Screening and Evaluation of Streptomyces Species as a Potential Biocontrol Agent against a Wood Decay Fungus, Gloeophyllum trabeum

Figures & data

Table 1. Wood decay fungi used for testing the antifungal activity of Streptomyces spp.

Culture collection No.	Species
TPML 13119 (KACC 46180, CBS 236.91)	Donkioporia expansa
TPML 12104 (KACC 46194, CBS 164.27)	Gloeophyllum trabeum
TPML 13123 (KACC 46294, CBS 103.20)	Schizophyllum commune
TPML 11015	Trametes versicolor

Table 2. Identity of five Streptomyces spp. isolated in this study.

Species	Culture collection No.	Accession No.
Streptomyces sp. 1	TPML 13102	MG923820
Streptomyces sp. 2	TPML 13104	MG923821
Streptomyces sp. 3	TPML 13105	MG923822
Streptomyces sp. 4	TPML 13106	MG923823
Streptomyces sp. 5	TPML 13108	MG923824
Streptomyces sp. 6	TPML 13094	MG972195

Table 3. Antifungal activity of Streptomyces spp. against four WDF.

	Tested WDF
Culture collection No.	G. trabeum	T. versicolor	D. expansa	S. commune
TPML 13102	+++	++	++	++
TPML 13104	++	+	++	++
TPML 13105	++	++	++	++
TPML 13106	+++	++	++	++
TPML 13108	+++	++	++	+
TPML 13094	+++	++	++	++

45 mm < + ≤ 65 mm; 25 mm < ++ ≤ 45 mm; +++ ≤ 25 mm.

Table 4. Suppression rate (%) of the growth of WDF.

	Antagonistic microorganism
	Streptomyces spp.						Fungi (Control)
Wood decay fungi	Streptomyces sp. 1 (TPML13102)		Streptomyces sp. 2 (TPML13106)		Streptomyces sp. 3 (TPML13094)		Trichoderma atroviride (TPML13118)		T. viride (TPML13117)		T. harzianum (TPML13115)		T. virens (TPML13116)		Gliocladium roseum (TPML13114)
	H	U	H	U	H	U	H	U	H	U	H	U	H	U	H	U
Gloeophyllum trabeum (TPML 12104)	72.8	77.7	51.4	64.1	61.1	65.9	57.4	68.0	2.1	4.3	13.1	6.4	1.4	4.8	13.6	18.4
Trametes versicolor (TPML 11015)	53.5	76.4	36.5	54.0	42.6	54.2	42.0	59.5	46.0	43.1	13.6	16.9	44.7	46.4	3.1	9.5
Donkioporia expansa (TPML 13119)	21.9	27.6	13.8	24.9	19.8	28.6	70.3	76.3	12.9	29.3	12.6	9.5	10.4	17.1	17.3	23.9
Schizophyllum commune (TPML 13123)	61.3	68.0	38.0	42.7	51.5	58.4	9.9	15.9	27.1	38.8	6.9	3.0	21.7	0.2	14.4	14.8

Figure 1. Comparison of the weight loss (%) of Pinus densiflora wood blocks treated with the selected Streptomyces spp. at 120 days after inoculation with Gloeophyllum trabeum. Means with the same letter on the bar are not significantly different, as analyzed with Tukey’s honestly significance difference test (p = .017 at 95% confidence interval).

Figure 2. Comparison of the compression strength (perpendicular or parallel to the grain) of Pinus densiflora wood blocks subjected to treatment with selected Streptomyces spp. for 120 days after inoculation with Gloeophyllum trabeum. Means with the same letter on the bar are not significantly different based on Tukey’s honestly significance difference test (p = 1.708e⁻⁰⁵ and 2.536e⁻⁰⁵ at 95% confidence interval for compression strength perpendicular and parallel to the grain, respectively).

Figure 3. Comparison of the bending strength of Pinus densiflora wood blocks treated with the selected Streptomyces spp. for 120 days after inoculation with Gloeophyllum trabeum. Means with the same letter on the bar are not significantly different, based on Tukey’s honestly significance difference test (p = .017 at 95% confidence interval).

Figure 4. Analysis of changes in the chemical components, including lignin and holocellulose, at 120 days after inoculation with Gloeophyllum trabeum on the wood block of Pinus densiflora treated with the selected Streptomyces spp. (p < 2e⁻¹⁶ at 95% confidence interval).

Figure 5. Scanning electron micrographs (×150, ×1000, and ×5000) of cross-sections of Pinus densiflora specimens at 120 days after its inoculation with Gloeophyllum trabeum. Blocks treated with Streptomyces sp. 1 (A–C) and the non-treated controls (D–F). (A, D) bar 200 μm; (B, E) bar 20 μm; (C, F) bar 10 μm.