AU2020343993B2

AU2020343993B2 - Use of Serratia marcescens in preparing termite antifeedant

Info

Publication number: AU2020343993B2
Application number: AU2020343993A
Authority: AU
Inventors: Yong Chen; Zhiqiang Li; Bingrong Liu; Wenhui Zeng; Shijun Zhang
Original assignee: Institute of Zoology of Guangdong Academy of Sciences
Current assignee: Institute of Zoology of Guangdong Academy of Sciences
Priority date: 2020-05-12
Filing date: 2020-08-13
Publication date: 2022-02-24
Anticipated expiration: 2040-08-13
Also published as: AU2020343993A1; WO2021057308A1; CN111357770A; CN111357770B

Abstract

Disclosed is the use of Serratia marcescens in preparing a termite antifeedant. The termite antifeedant is prepared in the form of a liquid culture of a Serratia marcescens strain. Serratia marcescens is featured by the simple culturing condition, short growth cycle, rapid growth rate, and 5 easy propagation, while being not a chemical agent, and therefore it can be used as a promising termite antifeedant.

Description

USE OF SERRATIA MARCESCENS IN PREPARING TERMITE ANTIFEEDANT TECHNICAL FIELD

The present invention relates to the field of termite control, and particularly relates to the use

of Serratiamarcescens in preparing a termite antifeedant.

BACKGROUND

Termites are globally distributed insects that cause severe damages especially in tropical and

subtropical zones. In China, termites have been found in 23 provincial regions, affecting nearly

40% of the total area of China. They spread and destroy rapidly and thus can cause huge damages

in a short period of time, causing economic losses of about 2-2.5 billion Yuan every year (LI

Xiaoying and WANG Yiyan, 2003). At present, termite control mainly relies on chemical methods,

which cause severe damages to environment but do not work well especially in urban control or

aged wood protection; these methods may also cause damages to human body or aged wood.

Serratia marcescens, a bacterium of the genus Serratia widely occurs in nature, presents

antiviral, immunoenhancing, and insecticidal functions, and inhibitory activities against fungi,

bacteria, malaria, and mould. Currently, it has been found to exhibit pathogenicity to many insect

species, and can infect several insect species in the order Lepidoptera, Coleoptera, and

Homoptera.

SUMMARY

The present invention relates to a novel use of a Serratia marcescens strain, and specifically,

the use of Serratia marcescens in preparing a termite antifeedant. The Serratiamarcescens strain

has been deposited under the accession number GDMCC No. 60999.

The termite antifeedant is prepared from Serratia marcescens in the form of a liquid culture

of the Serratia marcescens strain. The liquid culture of the Serratiamarcescens strain is used as a

termite antifeedant by spraying or soaking a material that needs protection.

The liquid culture of the Serratia marcescens strain may be obtained by inoculating the

Serratia marcescens strain to a liquid LB medium, and incubating on a shaker at 200 r/min and

25±1°C for 48 hours.

The present invention also relates to a termite antifeedant, comprising a liquid culture of the

Serratia marcescens strain having the accession number GDMCC No. 60999 as an active

ingredient.

Further, the present invention relates to a method of deterring the feeding of termites,

comprising spraying or soaking a material that needs protection with a liquid culture of the

Serratiamarcescens strain having the accession number GDMCC No. 60999.

Moreover, the present invention relates to a Serratia marcescens strain having the accession

number GDMCC No. 60999.

The use of the liquid culture of the Serratia marcescens strain as an antifeedant was verified

by wetting filter papers with a liquid culture of the Serratia marcescens strain and inspecting the

feeding of termites on the filter papers. Consequently, the filter papers were subjected to extreme

treatment (high-temperature drying), and its efficacy was proved again. Since Serratia

marcescens is featured by the simple culturing condition, short growth cycle, rapid growth rate,

and easy propagation, while being not a chemical agent, it can be used as a promising termite

antifeedant.

The Serratia marcescens strain CfI2019 involved in the present invention has been deposited

with Guangdong Microbial Culture Collection Center (GDMCC, Building No. 59, No. 100

Xianliezhong Road, Guangzhou) under the accession number GDMCC No. 60999 on 17 April

2020.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the feeding (day 5) of termites in Embodiment 1. The 10 petri dishes in the

upper part of the figure contained filter papers treated with a liquid culture of the Serratia

marcescens strain, while the 10 petri dishes (control group) in the lower part contained filter papers treated with an LB medium without Serratiamarcescens.

FIG. 2 shows the consumption (day 5) of the filter papers by the termites in Embodiment 1.

Symbol "*" represents that there is significant difference between different treatments. Error bars

are added to indicate the range of standard deviations.

FIG. 3 shows the feeding (day 5) of termites in Embodiment 2 (extreme treatment). The 10

filter papers in the upper part of the figure were treated with a liquid culture of the Serratia

marcescens strain, while the 10 filter papers (control group) in the lower part were treated with an

LB medium without Serratia marcescens.

FIG. 4 shows the consumption (day 5) of the filter papers by the termites in Embodiment 2

(extreme treatment). Symbol "*" represents that there is significant difference between different

treatments. Error bars are added to indicate the range of standard deviations.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The embodiments described below are for further illustrating the present invention rather

than limiting the present invention.

Embodiment 1

Serratia marcescens, a species of family Enterobacteriaceae and genus Serratia, is a

Gram-negative and short rod-shaped bacterium. Morphologically, Serratia marcescens has a

smaller size as compared with other enteric bacteria, lacks a capsule, and sometimes has a

filamentous shape. It is featured by its ability to produce a secondary metabolite called

prodigiosin, which is largely affected by temperature that it produces prodigiosin only at a

temperature around 25°C while stops producing prodigiosin once the temperature reaches 37°C.

The Serratia marcescens strain involved in the present invention is isolated from termites died in

the laboratory, and has been deposited with Guangdong Microbial Culture Collection Center

(GDMCC, Building No. 59, No. 100 Xianliezhong Road, Guangzhou) under the accession

number GDMCC No. 60999 on 17 April 2020.

The Serratia marcescens strain was inoculated to a liquid LB medium, and incubated on a shaker at 200 r/min and 25±1°C for 48 hours so as to obtain a liquid culture for later use.

Circular filter papers with an identical size were dried and weighed, and thereby their initial

weights were recorded. The filter papers were then placed in circular petri dishes and sprayed

with the liquid culture of the Serratia marcescens strain; then a termite colony of a particular

population size (19 workers and 1 soldier) were introduced to each petri dish. Concurrently, filter

papers sprayed with an LB medium without Serratia marcescens were also investigated as a

control group, and also termite colonies of the same population size were introduced. Each group

comprised 10 replicates. After a 5-day period, the filter papers were collected and, after termite

droppings and other feeding debris were removed, dried in an oven at 80°C for 72 hours. The

dried filter papers were weighed and thereby their final weights were recorded. The consumption

of a filter paper by the termites was calculated by subtracting its final weight from its initial

weight.

FIG. 1 shows the feeding of termites after the 5-day period. As can be seen from the figure,

the filter papers sprayed with the LB medium without Serratia marcescens in the control group

were eaten, while the filter papers treated with the liquid culture were barely eaten.

A significant increase in mortality was not observed in the treated group, demonstrating that

termite mortality was an inconsiderable factor for the decrease in feeding. Statistical analysis

illustrated that the liquid culture treatment group exhibited a significant decrease in consumption

as compared with the control group the filter papers were sprayed with the LB medium without

Serratia marcescens. The treatment with the liquid culture of the Serratiamarcescens strain was

determined to give a feeding deterrent activity (FIG. 2) as described below:

The average consumption of filter papers in the liquid culture treated group (average initial

weight - average final weight = average consumption; 0.0948 g - 0.0939 g = 0.0009 g) was

significantly lower than that in the LB treated group (0.0932 g - 0.0801 g = 0.0131 g) (t = -8.03, p

<0.001).

Embodiment 2

The dried filter papers (i.e. after subjected to the high-temperature extreme treatment) in

Embodiment 1 were again placed in the petri dishes. The filter papers of the two treatments (i.e.

liquid culture treatment with Serratia marcescens, and LB medium treatment without Serratia

marcescens) were both sprayed with sterilized water; then again a termite colony of the particular

population size (19 workers and 1 soldier) were introduced to each petri dish. After a 5-day period,

the filter papers were collected and, after termite droppings and other feeding debris were

removed, dried in an oven at 80°C for 72 hours. The dried filter papers were weighed and thereby

their final weights were recorded. The final weights recorded in Embodiment 1 were used as the

initial weights in Embodiment 2. The consumption of a filter paper by the termites after the

extreme treatment was calculated by subtracting its final weight from its initial weight.

FIG. 3 shows the feeding of termites after the 5-day period. As can be seen from the figure,

after the extreme treatment, the filter papers sprayed with the LB medium without Serratia

marcescens in the control group were eaten more, while the filter papers treated with the liquid

culture were eaten slightly.

Statistical analysis illustrated that, after the extreme treatment, the consumption of filter

papers treated with the liquid culture increased but was still at a very low level, significantly

lower than the control group treated with LB medium. The treatment with the liquid culture of the

Serratia marcescens strain was again determined to give a feeding deterrent activity (FIG. 4) as

described below:

After the extreme treatment, the average consumption in the liquid culture treated group

(average initial weight - average final weight = average consumption; 0.0939 g - 0.0904 g =

0.0035 g) was significantly lower than that in the LB treated group (0.0801 g - 0.0684 g = 0.0117

g) (t = -7.91, p < 0.001).

The results of Embodiments 1 and 2 demonstrated that, spraying of the liquid culture of

Serratia marcescens could significantly reduce the consumption of filter papers by the termites,

i.e. Serratia marcescens exhibited a particular feeding deterrent activity. Furthermore, after the

extreme treatment (high-temperature treatment at 80°C for 3 days), the filter papers treated with

the liquid culture still exhibited a strong feeding deterrent activity. Thus, the liquid culture of

Serratia marcescens can be used as a termite antifeedant and applied in the protection of materials such as wood and buildings.

The above embodiments are only the preferred embodiments of the present invention. It

should be noted that the above preferred embodiments should not be regarded as limiting the

present invention, and the scope of the present invention should be defined by the claims.

It will be understood that the terms "comprise" and "include" and any of their derivatives (e.g.

comprises, comprising, includes, including) as used in this specification, and the claims that

follow, is to be taken to be inclusive of features to which the term refers, and is not meant to

exclude the presence of any additional features unless otherwise stated or implied.

Claims

The claims defining the invention are as follows:

1. Use of a Serratia marcescens strain Cf2019 having the accession number GDMCC No.

60999 in preparing a termite antifeedant, wherein the termite antifeedant is prepared in the form of

a liquid culture of the Serratia marcescens strain.

2. The use according to claim 1, comprising spraying or soaking a material that needs

protection with the liquid culture of the Serratiamarcescens strain.

3. The use according to claim 1, wherein the liquid culture of the Serratia marcescens strain is

obtained by incubating the Serratia marcescens strain in a liquid LB medium.

4. The use according to claim 3, wherein the liquid culture of the Serratia marcescens strain is

obtained by inoculating the Serratia marcescens strain to the liquid LB medium, and incubating on

a shaker at 200 r/min and 25±1°C for 48 hours.

5. A termite antifeedant, comprising a liquid culture of a Serratia marcescens strain having the

accession number GDMCC No. 60999 as an active ingredient.

6. A method of deterring the feeding of termites, comprising spraying or soaking a material

that needs protection with a liquid culture of a Serratia marcescens strain having the accession

number GDMCC No. 60999.

7. An isolated Serratia marcescens strain having the accession number GDMCC No. 60999.