Effect of the protein elicitor AMEP412 from Bacillus subtilis artificially fed to adults of the whitefly, Bemisia tabaci (Genn.) (Hemiptera: Aleyrodidae)

Quan Liu,Yongrui Shen,Kuide Yin,Binbin Zhang

doi:10.1186/s41938-019-0202-0

Quan Liu, Yongrui Shen + Show 2 more

Open Access

https://doi.org/10.1186/s41938-019-0202-0

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Abstract

In a previous study, we identified a protein elicitor AMEP412 from Bacillus subtilis, which could trigger plant defense response and induce systemic acquired resistance. In the present study, the toxicity of AMEP412 against the whitefly Bemisia tabaci (Genn.) (Hemiptera: Aleyrodidae) was reported. The purified protein samples at different concentrations (1, 5, 10, 20, 40, and 80 μg/ml) caused 17–96% mortality 2 days post-artificial adult feeding, where the median lethal concentration (LC50) was calculated by 15.57 μg/ml. The stability test showed that AMEP412 had a good stability against thermo and natural degradation. The fluorescence localization assay revealed that AMEP412 could be taken into the whitefly adult body and localized in the gut. Based on the feature of this protein, AMEP412 was probably digested by gut proteases and led to the release of hydrophobic fragments in the insect gut. It was deduced that these hydrophobic peptides could insert themselves into the cell membrane and form lytic pores, leading to content leakage and cell lysis, followed by insect death. This study sheds a light on the toxic effect of AMEP412, which not only enriched the function of the protein elicitor but also provided a new choice for the biocontrol of whiteflies.

Highlights

The whitefly Bemisia tabaci (Genn.) (Hemiptera: Aleyrodidae) is an important insect pest to several crops, including vegetables, cotton, and ornamentals (Byrne and Bellows 1991)
The Lethal concentration to kill 50% population (LC50) value was calculated as 15.57 μg/ml (fiducial limits = 10.86–21.00; slope = 2.10; 95% confidence interval (CI) for slope 1.55–2.66; χ2 for heterogeneity 0.83 calculated; χ2 significance value 0.84) (Table 1)
In a previous study (Shen et al 2019), AMEP412 was first reported as a protein elicitor with the function of eliciting plant’s defense response and promoting plant’s disease resistance

Summary

Introduction

The whitefly Bemisia tabaci (Genn.) (Hemiptera: Aleyrodidae) is an important insect pest to several crops, including vegetables, cotton, and ornamentals (Byrne and Bellows 1991). It damages crops by feeding on phloem and transmitting plant viruses, leading to tremendous losses in agricultural production and national economies (Reitz 2007; Navas-Castillo et al 2011). The main strategy of controlling the whitefly was mainly based on chemical insecticides. Exploring insecticides with novel mode of action should be a new focus. Proteins with insecticidal activity acted in different modes, which lead to

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