Assessments of novel transgenic germplasm and treatment with the phytohormone cytokinin for reducing feeding damage by flea beetles, Phyllotreta spp. (Coleoptera: Chrysomelidae) in canola

Flea beetles [Phyllotreta cruciferae (Goeze) and Phyllotreta striolata (Fabricius)] (Coleoptera: Chrysomelidae) pose significant threats to early canola seedling establishment. The resistance potential of transgenic Brassica napus expressing cDNA encoding pea PR10.1 and 10.4 (ABR17) in Westar and DH19 backgrounds, respectively, was investigated. In addition, the effects of treatments with different concentrations of the cytokinin 6-benzylaminopurine (BAP) and with Helix® (thiamethoxam insecticide) on flea beetle tolerance were investigated. Our results indicate that transgenic lines expressing PR10.1 and PR10.4 suffered the least damage from P. cruciferae when compared with Helix ®-treated doubled haploid or Westar genotypes, while cytokinin treatments conferred some tolerance. P. striolata experiments demonstrated that insecticide treatments were most effective for reducing damage. Helix® treatments displayed the most significant beetle mortality while neither PR10.1, PR10.4 nor cytokinin treatments demonstrated insecticidal activity. Proteomic analysis revealed significant increases in abundance of some proteins including protease inhibitors in ABR17 seedlings damaged by herbivory.