JP3231744B2 - Violet purple wilt fungus isolate V-70 having low pathogenicity and purple wilt disease controlling agent containing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a purple wilt disease fungus with reduced pathogenicity and a purple wilt control agent containing the fungus.

[0002]

2. Description of the Related Art Purple scab is a soil-borne plant disease that affects more than 120 plants of 50 families, such as apple, sweet potato, asparagus, alfalfa, and mulberry. The pathogen is Helicobasidium monpa belonging to Basidiomycetes (Helic
obasidium mompa). This fungus forms a purple-brown mycelium and a sclerotium on the surface of the diseased root in soil, and a deep purple-brown to red-brown felt-like fruit body at the ground and aerial parts. Spores survive for a long time and are a major source of infection. The disease occurs in undeveloped soils that have not yet been cleared and are low in volcanic ash, soft and well-permeable, rich in undegraded organic matter, high in C / N ratio and low in pH.

Helicobasidium monpa mainly affects the underground roots of plants. For this reason, the affected area cannot be easily observed, and the discovery of the disease is delayed. When symptoms appear on the ground and the disease is noticed, it is generally impossible to treat the disease. It is a difficult disease.

Conventionally, the method of controlling purple scab is carried out by irrigation with a chemical pesticide or the like. However, this method has a problem of environmental pollution, and a new control method without fear of causing environmental pollution is desired. In recent years, biological pesticides have attracted attention as alternatives to chemical pesticides. Biological pesticides use insects and microorganisms that infect and parasitize pests such as pests, weeds, and disease germs, and are expected to be safe pesticides that have less impact on the human body and surrounding environment than chemical pesticides. I have. And to date, Agrobacterium radiobacto
Bacillus subtilis, an agent for controlling rose root carcinoma using r
Dozens of biological pesticides have been developed, such as tomato and eggplant gray fungus control agents, which use phenol. However, there is no known biological pesticide for controlling purple wilt fungus.

[0005]

An object of the present invention is to provide a purple vine disease isolate V-70 having reduced pathogenicity, and a purple wilt control agent containing the same.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, the purple pathogen having low pathogenicity among the purple pathogens stored at the Fukushima Fruit Tree Experimental Station. The disease was successfully isolated, and the present invention was completed. That is, the present invention is a purple pathogen isolate V-70 having low pathogenicity. Furthermore, the present invention is a purple wilt disease controlling agent comprising the purple wilt disease isolate V-70 as an active ingredient. Hereinafter, the present invention will be described in detail.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The purple wilt fungus of the present invention is different from the normal pathogenic purple wilt fungus and has low pathogenicity to plants (hereinafter referred to as low pathogenic purple wilt fungus). It is. 1. Isolation of low-pathogenic purple wilt fungus Low-pathogenic purple wilt disease, pathogenicity test using carrot, pathogenic purple wilt disease (e.g., standard strain V-18) as a control, You can choose from culture stock. That is, for example, first, bacteria pre-cultured in a suitable medium (for example, potato decoction agar medium) capable of growing purple wilt fungi are inoculated on sterilized mulberry cuttings, and this is inoculated at 20 to 30 ° C. And culture for 10-100 days. The obtained culture is used as an inoculum. The obtained mulberry branch and carrot are connected using a toothpick. Next, the inoculated carrot is transplanted into a container containing an appropriate culture soil (for example, Kanuma soil, Kanuma soil: humus = 1: 1 or vermiculite: humus = 1: 1), and stored at 15 to 30 ° C. for 1 to 3 months. Cultivate.
FIG. 1 is a schematic diagram showing a state during cultivation. And
Pathogenicity is determined by visually observing the bacteria spread on the carrot roots. For example, pathogenicity can be rated on a scale of 0-5. That is, 0 when no hyphae is seen, 1 when a hyphae bundle is formed, 2 when a hyphae and infection locus are formed, 3 when the tissue is softly decomposed, and a hyphal membrane is formed. Is evaluated as 4 if the root is mummy, and 5 if the root is mummy. In this evaluation criterion, a case in which the evaluation is less than half of 4.75 of the standard strain can be evaluated as low pathogenicity.

[0008] The low-pathogenic purple wilt fungus obtained in the present invention is named isolate V-70, identification number NMV-70, accession number.
August 1999 as FERM P-17536 at the Institute of Biotechnology and Industrial Technology (I 1-3, Higashi 1-3-1, Tsukuba, Ibaraki Prefecture)
Deposited on 27th.

[0009] 2. Biological pesticide The low pathogenic purple stripe disease isolate V-70 of the present invention is infected with a dsRNA virus that reduces the pathogenicity of purple stripe disease. The dsRNA virus is a low-pathogenic purple stripe disease isolate V-7
From 0, it is transmitted to the pathogenic P. vulgaris causing a decrease in P. vulgaris virulence. Therefore, by adding the low-pathogenic purple wilt fungus of the present invention as a basidiomycete preparation to plants that may be affected by purple wilt and soil that becomes the source of infection, purple wilt is controlled. be able to.

Plants to be protected by basidiomycete preparations include apples, pears, loquats, grapes, citrus, peaches, apricots, plums, oysters, and figs. If so, you are not limited to these plants.

The basidiomycete preparation of the present invention can be prepared by culturing low pathogenic purple wilt disease on a potato decoction medium or the like, collecting the cells, and adsorbing the obtained cells appropriately. The obtained cells are mixed with a suitable adsorbent (e.g., zeolite or the like) or a suitable dispersion medium (e.g., those containing skimmirum, sodium glutamate, sorbitol, and the like as cell protection components), and then concentrated or dried. be able to.

A method for producing a basidiomycete preparation using an adsorbent is illustrated in FIG. First, the low pathogenic purple wilt fungus of the present invention,
After culturing in a medium such as a potato decoction medium using a jar fermenter (step a), the obtained cells are collected by centrifugation (step b). Next, the collected cells are suspended in water or a buffer (step c), an adsorbent is added to the obtained cell suspension, and the cells are adsorbed to the adsorbent by sufficiently stirring (step c). d). Then, the adsorbent to which the cells have been adsorbed is air-dried (step e), and the adsorbent to which the cells have been finally obtained is sealed in a pack after sealing (step f).

The obtained basidiomycete preparation is suspended in a liquid or water at the time of use so that an appropriate cell concentration is obtained. Here, the concentration of the cells when suspended is preferably 0.01 to 5% by weight, particularly preferably 0.01 to 1% by weight. Examples of a method of applying the obtained basidiomycete suspension include a method of directly inoculating a plant and a method of inoculating a rhizosphere soil of a target plant.

[0014] The method of direct inoculation into a plant includes a rubbing method, a spraying method and the like. The rubbing method is
This is a method in which a suspension of a basidiomycete preparation is rubbed against a plant one by one using a gauze or the like. On the other hand, the spraying method
Air compressor (e.g., AIRONE EXONEER100) and spray gun (e.g., Kita Shinsei Seisakusho's Rich 8T.
506W) to inoculate plants in a short time, and the time required for inoculation can be greatly reduced. Moreover, as a method of inoculating the rhizosphere soil, it can be inoculated by a method such as an injection method. The injection method is a method of injecting a basidiomycete preparation directly into soil.

[0015]

EXAMPLES The present invention will now be described specifically with reference to examples, but the scope of the present invention is not limited to these examples. [Example 1] Screening for low-pathogenic purple scab on low-pathogenic purple scab in a stock culture of purple scabs preserved at a fruit tree test site in Fukushima Prefecture by a pathogenicity test using carrots Was screened from. Helicobasidium monpa V-18 having pathogenicity was used as a control in the screening. That is, the bacteria precultured on a potato decoction agar medium were inoculated into autoclaved mulberry cuts having a length of about 1 cm, and cultured at 25 ° C for about 2 months to obtain an inoculum. The carrots cultivated for 2 months on the horticultural culture soil were taken out and connected to a mulberry branch cultured with the test strain by a toothpick cut in half. Next, the inoculated carrots were transplanted into a plastic container containing Kanuma soil, and then placed in a greenhouse.
After cultivation for a month, the pathogenicity was evaluated in six levels from 0 to 5 in Table 1.

[0016]

[Table 1]

In an inoculation test using carrot, isolate V-70 was isolated.
Had a pathogenicity of 2, which was much lower than the standard strain V-18 of 4.75, confirming that the isolate V-70 had low pathogenicity. The thus obtained low pathogenic purple wilt fungus,
It was named as low pathogenic purple wilt disease isolate V-70. Examination of its mycological properties revealed the following.

(A) Cultural and morphological properties Potato decoction agar medium Amorphous to round, fluffy, purplish brown Oatmeal agar medium Amorphous to round, felt, purpleish (b ) Physiological properties Optimal growth temperature 25 ° C (c) Other properties Pathogenicity Remarkably lower than standard purple wilt disease strain

[0019]

Industrial Applicability According to the present invention, there are provided a low-pathogenic purple wilt fungus and a purple wilt control agent containing the same.

[Brief description of the drawings]

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a view showing a method for evaluating the pathogenicity of a purple wilt fungus isolate.

FIG. 2 is a view showing a process for producing a basidiomycete preparation.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yukari Uetake 1-21-2-7 Kannondai, Tsukuba City, Ibaraki Prefecture Canon 21-213 (72) Inventor Koichi Suzaki RC3-15, Akahira 4 Shimogurikawa, Morioka City, Iwate Prefecture 72) Inventor Koji Yoshida 2-11-9 Kitamatsuen, Morioka City, Iwate Prefecture (56) References "Preprints of the Abstracts of the 1999 Annual Meeting of the Japanese Society of Plant Pathology" (March 15, 1999) Japanese Plant Pathology Society p. 34 Phytopathology, 89 (6 Supplement), S58 (June 1999) Agricultural Research News, (40), 4-5 (1998) (58) Fields investigated (Int. Cl. ⁷ , DB name) C12N 1/14- 1/19 A01N 63/00-63/04 BIOSIS (DIALOG) JICST file (JOIS) WPI (DIALOG)

Claims (1)

(57) [Claims] (1) Helicobasidium monpa (Helicoba)
sidium mompa) FERM P-17536 strain.