Citrus canker caused by Xanthomonas citri subp. Citri (Xcc), is a serious disease in citrus-producing areas. While different levels of resistance to the disease have been reported, they are not sufficient to provide disease control. Overexpression of antibacterial genes is a potential way to increase plant resistance. Previous studies showed that sarcotoxin IA, an antimicrobial peptide from the flesh fly (Sarcophaga peregrina), can be efficient to control different plant pathogenic bacteria.

Adilson K. Kobayashi from Instituto Agronômico do Paraná – IAPAR in Brazil developed transgenic "Pera" sweet orange (Citrus sinensis) expressing the sarcotoxin IA peptide. Citrus canker resistance evaluation in leaves of transgenic and non-transgenic plants was then performed through inoculations with Xcc.

The Xcc population was significantly lower in leaves of the transgenic plants compared to non-transgenic controls. Incidence of canker lesions was also significantly higher in non-transformed controls than in the transgenic plants after inoculation.

Analysis also showed that accumulation of sarcotoxin IA peptide in sweet orange tissues did not cause any deleterious effects on the growth and development of the transgenic plants.

For more information, read the article in European Journal of Plant Pathology.