Data on the ultrastructural characteristics of Paenibacillus polymyxa isolates and biocontrol efficacy of P. polymyxa ShX301.

We present the data corresponding to the ultrastructural characteristics of Paenibacillus polymyxa isolates and control efficacy of P. polymyxa ShX301 for controlling Verticillium wilt of cotton, isolated in experimental fields at the Sanyuan Agricultural Experiment Station of North-West Agriculture and Forestry University, Sanyuan county, Shaanxi province, China. Ultrastructural characteristics of P. polymyxa isolates made using technique of transmission electron microscopy. A strain ShX301 has a broad-spectrum antifungal activity against V. dahliae and other plant pathogens and has been used for in vitro experiments for controlling this disease in greenhouse, "Biocontrol potential of Paenibacillus polymyxa against Verticillium dahliae infecting cotton plants" [1].

Specifications table

Value of the data

Our data provide the evidence that hints the three-layered spore coat is possibly a common feature in genus Peanibacillus.

Biocontrol assay showed that P. polymyxa strain ShX301 has great potential using as biocontrol bacterium for controlling Verticillium wilt of cotton.

The data can be used for general analysis of bacterial identification and screening of biocontrol strains.

Data

Sporulation process of Paenibacillus polymyxa strain ShX301 was described [1], which was similar to that described in P. motobuensis by Iida et al. [2]. While other four strains (Hb1, Hb6, ShX302 and ShX303) of P. polymyxa also shared the same characteristics with strain ShX301. The mature spores in the sporangia all had the three-layered spore coats in the four strains (Fig. 1).

Fig. 1

Transmission electron micrographs of endospores of Paenibacillus polymyxa grown on specific spore-forming medium at 30 °C for 48 h. A. Strain Hb1. B. Strain Hb6. C. Strain ShX302. D. Strain ShX303. ISC: inner spore coat. OSC: outer spore coat. MSC: middle spore coat. Bar = 0.5 µm.

Inoculation tests showed that inoculation by strain ShX301 reduced disease incidence and severity (1). The raw information related to disease incidence and severity contained in the Table 1.

Table 1

Inhibitory efficacy of P. polymyxa ShX301 against Verticillium wilt of cottona.

Disease grade		0	1	2	3	4	Disease severity (%)
Treatment1 (V. dahliae+P. polymyxaShX301)	R1	48	2	4	6	2	15.30	13.50 ± 1.58
	R2	50	1	4	5	2	12.90
	R3	48	3	7	3	1	12.31
Treatment2 (V. dahliae)	R1	3	20	14	12	13	57.63	53.83 ± 1.67
	R2	6	21	12	13	11	50.29
	R3	5	21	10	14	13	53.57
Ck1 (P. polymyxaShX301)	R1	61	0	0	0	0	0.0	0.0
	R2	61	0	0	0	0	0.0
	R3	63	0	0	0	0	0.0
Ck2 (sterile water)	R1	62	0	0	0	0	0.0	0.0
	R2	63	0	0	0	0	0.0
	R3	61	0	0	0	0	0.0

ΔDisease severity was assessed for each plant on a 0 to 4 rating scale according to the percentage of foliage affected by acropetal chlorosis, necrosis, wilt, and/or defoliation (0 = healthy plant, 1 = 1 to 33%, 2 = 34 to 66%, 3 = 67 to 99%, 4 = dead plant)as described by Bejaranoalcazar et al. [3].

The disease assessment was carried out 45 days after planting for each plant on a 0 to 4 rating scale (0 = healthy plant, 1 = 1–33%, 2 = 34–66%, 3 = 67–99%, 4 = dead plant). Disease severity (%) = Σ (disease ratings × number of plants)/(maximum rating value × Total number of plants) × 100. R: repetition.

Experimental design, materials and methods

For endospore observation, bacterial strains were grown on specific spore-forming medium (10 g beef extract, 2 g yeast extract, 0.04 g manganese II sulphate monohydrate, 25 g agar, pH 7.2) for two days at 25 °C [4]. Ultrastructural characteristics were observed using a JEM-1010 transmission electron microscope (JEOL USA Inc., Peabody, MA, USA).

The seeds of a susceptible cotton (Gossypium hirsutum cv. Ejing-1) were used. The disease assessment was carried out 45 days after planting. Disease severity was assessed for each plant on a 0 to 4 rating scale [3]. Please see the publication "Biocontrol potential of Paenibacillus polymyxa against Verticillium dahliae infecting cotton plants." (Zhang et al. [1]) for the details of Experimental design, materials and methods.

Subject area	Biology
More specific subject area	Microbiology, Microscopy
Type of data	Transmission electron microscopy (TEM) images, Tables
How data was acquired	TEM following an optimized cell preparation protocol
	Statistical analysis explained in the text of this article
Data format	Analyzed
Experimental factors	Bacterial cells were grown in solid media for TEM observation, inoculation and experiment condition (explained in the text of this article)
Experimental features	Ultrastructural characteristics were made using technique of transmission electron microscopy
Data source location	Paenibacillus polymyxa isolates were isolated from the experimental fields at the Sanyuan Agricultural Experiment Station of North-West Agriculture and Forestry University, Sanyuan county, Shaanxi province, China.
Data accessibility	Data incorporated within this article and the sequences of Paenibacillus polymyxa isolates has been deposited in GenBank under the accession numberKX458008,KX458009andKX458010.