Isolation, Identification, Biocontrol Activity, and Plant Growth Promoting Capability of a Superior Streptomyces tricolor Strain HM10

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Characteristics of eleven Actinomycetes strains_

Symbol of isolate	Pigmentation	Opacity of colony	Colony consistency	Growth under the surface of liquid media
Streptomyces griseorubens strain HM1 (Actino1)	Brown	Opaque	Rough	Sediment of balls
Streptomyces sp. strain HM2 (Actino2)	White	Opaque	Rough	Sediment of balls
Streptomyces thinghirensis strain HM3 (Actino4)	Yellow*	Opaque	Rough	Sediment of balls
Streptomyces sp. strain HM4 (Actino5)	Yellow	Opaque	Rough	Sediment of balls
Actino7	Red	Opaque	Rough	Sediment of balls
Streptomyces sp. strain HM6 (Actino8)	Cream	Opaque	Rough	Sediment of balls
Streptomyces panayensis strain HM7 (Actino9)	Cream	Opaque	Rough	Sediment of balls
Streptomyces sp. strain HM8 (Actino MS9)	Dark brown	Opaque	Rough	Sediment of balls
Actino10	Cream light pink	Opaque	Rough	Sediment of balls
Actino11	Cream	Opaque	Rough	Sediment of balls
Streptomyces tricolor strain HM10 (Actino12)	Yellow**	Opaque	Rough	Sediment of balls

Antagonism of eight identified Streptomyces strains against ten different plant pathogenic fungi_

Isolates	Tested Fungi*
	F. mon	F. so	F. ox	F. gra	Collet	Bot	Alt	Rhiz	Myro	Thiel	Total
Streptomyces griseorubens strain HM1	–	–	+++3 mm	–	–	–	–	–	–	–	1
Streptomyces sp. strain HM2	–	–	–	–	–	–	–	–	–	–	0
Streptomyces thinghirensis strain HM3	+++5 mm	+++9 mm	+++8 mm	+++8 mm	+++8 mm	+++15 mm	+++12 mm	+++11 mm	+++3 mm	+++7.5 mm	10
Streptomyces sp. strain HM4	–	–	–	–	+++7 mm	+++5 mm	+++4 mm	+++2 mm	–	–	4
Actino7	+	+++3 mm	+	+++5 mm	–	+++9 mm	+++1 mm	+++2 mm	+++10 mm	+++3 mm	5
Streptomyces sp. strain HM6	–	–	–	–	–	–	–	–	–	–	0
Streptomyces panayensis strain HM7	–	–	–	–	–	–	–	–	–	–	0
Streptomyces sp. strain HM8	–	–	–	–	–	–	–	–	–	–	0
Actino10	–	–	–	+++11 mm	+++1 mm	–	+++3 mm	–	–	–	3
Actino11	–	–	–	–	–	–	–	–	–	–	0
Streptomyces tricolor strain HM10	+++11 mm	+++12 mm	+++13 mm	+++11 mm	+++18 mm	+++16 mm	+++8 mm	+++1 mm	+++13 mm	+++ 16 m	10
Total	3	3	4	3	4	3	5	3	2	3

Effects of Streptomyces tricolor HM10 and Streptomyces thinghirensis strain HM3 crude extracts on the viability of A549 cancer cells_ Treated versus untreated cells (p > 0_05)_

Streptomyces thinghirensis HM3 (μg/ml)	% Cells Viability (Mean + SD)	Streptomyces tricolor strain HM10 (μg/ml)	Cells Viability (%) (Mean ± SD)
Untreated cells	98.3 ± 8.2	Untreated cells	99.1 ± 6.1
20	98.2 ± 9.2	20	99.2 ± 5.5
40	97.4 ± 6.8	40	98.3 ± 6.6
60	98.5 ± 7.3	60	97.1 ± 4.6
80	97.3 ± 9.6	80	98.2 ± 7.3
100	96.2 ± 9.1	100	98.3 ± 8.8
120	98.4 ± 7.2	120	97.7 ± 9.5
140	98.8 ± 9.5	140	99.1 ± 6.4
160	96.2 ± 9.1	160	98.2 ± 7.2
180	98.2 ± 8.2	180	97.1 ± 7.3
200	97.1 ± 8.5	200	98.3 ± 9.5

Identified Streptomyces strains via 16S rRNA amplicon sequencing and their similarity with identified strains at the NCBI website_

No.	The isolated strain	Streptomyces similar strain	Similarity (%)
1	Streptomyces griseorubens strain HM1 (Actino1)	Streptomyces griseorubens strain SELJFHG3	99.46
2	Streptomyces sp. strain HM2 (Actino2)	Streptomyces sp. SYP-A7193	99.85
3	Streptomyces thinghirensis strain HM3 (Actino4)	Streptomyces thinghirensis strain TG26	99.62
4	Streptomyces sp. strain HM4 (Actino5)	Streptomyces sp. E4N275g	99.46
5	Streptomyces sp. strain HM6 (Actino8)	Streptomyces sp. SYP-A7193	99.23
6	Streptomyces panayensis strain HM7 (Actino9)	Streptomyces panayensis	99.54
7	Streptomyces sp. strain HM8 (ActinoMS9)	Streptomyces sp. strain 16K303	99.46
8	Streptomyces tricolor strain HM10 (Actino12)	Streptomyces tricolor strain AS 4.1867	99.77

The production of siderophores, extracellular indole-3-acetic acid (IAA) and phosphor fixing of eleven isolated Streptomyces strains_

Isolate	Iron1				Phosphor2	IAA3 µg/ml
	Reaction	Width	D/D colony	h/c
Streptomyces griseorubens strain HM1	++	2 mm	9.5/5.5	1.98	+	77.19
Streptomyces sp. strain HM2	++	1.5 mm	10.1/7.5	2.15	+	89.36
Streptomyces thinghirensis strain HM3	+	1 mm	11/8	1.67	Trace	86.66
Streptomyces sp. strain HM4	++	2.5 mm	11/5.5	3.36	–	72.26
Actino7	+++	5 mm	16.5/8	4.25	–	112.96
Streptomyces sp. strain HM6	++	2 mm	11.5/7.5	2.35	–	43.65
Streptomyces panayensis strain HM7	+++	5 mm	14/4	12.25	+	99.3
Streptomyces sp. strain HM8	+++	11 mm	24/3	64	Trace	75.6
Actino10	+++	10 mm	25.5/4.5	32.1	+	172.13
Actino11	+++	9 mm	20/3.5	32.65	–	270.33
Streptomyces tricolor strain HM10	+++	11.5 mm	28.5/6	22.56	+	273.02

The antagonism effect of eight identified Streptomyces strains against three bacterial strains_

Isolates	Pseudomonas putida	Escherichia coli	Bacillus subtilis	Total
Streptomyces griseorubens strain HM1	+ 3 mm	–	–	1
Streptomyces sp. strain HM2	–	–	–	1
Streptomyces thinghirensis strain HM3	–	+ 12 mm	Trace 3 mm	2
Streptomyces sp. strain HM4	–	–	–	0
Streptomyces sp. strain HM6	–	–	–	0
Streptomyces panayensis strain HM7	–	–	–	0
Streptomyces sp. strain HM8	–	–	–	0
Streptomyces tricolor strain HM10	–	–	–	0