in the present invention include rice straw, rice husk, vermiculite, fossilized shells, peat moss, dried livestock dung, rice bran, gypsum, bone meal, plant ash, and inorganic carriers, among which rice straw and rice husk are more preferred. .

A known method is employed as a culture method for accumulating PUB within the bacterial cells. That is, it is cultured in a medium with a low nitrogen source, such as meat extract medium or potato dextrose medium. After this culture, PUB is accumulated even more effectively when the cells are further cultured in a medium containing only a carbon source. After the bacterial cells cultured as described above are mixed with the non-nutritive substances mentioned above, they are left at room temperature for several hours to several months, preferably for about 1 day to 7 days. After that, dilute with water so that the bacterial cell concentration is about 10" cells/g.
The weight ratio of it and the carrier is 1:0.1 to 1:20,
It is preferably mixed with the above carrier in a ratio of about 1:1 to 1:5.

Thereafter, it is applied to the soil immediately or after being left at room temperature for about 1 to 7 days, more preferably about 1 to 2 days.

〔Example〕

The present invention will be explained more specifically by the following examples.
The present invention is not limited to these examples.

Table 1 shows typical microorganisms used in the examples.
These are all known strains that produce antibiotics.

Table 1 Examples 1 to 5 and Comparative Examples 1 to 5 After shaking or statically culturing the various bacterial bodies shown in Table 1 in a meat extract-peptone liquid medium (manufactured by Difco) at 30°C for 16 to 48 hours, After collecting bacteria by centrifugation and washing 5 times with pure water, the final concentration of bacteria was 10 cells/g.
Pure water was added and mixed to a certain level, and the mixture was left at room temperature for 5 days to create a starvation state (Examples 1 to 5).

Moreover, instead of the starvation state described above, a meat extract-peptone solution was used as a nutrient source instead of pure water to create a nutrient-rich state (Comparative Example 1=5).

Then, after diluting 1000-fold using pure water for the starved bacterial cells and the same liquid medium for the nutrient-rich bacterial cells, pre-sterilized rice straw was added at a weight ratio of 1:1.
1 and stored at 20° C. on a shear, the number of viable cells was measured over time, and the survival rate of the cells was determined.

The number of viable bacteria was determined by diluting the sample at a certain ratio and inoculating it on an ordinary agar medium (manufactured by Hinaga Pharmaceutical Co., Ltd.), and calculating the number of colonies after 48 hours.

The results are shown in Table 2.

Example 6 and Comparative Examples 6 to 7 Using Pseudomonas cepacla, an image was prepared by the method shown in Example 1 and Comparative Example 1, and then similarly adsorbed onto unsterilized rice straw, and after 5 days, the soil weight was A 1% amount was applied to the soil, and the incidence of various soil diseases was determined using the following formula (Example 6 and Comparative Example 6).

In addition, the incidence of various soil diseases was determined in the same manner for soil to which no bacterial cells were applied (Comparative Example 7).

The results are shown in Table 3.

Table 3

Claims (1)

[Scope of Claims] 1. Soil disease prevention characterized by culturing antibiotic-producing bacteria and accumulating polyhydroxybutyrate within the bacterial cells, starving the bacteria, mixing with a carrier, and applying to soil. Law. 2. The antibiotic-producing bacterium is Pseudomonas (Pseu-d
2. The method for preventing soil diseases according to claim 1, wherein the bacterium belongs to the genus Bacillus or the genus Bacillus.