Location: Molecular Plant Pathology Laboratory
Title: Growth inhibition of phytopathogenic spiroplasmas by membrane-interactive antimicrobial peptides Novispirin T7 and Caerin 1.1Author
|
Submitted to: Annals of Applied Biology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 5/11/2021 Publication Date: 7/2/2021 Citation: Wei, W., Davis, R., Mowery, J.D., Zhao, Y. 2021. Growth inhibition of phytopathogenic spiroplasmas by membrane-interactive antimicrobial peptides Novispirin T7 and Caerin 1.1. Annals of Applied Biology. https://doi.org/10.1111/aab.12715. DOI: https://doi.org/10.1111/aab.12715 Interpretive Summary: Spiroplasmas are helical, motile bacteria without a cell wall. These bacteria have a broad range of hosts including plants, arthropods, and vertebrates. Spiroplasma kunkelii and Spiroplasma citri are plant pathogenic and are responsible for corn stunt disease and citrus stubborn disease, respectively. Both diseases have high impacts on agriculture and economy. Crops exhibiting natural resistance to spiroplasmal diseases are currently lacking. In the present study, as part of an effort to engineer artificial plant resistance against spiroplasmal diseases, ARS scientists searched and tested short antimicrobial peptides (AMPs) for their abilities to fight spiroplasmas. The study identified two AMPs that were effective in inhibiting the growth of S. kunkelii and S. citri under laboratory conditions. The efficacies of the AMPs were comparable to that of tetracycline, a potent antibiotic. Results from the study also indicated that the AMPs could interact with spiroplasma membrane and deform the cells. This report will be of interest to farmers and extension personnel who are concerned with spiroplasmal disease management. The findings will also be of interest to research scientists and agricultural biotechnologists for genetic engineering of disease resistance. Technical Abstract: Spiroplasma kunkelii and S. citri, both helical-shaped cell wall-less bacteria, are the causative agents of corn stunt disease and citrus stubborn disease, respectively. Plants exhibiting natural resistance to these phytopathogenic spiroplasmas are currently lacking. Engineering artificial plant resistance using antimicrobial peptides (AMPs) has been conceived as a new approach to control the agronomically important spiroplasmal diseases. In preparation for such task, the present study focused on screening of AMPs that have potentials to curb the growth of S. kunkelii and S. citri. Four AMPs, including Novispirin T7, Caerin 1.1, Tricholongin, and Dhvar4, were selected for in vitro growth inhibition tests. A liquid assay method was developed for quick qualitative and quantitative evaluations of the AMPs. Our results demonstrated that Novispirin T7 and Caerin 1.1 were able to inhibit the growth of both phytopathogenic spiroplasmas with the efficacy comparable to that of tetracycline. Cell deformations were observed in spiroplasma cultures treated with these two peptides, indicating interactions of the AMPs with the spiroplasma cell membranes. The minimum inhibitory concentrations (MICs) of the AMPs against S.citri and S. kunkelii were determined. |
